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Biosensors for wastewater monitoring: A review
Abstract
Water pollution and habitat degradation are the cause of increasing water scarcity and decline in aquatic biodiversity. While the freshwater availability has been declining through past decades, water demand has continued to increase particularly in areas with arid and semi-arid climate. Monitoring of pollutants in wastewater effluents are critical to identifying water pollution area for treatment. Conventional detection methods are not effective in tracing multiple harmful components in wastewater due to their variability along different times and sources. Currently, the development of biosensing instruments attracted significant attention because of their high sensitivity, selectivity, reliability, simplicity, low-cost and real-time response. This paper provides a general overview on reported biosensors, which have been applied for the recognition of important organic chemicals, heavy metals, and microorganisms in dark waters. The significance and successes of nanotechnology in the field of biomolecular detection are also reviewed. The commercially available biosensors and their main challenges in wastewater monitoring are finally discussed.
... BOD biosensors based on bioreactor technology are mainly developed for online monitoring [35,36]. The principle of operation of these biosensors is based on the analysis of oxygen consumption by microorganisms continuously in contact with the analyzed sample (the process diagram is shown in Figure 7, [37]). ...
... An advantage of bioreactor-type BOD analyzers is the easy replacement of the transducer without disturbing the activity of biomaterial. Besides, a bioreactor BOD biosensor, as compared with a biosensor based on immobilized biomaterial, usually has more stable characteristics [36]. A disadvantage of such devices is that they are stationary and are not suitable for field measurements. ...
... Immobilization determines the lifetime, operational stability, response time, and sensitivity. In this regard, it should be noted that research into the introduction of new immobilization techniques has been constantly under way [36,94]. The most common immobilization methods are adsorption and physical restriction of cells by semipermeable membranes. ...
One of the main indices of the quality of water is the biochemical oxygen demand (BOD). A little over 40 years have passed since the practical application of the first microbial sensor for the determination of BOD, presented by the Japanese professor Isao Karube. This time span has brought new knowledge to and practical developments in the use of a wide range of microbial cells based on BOD biosensors. At present, this field of biotechnology is becoming an independent discipline. The traditional BOD analysis (BOD5) has not changed over many years; it takes no less than 5 days to carry out. Microbial biosensors can be used as an alternative technique for assessing the BOD attract attention because they can reduce hundredfold the time required to measure it. The review examines the experience of the creation and practical application of BOD biosensors accumulated by the international community. Special attention is paid to the use of multiple cell immobilization methods, signal registration techniques, mediators and cell consortia contained in the bioreceptor. We consider the use of nanomaterials in the modification of analytical devices developed for BOD evaluation and discuss the prospects of developing new practically important biosensor models.
... The current water demand exceeds the amount of fresh water on the planet due to rapid urbanization, accelerated growth of populations, industry, etc., which release contaminants that are distributed into aqueous systems [1][2][3]. These activities discharge a large number of harmful contaminants, which become part of the wastewater, where its composition and concentration of microorganisms, inorganic chemical products, and organic contaminants varies according to the origin of the pollutants [4]. The rapid growth of the world population endangers the water balance of ecosystems and generates a significant amount of wastewater [5]. ...
... Likewise, during the pandemic caused by the SARS-CoV-2 coronavirus in 2020, interest was aroused in using biosensors to detect the coronavirus in wastewater, as displayed in the Scopus database, where nine articles were published between 2020-2022 [22][23][24][25][26][27][28][29][30]. Another possible application that has gained interest is the use of biosensors for detecting minimum levels of contaminants in complex matrices such as wastewater [4]. ...
... The monitoring of this type of water possibly began due to the concerns about transferring pathogens and contaminants that put human health at risk [23,28]. However, the use of microbial biosensors in wastewater monitoring continues to attract the attention of the scientific community due to the need for new monitoring alternatives capable of detecting minimum concentrations of pollutants in real-time and thus being able to guarantee public and environmental health [4,40]. Another problem that may have delayed research in this area of biomonitoring was the COVID-19 pandemic [41,42]. ...
Research on the use of microbial biosensors for monitoring wastewater contaminants is a topic that covers few publications compared to their applicability in other fields, such as biomedical research. For this reason, a systematic analysis of the topic was carried out, for which research-type articles were reviewed during the period 2012 to September 2022. For this, different search platforms were used, including PubMed, ScienceDirect, Springer Link, and Scopus, and through the use of search equations a relevant bibliography was located. After that, the research articles were selected based on exclusion criteria. As a result, it was found that, of the 126 articles, only 16 articles were strictly related to the topic, since there was a duplication of articles among the different databases. It was possible to demonstrate the usefulness of microorganisms as components of biosensors to monitor BOD, heavy metals, and inorganic contaminants in wastewater that also had a high sensitivity. Additionally, recombinant DNA techniques were shown to improve the performance of this type of biosensor and can finally be coupled to other emerging technologies, such as microbial fuel cells (MFCs). In conclusion, it was established that microbial biosensors have high acceptability and monitoring characteristics that make them a useful tool to detect low concentrations of pollutants in wastewater that can also provide results in real-time, thus generating forms of ecological safety and social responsibility in companies where wastewater is generated.
... Water quality degradation may be caused by several causes, including the presence of heavy metals, organic contaminants [117]. There are several biosensors used to monitor wastewater such as optical, electrochemical, and thermal [118]. ...
... For the detection of organic compounds in aqueous samples, many whole-microorganism-based biosensors have been created. There was a highly publicized experiment in which a genetically altered cell-based system was combined with luminous as a reporter gene [118]. ...
... To make element detection easier, microalgae immobilisation must be steady throughout the life of the biosensor. Nanomaterials could improve the sensitivity and detection sensitivity of water monitoring biosensors [118]. Biosensors can be used to detect hydrocarbon concentrations in water, however, further studies are required to study the different concentrations and types of hydrocarbons to develop a microalgal biosensor that can be used under various conditions [121]. ...
Biosensors are devices that convert biological responses into electrical signals. Biosensors can be utilised in a variety of applications, including environmental and water quality monitoring, as well as medical applications. Thus, researchers have been working on them and experimenting with new nanofabrication techniques. Nanomaterials like graphene, carbon nanotubes, and nanospheres have provided new and appealing platforms for developing biosensors with improved sensitivity and performance due to their unique features. Microalgae have been used widely in biosensing applications as bioreceptor because they are less likely to be affected by physiochemical changes, in addition to their uses in medical, environmental, industrial, and commercial applications. In this review, we highlight the recent immobilization techniques, support materials like nanomaterials for microalgae immobilization, microfluidics and lab on a chip, the latest genome editing methods, and microalgae applications in medical, environmental, food, and agricultural sectors.
... Various chromatographic and spectroscopic techniques have been used to detect and quantify PhCs. These laboratory techniques require tedious process of sample pretreatment The advantages of using biosensors include high sensitivity, accuracy, short response time, reliability, longer shelf life, and user-friendliness [7,[18][19][20] . Biosensors can detect a very low amount of contaminant even from a composite medium, (wastewater) and are considered reliable for quantifying the total phenolic content in food by checking antioxidant properties of the foodstuff [21,22]. ...
... Berries [17] The advantages of using biosensors include high sensitivity, accuracy, short response time, reliability, longer shelf life, and user-friendliness [7,[18][19][20]. Biosensors can detect a very low amount of contaminant even from a composite medium, (wastewater) and are considered reliable for quantifying the total phenolic content in food by checking antioxidant properties of the foodstuff [21,22]. ...
Phenolic compounds (PhCs) are ubiquitously distributed phytochemicals found in many plants, body fluids, food items, medicines, pesticides, dyes, etc. Many PhCs are priority pollutants that are highly toxic, teratogenic, and carcinogenic. Some of these are present in body fluids and affect metabolism, while others possess numerous bioactive properties such as retaining antioxidant and antimicrobial activity in plants and food products. Therefore, there is an urgency for developing an effective, rapid, sensitive, and reliable tool for the analysis of these PhCs to address their environmental and health concern. In this context, carbonaceous nanomaterials have emerged as a promising material for the fabrication of electrochemical biosensors as they provide remarkable characteristics such as lightweight, high surface: volume, excellent conductivity, extraordinary tensile strength, and biocompatibility. This review outlines the current status of the applications of carbonaceous nanomaterials (CNTs, graphene, etc.) based enzymatic electrochemical biosensors for the detection of PhCs. Efforts have also been made to discuss the mechanism of action of the laccase enzyme for the detection of PhCs. The limitations, advanced emerging carbon-based material, current state of artificial intelligence in PhCs detection, and future scopes have also been summarized.
... Biosensor is one of electrochemical studies that used natural product as based material for sensor [1]- [6]. Biosensor has good selectivity and sensitivity because its specific material that modified on the electrode [4], [7], [8]. ...
... Most of the modified electrodes are platinum, silver and gold [3], [9]. Several scientists were developed biosensor by modification electrode for many purpose [1], [4], [7], [10]- [17]. Fitriyana and Kurniawan has been reported that polyaniline-invertase-gold nanoparticles modified gold electrode can be used as sucrose detection [18]. ...
Milkfish (Chanos chanos) gelatin was successfully developed as biosensor material. The milkfish bone was obtained from local restaurants in Tarakan, North Borneo, Indonesia. Gelatin was extracted from milkfish bone using acid method at 55°C. Characterization by FTIR showed that milkfish gelatin had similar functional group with commercial gelatin. The gelatin was used as biosensor material for detecting chromium. The gelatin was mixed with carbon in 1:1 ratio to form gelatin/carbon paste modified silver electrode. Electrochem-ical impedance spectroscopy (EIS) analysis of the gelatin/carbon paste modified silver electrode showed a better conductivity than paraf-fin/carbon paste modified silver electrode. Performance of the gelatin/carbon paste modified silver electrode in chromium (III) solution was conducted using cyclic voltammetry technique. Measurement was carried out at-1 V to +1 V with scan rate of 100 mV/s in acid and base condition. The best result was shown by gelatin/carbon paste modified silver electrode. It can detect chromium (III) ions at reduction potential of-0.78 V in alkaline condition. Unspecific responses were observed from silver electrode, paraffin/silver electrode, car-bon/silver electrode, gelatin/silver electrode and paraffin/carbon paste modified silver electrode. This result can be concluded that the milkfish gelatin obtained have a potential to be developed as chromium (III) biosensor.
... Therefore a "cassette" consisting of the desired gene with a promoter and other required elements is constructed before it is delivered to the plant cells. For the selection of transformed cells, selection markers (usually antibiotic markers) are used and reporter proteins may be used for the expression confirmation (Low et al., 2018). Plant cells usually contain three genomes, that is, nuclear, chloroplast, and mitochondrial genomes. ...
... Environmental pollution has contributed to the development of rapid techniques for identifying harmful substances, including biosensors. Biosensors detect small amounts of pollutants in liquids and solids and allow you to monitor the environment in terms of biological and ecological quality (eutrophication, pesticides, toxins) or contamination with organic and inorganic compounds (metals or aromatics) (Ejeian et al., 2018;Salgado et al., 2011). The use of the sub-membrane fraction of photosystem II (PSII) allows the detection of toxic metal cations, including copper (Cu), while other photosynthetic biosensors allow the detection of PbCl 2 and CdCl 2 (Carpentier et al., 1991). ...
... Sensors, alternatively, offer an accurate, fast, and easy solution to monitor water contaminants. The compact designs of sensor instruments have also made it possible for in situ contaminants monitoring, while preventing long-term and often costly analysis in laboratories [15]. ...
... These interactions produce or use ions or electrons that cause a change in the electrical properties of electrolyte solution. The transducer measures the change in electrical current or potential of electrolyte solution and produces electrochemical signal, which is associated with the quantity of analyte of interest in the sample [8,15]. ...
... As a rule, biosensors make it possible to determine the BOD index in the range of 2-300 mgO 2 /dm 3 in a few minutes. At the same time, the correlation coefficient between the BOD values determined using a biosensor and the standard method ranges from 0.6 to 0.98 [4][5][6]. However, a large number of publications regularly published on this topic indicate that characteristics have not yet been obtained that would stop the process of further search for improvements for this analysis. ...
... However, a large number of publications regularly published on this topic indicate that characteristics have not yet been obtained that would stop the process of further search for improvements for this analysis. The most urgent problem for the development of the BOD sensors is to increase the sensitivity of the analysis, since most of the described biosensors do not allow determining BOD in clean surface waters, in which BOD is less than 2 mgO 2 /dm 3 [6,7]. ...
The possibility of the developing a biochemical oxygen demand (BOD) biosensor based on electroactive biofilms of activated sludge grown on the surface of a graphite-paste electrode modified with carbon nanotubes was studied. A complex of microscopic methods controlled biofilm formation: optical microscopy with phase contrast, scanning electron microscopy, and laser confocal microscopy. The features of charge transfer in the obtained electroactive biofilms were studied using the methods of cyclic voltammetry and electrochemical impedance spectroscopy. The rate constant of the interaction of microorganisms with the extracellular electron carrier (0.79 ± 0.03 dm3(g s)−1) and the heterogeneous rate constant of electron transfer (0.34 ± 0.02 cm s−1) were determined using the cyclic voltammetry method. These results revealed that the modification of the carbon nanotubes’ (CNT) electrode surface makes it possible to create electroactive biofilms. An analysis of the metrological and analytical characteristics of the created biosensors showed that the lower limit of the biosensor based on an electroactive biofilm of activated sludge is 0.41 mgO2/dm3, which makes it possible to analyze almost any water sample. Analysis of 12 surface water samples showed a high correlation (R2 = 0.99) with the results of the standard method for determining biochemical oxygen demand.
... Desiccants should be characterized by the possibility of high hydrophilicity and large water sorption capacity. Such a combination enables their efficient use in water desalination [53], water-oil separation [54][55][56][57], wastewater treatment [58][59][60][61][62], environmental disinfections [63][64][65][66][67] or other technological and industrial applications [41,[68][69][70][71]. On the other hand, the most conventional ones, such as silicates, zeolites, aluminophosphates, activated charcoal or recently graphene oxide foams, are often characterized by their relatively high regeneration temperature exceeding 100 C [72]. Therefore, under standard indoor conditions, they cannot release moisture and instead they regenerate, making them unsuitable for standard passive applications, like passive houses, which could operate without the external impacts [73]. ...
... The advantages of MOFs are high surface area, adjustable pore size, pore surface properties, and exceptional adsorption capacity for different gases [59]. However, the adsorption capacity of MOFs is significantly reduced when exposed to gas mixtures. ...
Higher than a standard level, the humidity provides a suitable environment for the pathogenic microorganisms to grow and increases energy consumption for cooling, increasing greenhouse gas emissions. Desiccant air-conditioning (DAC) is an effective method to reduce humidity and energy simultaneously. Conventional desiccants are not suitable for use as a desiccant in building air conditioners, mainly because of high regeneration temperature and other issues such as limited equilibrium capacity and hydrothermal and cyclic instability. Metal-organic frameworks (MOFs) are a novel class of porous crystalline materials without the disadvantages of traditional desiccants. They benefit from a huge surface area and considerable pore-volume, very low framework density, and a high-water uptake capacity. In this review article, we have critically and comprehensively discussed the use of MOFs in heat transformation and air conditioning processes. The reasons for the superiority of MOFs over traditional desiccant materials are also discussed comprehensively. Moreover, since thermal conductivity is a key factor in the heat transfer process, an overview has been made on techniques of measuring the thermal conductivity of MOFs. Eventually, several state-of-the-art MOF-based heat transformation applications are reviewed, including heat storage, heat pumps and different desiccant dehumidifiers.
... As it has been demonstrated in the COVID pandemic, in many fields, there is increasing need for fast and simple to use techniques, assays are expected to evolve toward the quantification of analytes at low concentration range in a short time [14]. ...
... As a first step, different optical densities of the gold-antibody conjugate were tested. As it was already reported [14], it is necessary to use high optical density nanogold-antibody conjugate solutions to get high signals without amplification step. Therefore, the volume of the antibody modified gold nanoparticles was 5.0 μL, whereas the sample volume ranged between 50 and 500 μL. ...
A homogeneous-heterogeneous immunoassay based on the use of antibody modified gold nanoparticles, 5 and 50 nm in diameter, is developed with and without signal amplification. The assays involve the capture of the target analytes in the homogeneous phase and subsequent detection of the immunoreaction product, following a heterogeneous scheme performed on a regular DVD. The analytical approach was evaluated developing multiplexed competitive immunoassays for the determination of residues of the pesticides chlorpyrifos and azoxystrobin as model targets. The results revealed that homogeneous immunocapture strategy improves considerably the assay performance, giving better assay sensitivity when compared to the standard heterogeneous immunoassay format. Under the best conditions, the least detectable level for chlorpyrifos and azoxystrobin were 0.1 μg/L. The immunoassays were also highly selective, showing little or no cross-reactivity with other structurally similar compounds. The immunocapture approach was assessed by the analysis of water. The analytical sensitivity was compared with that of reference chromatographic methods, and recovery results agreed. The good recoveries obtained (mean values ranging between 80% and 125%) make this strategy a suitable screening biosensing methodology for either environmental monitoring or laboratory quantification of pesticide residues without sample treatment in a maximum time of 65 min at lower cost.
... The wastewater treatment plant is embedded with dedicated sensors, and the software can interact seamlessly with each other and with the operator/owner/Government. However to improve the efficiency of industrial wastewater treatment processes, sensors can be used as monitoring and control functions. Bacteria use microbial electrochemical sensors, antibiotics use optical biosensors, and heavy metals use electrochemical sensors [8,9,10,11]. Microscopy, flow cytometry, and spectroscopy are used for micropollutants, toxicity, and trace organic pollutants parameters [12,13]. ...
With the fast development of the global economy and population, there has been an increase in the amount of wastewater and industrial effluents being discharged into rivers and lakes, resulting in deterioration of water quality and a reduction in the availability of freshwater resources. A comprehensive discussion of the topic of Industrial Wastewater Treatment Integrated for Sustainable Green Industry 4.0, including the difficulties and possible solutions that may be encountered along the way, is provided in this article. According to the results of this study, industrial wastewater treatment that uses online/real-time water for quality monitoring and control has shown great promise in terms of quality monitoring and control when utilizing online/real-time water. Implementing such a system in industrial wastewater treatment may offer an early warning system for poor treatment while increasing the quantity and quality of the end product, both of which are desired outcomes.
... The enhancement of sensitivity and selectivity is greatly achieved by incorporating carbon-based nanomaterials (graphene oxide, carbon nanotubes, soot) or metallic nanoparticles (gold (Au), silver (Ag), platinum (Pt) in the construction of electrochemical. These nanomaterials are crucial in the facile fabrication of electrodes which determines stability, conductivity, and signal intensity for sustainable commercial application of biosensors (Ejeian et al., 2018;Torrinha et al., 2020;Wu et al., 2022). The sensor technology approach presents an excellent scope of portable and simple biosensor devices which are cost-effective with versatility and practical options and reduced sample volumes and reagents consumption. ...
The influx of emerging, prescribed, and FDA approved pharmaceutical contaminants (PCs) in the environment is continuously affecting human health and human cycle (even at trace amount) via contaminating water and aquatic life. Among them, non-degradable water-soluble residues which have been integrated with water streams and groundwater is a serious concern and is now a focus of United Nation's Sustainable Development Goals 2030. In this direction, the removal and eradication of PCs from wastewater is challenging but seems manageable via selective detection and efficient remediation using nano-enabled functional systems. To explore this field well for covering gaps, this article is an attempt to explain wide variety of emerging pharmaceutical contaminants, related bio-toxicity, health risks, detection techniques, and approaches of remediation. With the aim of health and environmental management, selective detection and eradication of PCs simultaneously is recommended using nano-system of tuneable properties managed via adopting green approaches. Significant efforts are being made to achieve 1) detection of PCs at very low level (ppb) needed for early-stage water diagnostics and 2) eradicating PCs using stimuli-responsive catalysis. In both the cases, the design and development of electro-active nano-systems of desired feature is key requirement for developing acceptable and affordable health and environmental management strategies. The outcomes of this article will encourage scholars to develop novel and efficient nano-systems capable of detection and eradication of targeted PCs to produce clean and healthy water for everyone.
... For example, Rusiñol et al. (2020) used metagenomics to detect Pseudomonas, Enterobacter cloacae, Hepatitis E virus and Naegleria spp in various irrigation water sources in Barcelona, Spain. Other molecular approaches such as fluorescent in situ hybridization, amplified ribosomal DNA restriction analyses, analysis of functional genes using RT-PCR, estimation of biomass, proteomics and metabolomics have also been explored (Ejeian et al., 2018;Xie et al., 2019). ...
Contaminated irrigation water is among many potential vehicles of human pathogens to food plants, constituting significant public health risks especially for the fresh produce category. This review discusses some available guidelines or regulations for microbiological safety of irrigation water, and provides a summary of some common methods used for characterizing microbial contamination. The goal of such exploration is to understand some of the considerations that influence formulation of water testing guidelines, describe priority microbial parameters particularly with respect to food safety risks, and attempt to determine what methods are most suitable for their screening. Furthermore, the review discusses factors that influence the potential for microbiologically polluted irrigation water to pose substantial risks of pathogenic contamination to produce items. Some of these factors include type of water source exploited, irrigation methods, other agro ecosystem features/practices, as well as pathogen traits such as die-off rates. Additionally, the review examines factors such as food safety knowledge, other farmer attitudes or inclinations, level of social exposure and financial circumstances that influence adherence to water testing guidelines and other safe water application practices. A thorough understanding of relevant risk metrics for the application and management of irrigation water is necessary for the development of water testing criteria. To determine sampling and analytical approach for water testing, factors such as agricultural practices (which differ among farms and regionally), as well as environmental factors that modulate how water quality may affect the microbiological safety of produce should be considered. Research and technological advancements that can improve testing approach and the determination of target levels for hazard characterization or description for the many different pollution contexts as well as farmer adherence to testing requirements, are desirable.
... The use of porous silicon (PSi) layer, as a based substrate, to sense chemical and gas substances is favored due to its low-cost and easy preparation [1]. The use of porous silicon SERS metallic nanostructure sensing devices to detect chemicals and pesticides content at ultra-low aquatic concentrations is very promising to monitor environmental pollution [2]. The PSi pores, trenches, mud, and pillars like morphologies have different structural and optical details and different specific surface area (S.S.A.) [3]. ...
Fixed laser pulse duty cycle at 20% using short laser wavelength (405 nm) at different values of laser power density (300–600 mW/cm2) were used to form Si nano-columns as based SERS layer. The idea was to synthesize SERS devices with excellent reproducibility and high enhancement factor to detect ultra-low residence of chlorpyrifos pesticide. The results indicated that the morphological aspects of silicon nano-columns layer and; hence, the performance of SERS devices could be well-regulated through the adjustment of laser power density. The SERS detection of ultra-low chlorpyrifos concentrations displayed an excellent reproducibility with less than 5% error. The highest chlorpyrifos enhancement factor (EF = 1.1 × 106) and minimum detection limit (LOD = 22 × 10−8 M) were obtained from high altitude Si nano-columns; partly populated with three dimensions AuNPs layer, and the use of 500mW/cm2 laser power density.
... Biosensors are easy-to-handle, simple, cost-effective, reliable and provide a fast technique for monitoring various heavy metals such as Hg 21 in contaminated water (Ejeian et al., 2018). Biosensors can provide both quantitative or qualitative information using biochemical receptors or biological recognition elements (Saidur et al., 2017). ...
Purpose-This information will be useful in the selection of materials and technology for the detection and removal of mercury ions at a low cost and with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. Design/methodology/approach-Different nano-and bio-materials allowed for the development of a variety of biosensors-colorimetric, chemiluminescent, electrochemical, whole-cell and aptasensors-are described. The materials used for their development also make it possible to use them in removing heavy metals, which are toxic contaminants, from environmental water samples. Findings-This review focuses on different technologies, tools and materials for mercury (heavy metals) detection and remediation to environmental samples. Originality/value-This review gives up-to-date and systemic information on modern nanotechnology methods for heavy metal detection. Different recognition molecules and nanomaterials have been discussed for remediation to water samples. The present review may provide valuable information to researchers regarding novel Mercury ions detection sensors and encourage them for further research/development.
... This type of materials has found many applications e.g. in medicine [1] and in the production of single-use bioplastics [2]. Biopolymers can also be used to produce enzymatic biosensor matrices, where they fulfill two important roles: immobilizing the enzyme on the detection part of the biosensor and improving the detection properties of biosensors [3]. ...
The biopolymer matrix synthesized from epoxidized soybean oil (AESO) and vanillin dimethacrylate (VDM) in a molar ratio of 1:1 was investigated by the Positron Annihilation Lifetime Spectroscopy (PALS) in the presence of pure water, saline solution, and water contaminated with xenobiotics from a reservoir. The main aim of the research is the construction of a biosensor with a biopolymer matrix for the detection of trace water pollution with xenobiotics, which are carcinogenic and have a negative impact on the human endocrine system. These substances may come from the pharmaceutical industry, households, and are used as plant protection products or food additives. The measurements show that the presence of ions and pollution in water causes the elongation of the absorption process into the matrix. The performance of the biosensor will therefore correlate with the level of ion concentration and pollution.
... The World Health Organization (WHO) has established different guidelines for the safety of water resources and managing of health risks and hazards associated with water and wastewater systems (Organization, 2001). Therefore, numerous research efforts have been devoted to developing innovative technologies for monitoring, sanitation, and treating water and wastewater resources (Ejeian et al., 2018;Zhao et al., 2019b). According to the declaration of the World Summit on Food Security, healthy societies should provide easy accessibility to sufficient, safe, and nutritious food for all people (Grainger, 2010). ...
The global health status is highly affected by the growing pace of urbanization, new lifestyles, climate changes, and resource exploitation. Modern technologies pave a promising way to deal with severe concerns toward sustainable development. Herein, we provided a comprehensive review of some popular biotechnological advancements regarding the progress achieved in water, food, and medicine, as the most substantial fields related to public health. The emergence of novel organic/inorganic materials has brought about significant improvement in conventional water treatment techniques, anti-fouling approaches, anti-microbial agents, food processing, biosensors, drug delivery systems, and implants. Particularly, a growing interest has been devoted to nanomaterials and their application for developing novel structures or improving the characteristics of standard components. Also, bioinspired materials have been widely used to improve the performance, efficiency, accuracy, stability, safety, and cost-effectiveness of traditional systems. On the other side, the fabrication of innovative devices for precisely monitoring and managing various ecosystem and human health issues is of great importance. Above all, exceptional advancements in designing ion-selective electrodes (ISEs), microelectromechanical systems (MEMs), and implantable medical devices have altered the future landscape of environmental and biomedical research. This review paper aimed to shed light on the wide-ranging materials and devices that have been developed for health applications and mainly focused on the impact of nanotechnology in this field.
... The ability to continuously monitor concentration levels of key molecules in dynamic biological systems would offer exciting opportunities in applications such as fundamental biological research 1-5 , studies on organs-on-a-chip 6,7 , monitoring of patients in critical care [8][9][10][11][12] , and monitoring of industrial processes 13,14 and bioreactors 15,16 as well as ecological systems [17][18][19] . Continuous monitoring sensors are commercially available for glucose, but glucose is present at high concentrations (millimolar) 20 . ...
There is a need for sensing technologies that can continuously monitor concentration levels of critical biomolecules in applications such as patient care, fundamental biological research, biotechnology and food industry, as well as the environment. However, it is fundamentally difficult to develop measurement technologies that are not only sensitive and specific, but also allow monitoring over a broad concentration range and over long timespans. Here we describe a continuous biomolecular sensing methodology based on the free diffusion of biofunctionalized particles hovering over a sensor surface. The method records digital events due to single-molecule interactions and enables biomarker monitoring at picomolar to micromolar concentrations without consuming any reagents. We demonstrate the affinity-based sensing methodology for DNA-based sandwich and competition assays, and for an antibody-based cortisol assay. Additionally, the sensor can be dried, facilitating storage over weeks while maintaining its sensitivity. We foresee that this will enable the development of continuous monitoring sensors for applications in fundamental research, for studies on organs on a chip, for the monitoring of patients in critical care, and for the monitoring of industrial processes and bioreactors as well as ecological systems.
... This causes a change in the electrical properties of the electrolyte solution. The change in the electrical current or potential of the electrolyte solution is measured using functionalized electrodes, which generate an electrical signal that is correlated to the amount of target analyte in the test sample [23], [24]. Many recent studies have shown that electrochemical biosensors can be utilized for SARS-CoV-2 diagnosis [25]. ...
COVID-19 caused by the transmission of SARS-CoV-2 virus taking a huge toll on global health and caused life-threatening medical complications and elevated mortality rates, especially among older adults and people with existing morbidity. Current evidence suggests that the virus spreads primarily through respiratory droplets emitted by infected persons when breathing, coughing, sneezing, or speaking. These droplets can reach another person through their mouth, nose, or eyes, resulting in infection. The "gold standard" for clinical diagnosis of SARS-CoV-2 is the laboratory-based nucleic acid amplification test, which includes the reverse transcription-polymerase chain reaction (RT-PCR) test on nasopharyngeal swab samples. The main concerns with this type of test are the relatively high cost, long processing time, and considerable false-positive or false-negative results. Alternative approaches have been suggested to detect the SARS-CoV-2 virus so that those infected and the people they have been in contact with can be quickly isolated to break the transmission chains and hopefully, control the pandemic. These alternative approaches include electrochemical biosensing and deep learning. In this review, we discuss the current state-of-the-art technology used in both fields for public health surveillance of SARS-CoV-2 and present a comparison of both methods in terms of cost, sampling, timing, accuracy, instrument complexity, global accessibility, feasibility, and adaptability to mutations. Finally, we discuss the issues and potential future research approaches for detecting the SARS-CoV-2 virus utilizing electrochemical biosensing and deep learning.
... An important subclass of POC is biological devices that use biomolecules, such as antibodies and antigens in immunoassays, DNA strands, and enzymes to achieve a specific interaction between substrate and analyte [5]. Several applications in food safety [6,7], environmental management [8,9], agriculture [10], pharmaceuticals [11], food compositional analysis [12], and medical care have been reported since rapid and reliable sensing of human biomarkers can lead to faster diagnosis and early medical intervention [13]. ...
The use of biological components in the development of new methods of analysis and point-of-care (POC) devices is an ever-expanding theme in analytical chemistry research, due to the immense potential for early diagnosis of diseases and monitoring of biomarkers. In the present work, the evaluation of an electrochemical microfluidic device based on the immobilization of horseradish peroxidase (HRP) enzyme into chemically treated cotton threads is described. This bioreactor was used as a channel for the build of the microfluidic device, which has allowed to use of a non-modified screen-printed electrode (SPE) as an amperometric detector. Cotton threads were treated using citric acid, and the immobilization of HRP has been performed by EDC/NHS crosslinking, connecting amine groups of the enzymes to carboxylic acids in the cellulosic structure. For the analytical evaluation, an amperometric assay for hydrogen peroxide detection was performed after the injection of H2O2 and hydroquinone (HQN) concomitantly. The enzymatic reaction consumes H2O2 leading to the formation of O-quinone, which is readily reducible at non-modified SPE. Several experimental parameters related to enzyme immobilization have been investigated and under the best set of conditions, a good analytical performance was obtained. In addition, the threads were freezer-stored and, after 12 weeks, 84% of hydrogen peroxide sensitivity was maintained, which is very reasonable for enzyme-based systems and still offers good analytical precision. Therefore, a simple and inexpensive microfluidic system was reported by crosslinking carboxylic groups to amine-containing macromolecules, suggesting a new platform for many other protein-based assays.
... Water is an essential part of all the living beings on earth, but in recent times, anthropogenic activities have increased immensely, which are the major causes of water pollution, disturbing the marine biodiversity and leading to a tremendous water shortage [1][2][3]. Even though the chemicals and water nutrients are crucial to our day-to-day lives, the excessive wastewater [26][27][28]. ...
The release of chemicals and microorganisms from various sources, such as industry, agriculture, animal farming, wastewater treatment plants, and flooding, into water systems have caused water pollution in several parts of our world, endangering aquatic ecosystems and individual health. World Health Organization (WHO) has introduced strict standards for the maximum concentration limits for nutrients and chemicals in drinking water, surface water, and groundwater. It is crucial to have rapid, sensitive, and reliable analytical detection systems to monitor the pollution level regularly and meet the standard limit. Electrochemical biosensors are advantageous analytical devices or tools that convert a bio-signal by biorecognition elements into a significant electrical response. Thanks to the micro/nano fabrication techniques, electrochemical biosensors for sensitive, continuous, and real-time detection have attracted increasing attention among researchers and users worldwide. These devices take advantage of easy operation, portability, and rapid response. They can also be miniaturized, have a long-life span and a quick response time, and possess high sensitivity and selectivity and can be considered as portable biosensing assays. They are of special importance due to their great advantages such as affordability, simplicity, portability, and ability to detect at on-site. This review paper is concerned with the basic concepts of electrochemical biosensors and their applications in various water quality monitoring, such as inorganic chemicals, nutrients, microorganisms’ pollution, and organic pollutants, especially for developing real-time/online detection systems. The basic concepts of electrochemical biosensors, different surface modification techniques, bio-recognition elements (BRE), detection methods, and specific real-time water quality monitoring applications are reviewed thoroughly in this article.
... Thus, biosensors based on immobilized bacteria provide the opportunity for real-time water quality monitoring. The application of microbial cells in water biosensing is a rapidly growing field [5][6][7][8]. Bacteria may be easily immobilized without loss of metabolic activity, providing durable and inexpensive sensing elements. The advantage of nitrifying bacteria is the high consumption of oxygen in their metabolism (especially during ammonium oxidation), with a simultaneous slight increase in biomass which results from the low energy efficiency of the nitrification processes. ...
Sensitive detection with cell biosensors requires optimization of their working conditions and standardization of the response in variable physicochemical conditions. The introduction of an analyte to a sensor, which contributes to this variability, may account for the modeling of microbial metabolism. We constructed a multiparameter model of a water toxicity sensor of Automatic Biodetector for Water Toxicity (ABTOW), developed by our group and based on nitrifying bacteria. The model describes the kinetics of nitrification as a function of four orthogonal parameters: temperature, pH, oxygen and ammonium concentration. Furthermore, we characterized the signal-to-noise ratio (SNR) of the ABTOW readout as a function of these parameters. Thus, a region of parameter space corresponding to optimal ABTOW operation is identified and its sensitivity quantified. We applied the model to describe the ABTOW performance in non-equilibrium conditions produced by rapid changes in pH and temperature. In sum, the model based on four physicochemical parameters describes changes in the biosensor’s activity, the biological element of which are nitrifying bacteria characterized by simple chemolithoautotrophic metabolism. The description of reaction kinetics through multiparameter modeling in combination with stability analysis can find application in process control in biotechnology, biodetection and environmental research.
... Optical biosensor is analytical technique which can be used for monitoring pollutants without using any extensive sample or label-free preparation (Long, Zhu, & Shi, 2013;Singh, 2017). It is based on immunoanalytical technique which required fluorescent-labeled antibodies (Ejeian et al., 2018). It has huge advantage over conventional methods such as high frequency, high specificity, real time, cost-effectiveness, and highly sensitive for monitoring of various drugs, toxins, and pathogenic bacteria in wastewater (Bae, Oh, Lee, Lee, & Choi, 2004;Lazcka, Campo, & Muñoz, 2007;Dar, Bandh, Kamili, Nazir, & Bhat, 2013;Long et al., 2013;Singh, 2017). ...
Water scarcity due to increasing water pollution is the main ecological threat that we are facing today. It has been reported that approximately 71% (4.3 billion) of people have to face water scarcity in a few months of the years globally. Due to the shortage of freshwater resources, there is a simultaneous rise in the water demand, particularly in dry areas with low precipitation. Previously, numerous strategies have been developed for the treatment of wastewater. Conventional detection methods are costly and are not efficient and sensitive in tracing various pollutants in wastewater. Biosensors have drawn considerable attention in this field because of their highly sensitive, selective, cost-effective, and on-site detection capability. The present chapter provides a comprehensive overview of various classes of biosensors that have been used for monitoring organic, physical, and chemical pollutants. Various limitations and future prospects of the strategies involving biosensing have also been discussed.
... The application of pesticides in large amounts pollutes the soil and water, which possesses harmful effects on living beings. Novel nanosensors are developed to detect pesticides, heavy metal ions, and dyes from the water [67][68][69][70][71]. ...
Nanomaterials have shown immense potential for their versatile applications in various sectors like medicine, healthcare, food sector, environment, agriculture, electronics, and pharmaceutics due to their unique and tunable physicochemical properties attributed to their small sizes. Recently nanomaterials have garnered foremost interest in agricultural applications due to constructive results of various studies showing significantly better crops growth/yield as compared to traditional fertilizers and pesticides. Besides, nanomaterials have shown encouraging results to deal with problems associated with conventional fertilizers, such as low nutrient usage efficiency and unregulated nutrient release with no precise control on the nutrients delivery. Moreover, nanomaterials have positively impacted plants growth attributing to higher chlorophyll content in leaves, increased root/shoot lengths, and better stress tolerance. Furthermore, nanomaterials are extremely capable of disease detection in plants and soil remediation. In this review, we have attempted to provide the readers with a complete overview of nanomaterials in agriculture by implementing the ideas of precision farming. Hereby, we have deliberated the development of nanomaterials in agriculture in the form of nanofertilizers, nanopesticides and nanosensors for sustainable growth in crops productivity, quality and protection. We have also illuminated the possibility of integrated farm management via soil remediation using nanotechnology. Finally, we have explicated limitations and possible improvements of nanomaterials for sustainable agricultural applications.
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... 177,180,181 Additionally, enzyme-based and microorganism-based electrochemical/ optical biosensors suffer from low signal outputs in the water with low conductivity (e.g., river and drinking water), 182 and require a large sensor surface area and additional analyte solution to attain usable response magnitudes. 183 Moreover, the decline of metabolic activities and the inactivation of microbial cells result in rapid deterioration of signal intensity and short lifetime of bioreceptors for LTCM. To address this challenge, recombinant enzymes or genetically modified "super bacteria" that can survive in WW could be developed as the recognition elements in the construction of highly stable biosensors. ...
... Higher end optical techniques such as surface plasmon resonance (SPR) [127,128] and resonant mirror [129,130] have been reported to be sensitive and selective enough to detect virus detection in turbid samples. Functionalized metal nanomaterials such as gold nanoparticles can be used in both colorimetry [131] and Raman spectroscopy [132] to further enhance the sensitivities of these biosensors. While optical biosensors show a lot of potential in terms of sensitivities, these high-end systems are expensive both to purchase and maintain, making it less practical to be implemented in low-income communities. ...
The discovery of SARS-CoV-2 virus in the water bodies has been reported, and the risk of virus transmission to human via the water route due to poor wastewater management cannot be disregarded. The main source of the virus in water bodies is the sewage network systems which connects to the surface water. Wastewater-based epidemiology has been applied as an early surveillance tool to sense SARS-CoV-2 virus in the sewage network. This review discussed possible transmission routes of the SARS-CoV-2 virus and the challenges of the existing method in detecting the virus in wastewater. One significant challenge for the detection of the virus is that the high virus loading is diluted by the sheer volume of the wastewater. Hence, virus preconcentration from water samples prior to the application of virus assay is essential to accurately detect traceable virus loading. The preparation time, materials and conditions, virus type, recovery percentage, and various virus recovery techniques are comprehensively discussed in this review. The practicability of molecular methods such as Polymer-Chain-Reaction (PCR) for the detection of SARS-CoV-2 in wastewater will be revealed. The conventional virus detection techniques have several shortcomings and the potential of biosensors as an alternative is also considered. Biosensing techniques have also been proposed as an alternative to PCR and have reported detection limits of 10 pg/μl. This review serves to guide the reader on the future designs and development of highly sensitive, robust and, cost effective SARS-CoV-2 lab-on-a-chip biosensors for use in complex wastewater.
With the rapid population growth, the world is witnessing an ever-increasing demand for energy and natural resources. Consequently, soil, air, and water are polluted with diverse pollutants, including heavy metals (HM). The detection of heavy metals is necessary to remediate them, which is achieved with biosensors. Initially, these HM were detected using atomic absorption spectroscopy (AAS), emission spectroscopy, mass spectrometry, gas chromatography etc., but these were costly and time consuming which further paved a way for microbe-based biosensors. The development of genetic circuits for microbe-based biosensors has become more popular in recent years for heavy metal detection. In this review, we have especially discussed the various types of genetic circuits such as toggle switches, logic gates, and amplification modules used in these biosensors as they are used to enhance sensitivity and specificity. Genetic circuits also allow for rapid and multiple analyte detection at the same time. The use of microbial biosensors for the detection of HM in the soil as well as the water is also described below. Although with a higher success rate than classical biosensors, these microbial biosensors still have some drawbacks like bioavailability and size of the analyte which are needed to be addressed.
A nanohybrid of zinc oxide and biochar (ZnO/BC) with high conductivity was green synthesized using a simple hydrothermal method, and utilized for the sensitive detection of bisphenol A (BPA) by coating the nanohybrid film on an electrode of glassy carbon. The ZnO/BC presented greatly improved electrocatalytic performance and electron transfer ability compared to the zinc oxide and biochar. The ZnO/BC film-coated electrode could detect the BPA in aqueous solution within 3 min while neglected interference from higher concentrations of regularly existing ions and similar concentrations of estradiol (E2), phenol, dichlorophenol (DCP), and ethinylestradiol (EE2). Under optimal conditions, the linear range of BPA detection was 5 × 10−7~1 × 10−4 mol/L, with a detection limit of 1 × 10−7 mol/L, and the detection sensitivity was 92 mA/M. In addition, the ZnO/BC electrode could detect BPA in a real water sample with good signal recovery. This electrode, with the advantages of an easy preparation, low cost, and fast response time, could be potentially applicable for environmental monitoring.
Coastal zones are critically important ecosystems that are closely tied to human activities, such as tourism, urbanization, transport, and aquaculture. However, managing and monitoring sea water in the coastal areas is often challenging due to the diversity of the pollution sources. Traditional approaches of onsite measurement and surveys have limitations in terms of cost, efficiency and productivity compared with modern remote sensing methods, particularly for larger and longer observations. Optical remote sensing imagery has been proven to be a good data source for water quality assessment in general and for seawater studies in particular with the use of advanced techniques of data processing such as machine learning (ML) algorithms. However, optical remote sensing data also have their own disadvantages as they are much affected by climatic conditions, atmospheric gas and particles as a source of noise in the data. This noise could be reduced, but it
is still unavoidable. This study aims to model seawater quality parameters (total suspended solids (TSS), chlorophyll-a (chla), chemical oxygen demand (COD), and dissolved oxygen (DO)) along a 134 km sea coastal area of the Binh Dinh province by applying the current robust machine learning models of decision tree (DT), random forest (RF), gradient boosting regression (GBR), and Ada boost regression (ABR) using Sentinel-2 imagery. To reduce the atmospheric effects, we conducted onsite
measurements of sea surface reflectance (SSR) using the German RAMSES-TriOS instrument for calibration of the Sentinel-2 level 2A data before inputting them to the ML models. Our modeling results showed an improvement of the model accuracy using calibrated SSR compared with the original Sentinel-2 level 2A SSR data. The RF predicted the most accurate seawater quality parameters compared with in situ field-measured data (mean R2 = 0.59 using original Sentinel-2 level 2A SSR and
R2 = 0.70 using calibrated SSR). The chla was the most precise estimate (R2 = 0.74 when modelled by the RF model) flowing by DO, COD and TSS. In terms of seawater quality estimation, this accuracy is at a good level. The results of the seawater quality distributions were strongly correlated with coastal features where higher values of TSS, chla, COD, and DO are near the river mouths and urban and
tourist areas. These spatial water quality data could be extremely helpful for local governments to make decisions when the modelling is continuously conducted (using big data processing), and it is highly recommended for more applications
Worldwide, environmental pollution is gradually expanding. The most contaminated natural resources are air, water, and land, implying that new techniques are essential to encounter this challenge. Phytonanotechnology is one of the cutting-edge techniques for air, water, and soil remediation with excellent benefits when compared to conventional pollutant removal methods. This chapter highlights the field of nanotechnology with phytoremediation. Both are useful to deliver eco-friendly methods that enhance human well-being by removing pollutants. Also, various processes of bioextract mediated synthesis of nanomaterials are explored for phytobial remediation of organic and inorganic pollutants. In order to enhance the removal of environmental contaminants, raise water quality and safeguard human and environmental well-being, phytonanotechnology has to be used. A significant aspect of the modern field of ecological engineering is phytoremediation, it uses the plants to control and normalize pollution of air, water, and soil. Owing to the dependency on recycling of nutrients using sunlight, most applications are inexpensive. As it requires large land areas and longer treatment time, the treatments are in general limited for shallow water zones. For a variety of waste remediation, those generally present in low concentrations which are not acutely phytotoxic, applications for wetlands, tree plantations, crops, and grasslands are successful. However, using the basic concepts of ecological engineering, very few phytoremediation methods have been designed for environmental sustainability.
Antibiotics used in humans and farmed animals are an essential source of water and soil contamination. Ampicillin is a micropollutant commonly found in water, sludge, food, flora, and fauna. However, the methods used for its detection in environmental samples are often complicated and expensive. Therefore, developing more straightforward strategies to detect well-known target antibiotics is necessary. In this context, enzyme-based detection methods have been demonstrated to be selective, sensitive, rapid, and relatively simple. In this study, a fluorescent byproduct from the ampicillin oxidation using Chloroperoxidase (CPO) enzyme was used as a pointer compound to determine ampicillin concentration in environmental water samples. We oxidized 80% ampicillin for 1h, producing a fluorescent compound with m/z 274.2517. A response surface methodology (RSM) based on a central composite design (CCD) was used to evaluate and optimize the effects of hydrogen peroxide, enzyme concentration, and time as independent variables on the maximum fluorescence signal as the response function. The methodology proposes to build a calibration curve that relates the initial concentration of ampicillin with fluorescence intensity after the reaction with CPO, which helps detect ampicillin in the concentration range from 0.035 to 40 μM, with a limit of detection of 0.026 μM. The application of the method to fortified environmental water samples allowed percentages of recovery from 86 to 140%. The formation of the fluorescent compound was not affected by the presence of salts commonly found in wastewater; however, it was affected by other antibiotics. The proposed methodology was tested in the context of water from water bodies, urban, and WWTP effluents.
Contamination of water is a burning issue of modern civilization, and the issue has been an ever-increasing concern in the present global situation. The accessibility of fresh water has been constantly diminishing in recent years although the necessity of water, especially in the dry and semi-dry climate, is growing. This associated with territory exhaustion causes scarcity of water and results in declining oceanic biodiversity. Monitoring contaminants in wastewater spillovers has rendered imperative, and it has been crucial to recognize regions of water contamination and take appropriate measures for remedial action. The development of material science and nanotechnology, particularly the innovation of biosensors based on nanomaterials, has paved the way to detect bioanalytes with very high sensitivity, lower detection limit, and improved selectivity replacing the conventional methods and strategies, which more often suffer from poorer sensitivity and consumption of time. The rapid expansion of nanomaterials-based biosensing devices has generated a surge of interest due to their high affectability, selectivity, dependability, simplicity, low cost, and consistent response. This chapter gives a general overview of the development of recent nanobiosensors, focusing on their use in wastewater management.
Pollutants have become the global concern for which there is an intense demand for a quick, reliable, and sustainable system for their determination in the environment and agricultural land. Quantitative analytical tools such as chromatography and spectroscopy, albeit precise and accurate, expensive, requires experienced technician, complicated sample preparation steps, and difficult to assess at high frequencies in real-time. To overcome the issues, nanoparticle-based biosensors are considered as a potential tool to detect both biotic and abiotic toxins. With headways in nanotechnology, numerous specialists have utilized the one-of-a-kind properties of nanomaterials (counting a high surface-area-to-volume proportion) to foster efficiency and sensitivity in detection techniques. Nanomaterials have enabled us to design devices at the microscale level, prompting fast, versatile, and sensitive microorganism symptomatic frameworks that can recognize airborne microbes in clinics, air vents, and planes and bioterrorism in open spaces. Hence, this chapter gives an overview of the usage of nanobiosensors in the detection of contaminants. Further, the present scenario and future scope are also discussed in the development of novel detection devices, and their advantages over other environmental monitoring methodologies.
KeywordsBiosensorsNanoparticlesContaminantsPathogens
Nature contains technologies that will make our lives easier. Hundreds of examples of biomimetics are now found in our daily life, one of such is biosensors. Biosensors studies have been continuously developing in recent years. The increase and widespread use of these studies are due to the fact that biosensors give correct results in many application areas in a short time. Nanoparticle-based biosensors are preferred in environmental monitoring because they are very sensitive and fast. There are high levels of potential analyte in air, water, and soil. In addition to current pollution situations, they are potential uses for farming, horticulture, and mining nanobiosensors. Nanobiosensors can detect oil spills and radioactive contamination in groundwater, as well as the concentration of toxic wastes, carcinogens, and microorganisms that get into drinking water. This chapter presents information on the use of biomimetically developed nanobiosensors in the environment.
KeywordsBiomimeticEnvironmental monitoringNanoparticle
There have been major advancements in the fields of science and technology, one of them is nanotechnology. Wastewater is a serious issue in society, various methods have been used to tackle this problem. One approach is by use of nanobiosensors are being utilized in the treatment of wastewater because of their advantages like high absorption capability, better membrane filtration, and high monitoring output. Moreover, biosensors are classified into various types which have their associated advantages. This chapter brings an extensive literature collation that gives a systematic understanding of biosensors, nanotechnology, and the utilization of nanobiosensors to manage wastewater treatment with its future aspects.
The wastewater quality index (WWQI) is one of the most significant methods of presenting meaningful values that reflect a fundamental characteristic of wastewater. Therefore, this study was performed to develop a prediction approach using WWQI for a regional wastewater treatment plant (WWTP) in Melaka, Malaysia. The regional system of WWTP provides a huge amount of registered data due to the many parameters recorded daily. A multivariate statistical analysis approach was applied to analyze the database. In this approach, principal component analysis (PCA) was used to reduce the dimensionality of datasets obtained from the field municipal WWTP, and multiple linear regression (MLR) was used to predict the performance of WWQI. Seven principal component analyses were derived where the eigenvalue was above 1.0, explaining 71.01% of the variance. A linear relationship was observed (R2 = 0.85), p-value < 0.05, and residual values were uniformly distributed above and below the zero baselines. Therefore, the coefficients of the WWQI model are directly dependent on influent biological oxygen demand (BOD), effluent BOD, influent chemical oxygen demand (COD), and effluent COD values. The experimental results showed that the model performed well and can be used to predict WWQI for each WWTP individually and provide better achievements.
Nanoplasmonic sensing relies on enhanced electromagnetic fields at the vicinity of nanostructured metal surface to detect molecules at ultra-low concentrations. The EM enhancements are strongly pronounced at junctions between adjacent nanostructures resulting in gap hot-spots. EM enhancements at these hot-spots increase non-linearly as a function of gap distances down to sub-10 regime. Analyte present at these gaps can leverage these EM enhancements, resulting in ultra-high sensitivity in detection. However, such confining gaps affect the ability of large analytes such as biomolecules to enter and thereby leverage EM fields within the gaps. This presents spatial needs to enhance EM fields at odds with those for accommodating biomolecular interactions. This thesis demonstrates the rational design of array configurations that allows the EM hotspots to be better leveraged by the reporter of biomolecular binding event. The thesis uses molecular self-assembly based approach to fabricate reproducible plasmonic nanoarrays on full wafers. Multiple parameters are considered including the dimension, shape, and density of hotspots, surface functionalization, and the choice of substrates, to demonstrate quantitative detection of molecules down to picomolar concentrations.
Facile, efficient, and inexpensive biosensing systems are in high demand for biomedical test. In recent years, numerous smartphone-based biosensing systems have been developed to match demand for biomedical test in source-limited environment. However, application of these smartphone-based biosensing systems was limited because of performance gap between the smartphone-based systems and commercial plate readers. In this study, we have developed a smart tablet–phone-based colorimetric plate reader (STPCPR) with intelligent and dynamic light modulation for broad-range colorimetric assays. The STPCPR allows controllable modulation of exciting light in three different color channels that is lack in conventional smartphone-based system. Using optimized exciting modulation, the STPCPR shows higher sensitivities, lower detection limits, and broader detection ranges in test of pigments, proteins, and cells when compared to conventional plate readers and smartphone-based system. Therefore, the developed STPCPR can serve as an ideal next-generation smartphone-based biosensing system for point-of-care colorimetric test in diverse biomedical applications in source-limited environment.
Density functional theory calculations were performed for investigating the effect of doping the Ni atom on the sensing capability of a B24N24 nanocluster ((BN)24) in detecting the carbonyl fluoride (CF) gas. We predicted that the interaction of pristine (BN)24 with CF was a physisorption, and the sensing response (SR) of (BN)24 was 5.1. The adsorption energy of CF changed from -4.9 to -21.4 kcal/mol after doping the Ni atom. Also, the corresponding SR increased significantly to 77.8, indicating that the Ni transition metal significantly increased the sensitivity of the nanocluster. It was shown that the [email protected](BN)24 may selectively detect the CF gas among O2, CF4, SiF4, C2F6, and HF gases. Our theoretical results further supported the fact that the [email protected] nano-structures have practical applications.
Truncated 1D photonic crystals-based biosensors with aperiodic defects under the Kretschmann configuration are investigated for sensing the refractive index changes in an aqueous solution polluted with blood components like plasma (n=1:35). The aperiodic defect cells are three types of Fibonacci sequences (S2, S3, and S4) made of two Dirac semimetal and dielectric materials. Dirac semimetal materials have considerably tunable permittivities and conductivities and evidence have shown that light-matter coupling is stronger than previously known materials like graphene. The Bloch surface waves and defect modes are the results of breaking the periodicity in an ordinary 1D photonic crystal that appeared in the photonic band gaps. The influence of the irregular, periodic defect layer on the hybridization of the defect and surface modes and the performance of the proposed biosensors are investigated by using the well-known transfer matrix method. The effect of the defect layer thicknesses is also taken into account. Plotting the electric field profile shows that the modes in the crossing region change their roles and those following the slope of the modes in the defectless structure have better sensing performance than farther ones. In addition, results show that the figure of merit of the structures (N′=2, N=4) using the aperiodic defect with mentioned Fibonacci sequences (FOM(S3)=525 and FOM(S4)=508) is considerably better than those made of periodic defects (FOM(S2)=406).
Abiotic stresses of various chemical contamination of physical, inorganic, organic and biotoxin origin and biotic stresses of bacterial, viral, parasitic and fungal origins are the significant constraints in achieving higher aquaculture production. Testing and rapid detection of these chemical and microbial contaminants are crucial in identifying and mitigating abiotic and biotic stresses, which has become one of the most challenging aspects in aquaculture and culture-based fisheries. The classical analytical techniques, including titrimetric methods, spectrophotometric, mass spectrometric, spectroscopic, and chromatographic techniques, are tedious and sometimes inaccessible when required. The development of novel and improved bioanalytical methods for rapid, selective and sensitive detection is a wide and dynamic field of research. Biosensors offer precise detection of biotic and abiotic stressors in aquaculture and culture-based fisheries within no time. This review article allows filling the knowledge gap for detection and monitoring of chemical and microbial contaminants of abiotic and biotic origin in aquaculture and culture-based fisheries using nano(bio-) analytical technologies, including nano(bio-)molecular and nano(bio-)sensing techniques.
Worldwide growing concerns about water contamination and pollution have increased significant interest in trace level sensing of variety of contaminants. Thus, there is demand for fabrication of low cost, miniaturised sensing device for in-situ detection of contaminants from the complex environmental matrices capable of providing selective and sensitive detection. Molecularly imprinted polymers (MIPs) has portrayed a substantial potential for selective recognition of various toxicants from a variety of environmental matrices, thus widely used as artificial recognition element in the electrochemical sensors (ECS) owing to their chemical stability, easy and low cost synthesis. The combination of nanomaterials modifiers with MIPs has endowed MIP-ECS with significantly improved sensing performance in the recent years, as the nanomaterial provide properties such as increased surface area, increased conductivity and electrocatalytic activity with enhanced electron transport phenomena, whereas MIPs provide selective recognition effect.
In the present review, we have summarised the advances of MIP-ECS electrochemical sensors reported in last six years (2017–2022) for sensing of variety of contaminates including drugs, metal ions, hormones and emerging contaminates. Scope of computational modelling in design of sensitive and selective MIP-ECS is reviewed. We have focused particularly on the synthetic protocols for MIPs preparation including bulk, precipitation, electropolymerization, sol-gel and magnetic MIPs. Moreover, use of various nanomaterial as modifiers and sensitizers and their effects on the sensing performance of resulting MIP-ECS is described. Finally, the potential challenges and future prospects in the research area of MIP-ECS have been discussed.
The world today lives in a state of terrible fear due to the mutation of the emerging COVID-19. With the continuation of this pandemic, there is an urgent need for fast, accurate testing devices to detect the emerging SARS-CoV-2 pandemic in terms of biosensors and point-of-care testing. Besides, the urgent development in personal defense tools, anti-viral surfaces and wearables, and smartphones open the door for simplifying the self-diagnosis process everywhere. This review introduces a quick COVID-19 overview: definition, transmission, pathophysiology, the identification and diagnosis, mutation and transformation, and the global situation. It also focuses on an overview of the rapidly advanced technologies based on nanomaterials and MOFs for biosensing, diagnosing, and viral control of the SARS-CoV-2 pandemic. Finally, highlight the latest technologies, applications, existing achievements, and preventive diagnostic strategies to control this epidemic and combat the emerging coronavirus. This humble effort aims to provide a helpful survey that can be used to develop a creative solution and to lay down the future vision of diagnosis against COVID-19.
Microbial activity and biomass are important factors that determine nutrient and carbon fluxes in freshwater ecosystems and, therefore are also related to both water quality and climate change induced stressors. This study aimed at assessing the feasibility of a power assisted Microbial Fuel Cell (MFC)-based biosensors for the continuous monitoring of microbial activity and biomass concentrations in saturated freshwater ecosystems. For this purpose, four lab-scale reactors were constructed and operated for 30 weeks. Reactors were fed with four different organic matter concentrations to promote a suite of microbial activity and biomass conditions. The reactors consisted of 3.8 L PVC vessels filled with 23 extractable gravel- sockets, used for microbial activity and biomass assessment, and 1 MFC granular-graphite socket, for biosensing assessment. Microbial activity was determined by the ATP content and the hydrolytic enzymatic activity, and the biomass content was assessed as the volatile solids attached to the gravel. Very significant linear relationships could be established between the parameters studied and the current density produced by the MFC with a very short detection time: 10 min for the ATP content (R² = 0.88) and 1 h for the enzymatic activity (R² = 0.78) and biomass (R² = 0.74). Moreover, the power assisted MFC-based biosensing tool demonstrated to be functional after a long operation time and under a wide range of organic loading conditions. Overall, the results highlight the feasibility to develop a power assisted MFC-based biosensor for on-line monitoring of the microbial activity and biomass of a given ecosystem (either natural or artificial) even in remote locations.
The application and fabrication of graphene-based nanomaterials have recently received great attention in the field of sensors. In this study, a graphene oxide (GO)-based heavy metals nanosensor was prepared via the surface reversible addition-fragmentation chain transfer (RAFT) method. To end this, GO was first prepared from graphene and followed by it was modified with L-phenylalanine (LP). Then, a RAFT agent was attached chemically to the LP-functionalized GO (GO-LP). Finally, GO-LP/polymethacrylamide (GO-LP/PMAM) was prepared via the polymerization of methacrylamide (MAM) monomers on the surface of the GO. The chemical structure and properties of the prepared materials were considered by FT-IR, SEM, TGA, UV, and PL techniques. The results of PL indicated that the GO-LP/PMAM has a higher PL intensity compared to GO and GO-LP spectra in the water. Ultimately, the modified GO was employed as an excellent nanosensor for the selective detection of Cu (II) ions in the range of 0.25–2 mM (R2 = 0.9903) with a limit of detection (LOD) of 0.19 mM. The absence of any obvious alteration in the fluorescence intensity after the addition of other metal ions indicated the great selectivity for the detection of Cu (II). Based on the experimental results, the surface functionalization of GO with RAFT strategy could be successfully employed as a promising nanosensor for selective detecting of Cu (II) ions.
This chapter outlines the contribution of luminescent techniques (fluorescence and phosphorescence) to monitor the quality of waters. An initial section summarizes the principles and features of luminescence, the determination of intrinsically fluorescent analytes vs. indicator-based sensors, the photochemical quenching of electronic excited states, the alternative mechanisms of luminescence-based sensing, and the technological advances that have enabled the modern luminescent sensors and biosensors for waterborne species. Then, with a critical approach, we review their current status, with particular emphasis on dissolved gases (CO2, O2, Cl2) and related species, ions (pH, cations, anions), organic pollutants (including hydrocarbons and waterborne organic matter), general toxicity, and pathogenic microorganisms. Selected cases help to illustrate the main features and operation principle of the different sensors, and the advantages that luminescent sensors, biosensors and biomimetic sensors provide over competing techniques.
This study, it is aimed to develop an electrochemical aptasensor that can detect phosphate ions using 3.3'5.5' tetramethylbenzidine (TMB). It is based on the principle of converting the binding affinity of the target molecule phosphate ion (PO43-) into an electrochemical signal with specific aptamer sequences for the aptasensor to be developed. The aptamer structure served as a gate for the TMB to be released and was used to trap the TMB molecule in mesoporous silica nanoparticles (MSNPs). The samples for this study were characterized by transmission electron spectroscopy (TEM), Brunner-Emmet-Teller, dynamic light scattering&electrophoretic light scattering, and induction coupled plasma atomic emission spectroscopy. According to TEM analysis, MSNPs have a morphologically hexagonal structure and an average size of 208 nm. In this study, palladium-carbon nanoparticles (Pd/C NPs) with catalytic reaction were used as an alternative to the biologically used horseradish peroxidase (HRP) enzyme for the release of TMB in the presence of phosphate ions. The limit of detection (LOD) was calculated as 0.983 μM, the limit of determination (LOQ) was calculated as 3.276 μM, and the dynamic linear phosphate range was found to be 50-1000 μM. The most important advantage of this bio-based aptasensor assembly is that it does not contain molecules such as a protein that cannot be stored for a long time at room temperature, so its shelf life is very long compared to similar systems developed with antibodies. The proposed sensor shows good recovery in phosphate ion detection and is considered to have great potential among electrochemical sensors.
A simple and highly sensitive single walled carbon nanotube (SWNT) sensor is provided for detection of a variety of analytes, including small molecules, macromolecules, and pathogens. The high sensitivity, specificity, stability, and rapid operation of the sensor render it useful for detection and quantification of low level contaminants such as pharmaceuticals and pathogens in environmental samples, including wastewater and natural bodies of water.
The food-borne diseases triggered by Escherichia coli O157: H7 (E. coli O157: H7) have become a life-threatening problem for tens of thousands of people around the world in the past few decades. Therefore, a rapid, simple, and user-friendly biosensing label to monitor E. coli O157: H7 has become necessary and important. In this work, carboxyl functionalized graphene quantum dots (cf-GQDs) as fluorescent labels for optical imaging and sensing in E. coli O157: H7 have been firstly proposed and evaluated. E. coli O157: H7 antibody is successfully covalently conjugated to water-soluble cf-GQDs via a cross-linking reaction, and then cf-GQDs immunofluorescence probe is achieved. The probe can effectively recognize E. coli O157: H7 and generate strong fluorescent signal. The experimental result shows that the blocking agent can obviously improve the specificity of the bioprobe for E. coli O157: H7 with the minimum detection limit of 100 cfu/mL. This novel detection method could be as a useful tool to detect E. coli O157: H7 in food, water, and environment.
Hexavalent chromium (Cr(VI)) is a well-known toxic heavy metal in industrial wastewater, but in situ and real time monitoring cannot be achieved by current methods used during industrial wastewater treatment processes. In this study, a Sediment Microbial Fuel Cell (SMFC) was used as a biosensor for in situ real-time monitoring of Cr(VI), which was the organic substrate is oxidized in the anode and Cr(VI) is reduced at the cathode simultaneously. The pH 6.4 and temperature 25 °C were optimal conditions for the operation. Under the optimal conditions, linearity (R² = 0.9935) of the generated voltage was observed in the Cr(VI) concentration range from 0.2 to 0.7 mg/L. The system showed high specificity for Cr(VI), as other co-existing ions such as Cu2+, Zn2+, and Pb2+did not interfere with Cr(VI) detection. In addition, when the sediment MFC-based biosensor was applied for measuring Cr(VI) in actual wastewater samples, a low deviation (<8%) was obtained, which indicated its potential as a reliable biosensor device. MiSeq sequencing results showed that electrochemically active bacteria (GeobacterandPseudomonas) were enriched at least two-fold on the biofilm of the anode in the biosensor as compared to the SMFC without Cr(VI). Cyclic voltammetry curves indicated that a pair of oxidation/reduction peaks appeared at -111 mV and 581 mV, respectively. These results demonstrated that the proposed sediment microbial fuel cell-based biosensor can be applied as an early warning device for real time in situ detection of Cr(VI) in industrial wastewaters.
Water pollution has become one of the leading causes of human health problems. Low molecular weight pollutants, even at trace concentrations in water sources, have aroused global attention due to their toxicity after long-time exposure. There is an increased demand for appropriate methods to detect these pollutants in aquatic systems. Aptamers, single-stranded DNA or RNA, have high affinity and specificity to each of their target molecule, similar to antigen-antibody interaction. Aptamers can be selected using a method called Systematic Evolution of Ligands by EXponential enrichment (SELEX). Recent years we have witnessed great progress in developing aptamer selection and aptamer-based sensors for low molecular weight pollutants in water sources, such as tap water, seawater, lake water, river water, as well as wastewater and its effluents. This review provides an overview of aptamer-based methods as a novel approach for detecting low molecular weight pollutants in water sources.
A self-supported nanoporous cobalt phosphide (CoP) nanowire arrays on the carbon cloth (CC) as an active matrix was fabricated and utilized as an interface for the construction of hemoglobin (Hb)-based biosensors. This matrix was wrapped in a thin aluminum sheet by handmade. Moreover, the electrochemistry and electrocatalytic properties of Hb were investigated on such a matrix. The results revealed that the self-supported nanoporous CoP nanowire arrays on CC significantly enhanced the electrochemical responses of Hb. In the meantime, the immobilized Hb remained its good bioactivity and high catalytic activity to hydrogen peroxide (H2O2). This matrix is thus a suitable platform to develop highly sensitive enzyme-based biosensor, which has the linear range of H2O2 concentration from 2 to 2670 μM with a detection limit of 0.7 μM (S/N = 3). Consequently, it is desirable to explore the possibility of developing a kind of simpler and cheaper matrix electrode.
The environmental monitoring has been one of the priorities at the European and global scale due to the close relationship between the environmental pollution and the human health/socioeconomic development. In this field, the biosensors have been widely employed as cost-effective, fast, in situ, and real-time analytical techniques. The need of portable, rapid, and smart biosensing devices explains the recent development of biosensors with new transduction materials, obtained from nanotechnology, and for multiplexed pollutant detection, involving multidisciplinary experts. This review article provides an update on recent progress in biosensors for the monitoring of air, water, and soil pollutants in real conditions such as pesticides, potentially toxic elements, and small organic molecules including toxins and endocrine disrupting chemicals.
The monitoring of toxicity of water is very important to estimate the safety of drinking water and the level of water pollution. Herein, a small microbial three-electrode cell (M3C) biosensor filled with polystyrene particles was proposed for on-line monitoring the acute water toxicity. The peak current of the biosensor related with the performance of bioanode was regarded as the toxicity indicator, and thus the acute water toxicity could be determined in terms of inhibition ratio through comparing the peak current obtained with water sample to that obtained with non-toxic standard water. The incorporation of polystyrene particles in the electrochemical cell not only reduced the volume of the samples used, but also improved the sensitivity of the biosensor. Experimental conditions including washing time with PBS and the concentration of sodium acetate solution were optimized. The stability of the M3C biosensor under optimal conditions was also investigated. The M3C biosensor was further examined by formaldehyde at the concentration of 0.01%, 0.03% and 0.05% (v/v), and the corresponding inhibition ratios were 14.6%, 21.6% and 36.4%, respectively. This work provides a new insight into the development of an on-line toxicity detector based on M3C biosensor.
An electrochemical organophosphorus hydrolase-based sensor for direct organophosphorus pesticides determination was developed, analytically characterized and applied for paraoxon quantification. The biosensing platform was constructed by one-step electrodeposition onto the surface of a glassy carbon electrode of a bionanocomposite of chitosan with carbon nanotube (CNTs), hydroxyapatite (HA) and organophosphorus hydrolase. The sensor, optimized with respect to the CNTs and HA load, was characterized by the application of cyclic voltammetry and chronoamperometry. The limit of detection (LOD) was found to be as low as 0.1 µmol L⁻¹, the linear concentration range was extended up to 80 µmol L⁻¹, and the sensitivity was as high as 5.10 nA L µmol⁻¹. The sensor possesses enhanced sensitivity towards organophosphorus pesticides (OPs), because of the CNTs and the HA nanoparticles synergistic action.
With the unprecedented deterioration of environmental quality, rapid recognition of toxic compounds is paramount for performing in situ real-time monitoring. Although several analytical techniques based on electrochemistry or biosensors have been developed for the detection of toxic compounds, most of them are time-consuming, inaccurate, or cumbersome for practical applications. More recently, microbial fuel cell (MFC)-based biosensors have drawn increasing interest due to their sustainability and cost-effectiveness, with applications ranging from the monitoring of anaerobic digestion process parameters (VFA) to water quality detection (e.g., COD, BOD). When a MFC runs under correct conditions, the voltage generated is correlated with the amount of a given substrate. Based on this linear relationship, several studies have demonstrated that MFC-based biosensors could detect heavy metals such as copper, chromium, or zinc, as well as organic compounds, including p-nitrophenol (PNP), formaldehyde and levofloxacin. Both bacterial consortia and single strains can be used to develop MFC-based biosensors. Biosensors with single strains show several advantages over systems integrating bacterial consortia, such as selectivity and stability. One of the limitations of such sensors is that the detection range usually exceeds the actual pollution level. Therefore, improving their sensitivity is the most important for widespread application. Nonetheless, MFC-based biosensors represent a promising approach towards single pollutant detection.
An economical single use optical biosensor has been developed for lead detection using a microfluidic approach. The present study represents the initiative step for amalgamation of microfluidic and advanced biosensor technologies which offers rapid analysis with lab-on-a-chip policy. Urease producing Bacillus sphaericus was co-immobilized with phenol red (pH indicator) in the glass capillary which acted as a microchannel. For immobilization, a combination of sol-gel approach and calcium alginate method cited first time in literature was used which reduced the time of solidification to seconds as compared to hours with sol-gel alone. Bioassay principle was based on urease inhibition in the presence of lead. Fiber optic spectrophotometer was used as transducer which measured the intensity of color change. Linear relationship (10-1000 µg/L) was observed between logarithmic concentration of lead and absorbance. The study resulted in the development of cheap, miniaturized, sensitive and reliable lead biosensor with requirement of small sample volume (1 mL). Differential Pulse Cathodic Stripping Voltametry (DPCSV) are superseded by the use of biosensors [10,11]. Biosensors are analytical tools capable of providing either qualitative or quantitative results, consisting of an immobilized biological recognition element such as an enzyme, antibody or cell receptor immobilized to a physicochemical transducer to create a single unit. Now-a-days biosensor technology has emerged as the most promising tool for detection of heavy metals being cost-effective, fast, selective, sensitive, portable, easy to use and reliable [12]. A number of lead biosensors have been developed using various transducers like conductometer [13-15], electrochemical [16-22] and optical [3,23-27] based on whole cell, enzymes or DNAzyme. The present study depicts the use of optical transducer along with microfluidic approach. Microfluidic system allows the controlled flow of operations like fluid transport, valving, mixing, separation, concentration and detection in Lab-on-a-Chip field [28] which helps to overcome the matrix effect, a major hindrance in the widespread use of biosensors for extra laboratory testing and drug arrays. Fluids are pumped into a particular channel known as microchannel at defined rate. Microfluidic is competent to analyze small sample volumes e.g. 10-9 – 10-18 L [29]. A few reports are available for use of microfluidic approach in biosensor technology. Chang and his workers [30] fabricated a microfluidic biosensor for lead detection using DNAzyme exhibiting linearity in the range of 0.1-100 µM (0.02-20.7 mg/L) concentration of lead with detection limit of 11 nM. The biosensor developed in this study demonstrated the linear range of 10-100 µg/L Pb 2+ which is far lower than previously described biosensor making it suitable for the application in milk, water and
Biosensors could be used as digital devices to measure the sample infield. Consequently, computational programming along with experimental achievements are required. In this study, a novel biosensor/artificial neural network (ANN) integrated system was developed. Poly (3,4-ethylenedioxy-thiophene)(PEDOT), graphene oxide nano-sheets (GONs) and laccase (Lac) were used to construct a biosensor. The simple and one-pot process was accomplished by electropolymerizing 3,4-ethylenedioxy-thiophene (EDOT) along with GONs and Lac as dopants on glassy carbon electrode. Scanning electron microscopy (SEM) and electrochemical characterization were conducted to confirm successful enzyme entrapment. The modified electrode was employed to detect and measure catechol. The reaction of catechol and the prepared electrode was controlled by adsorption. Linear responses of the biosensor were over two ranges, 0.036–0.35 μM and 0.35–2.5 μM, with a detection limit of 0.032 μM. The proposed biosensor was tested in real water samples successfully. The experimental test results were applied to train ANNs by the back-propagation algorithm. The input and output parameters were current and catechol concentration, respectively. Results from ANN modeling complied well with the experiments, signifying its useful application in biosensor technology.
The standard 5-days biochemical oxygen demand (BOD) method used for determination of
biologically oxidizable organic material in wastewater considered to be laborious, time consuming and
costly. Mediator-less microbial fuel cell (MFC) based biosensor offers an efficient alternative approach
for real time monitoring of biodegradable organic matter in wastewater. Here we constructed an Hshaped
MFC biosensor for comparing the efficiency of a complex natural (activated sludge) and
artificially designed bacterial (Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus
circulans) consortia as biological sensing elements for BOD measurements. Initially, the MFC
biosensor was optimized and calibrated at pH 7 and temperature 37oC using 100 mM phosphate buffer
with 100 mM NaCl solution as catholyte at 10 kΩ external resistance. Maximum power density of 14.2
mW/cm2
was generated by MFC-I with sludge consortium and it was 5 folds higher than MFC-II with
artificial consortium. Standard glucose and glutamic acid (GGA) solutions were used for establishing
the calibration curves between different BOD concentrations (50-250 mg/L) and voltage (mV) outputs
in MFC. The regression equations for MFC-I and MFC-II biosensors were recorded as y1 = 0.7834x-
11.638 and y2 = 0.1667x + 0.8476 respectively. Linear regression analysis revealed that 1 unit (mg/L)
increase in organic load caused a voltage increase of 0.78 mV and 0.16 mV in the MFCs (I and II)
reactors respectively. The relative performance in terms of stability (55-60 days) and reproducibility
(within ±15.4%) of MFC-I BOD biosensor was almost double than MFC-II. The varying low
concentrations of different electron acceptors (phosphate, nitrate and nitrite) in anodic compartments
did not affect the performance of MFC biosensors.
An electrochemical immunosensor for the common food pathogen Escherichia coli O157:H7 was developed. This novel immunosensor based on the PPy/AuNP/MWCNT/Chi hybrid bionanocomposite modified pencil graphite electrode (PGE). This hybrid bionanocomposite platform was modified with anti-E. coli O157:H7 monoclonal antibody. The prepared bionanocomposite platform and immunosensor was characterized by using cyclic voltammetry (CV). Under the optimum conditions, the results have shown the order of the preferential selectivity of the method is gram negative pathogenic species E. coli O157:H7. Concentrations of E. coli O157:H7 from 3 × 10¹ to 3 × 10⁷ cfu/mL could be detected. The detection limit was ∼30 cfu/mL in PBS buffer. Briefly, we developed a high sensitive electrochemical immunosensor for specific detection of E. coli O157:H7 contamination with the use of sandwich assay evaluated in this study offered a reliable means of quantification of the bacteria. For the applications in food quality and safety control, our immunosensor showed reproducibility and stability.
Water scarcity is a rapidly growing concern around the globe, but little is known about how it has developed over time. This study provides a first assessment of continuous sub-national trajectories of blue water consumption, renewable freshwater availability, and water scarcity for the entire 20 th century. Water scarcity is analysed using the fundamental concepts of shortage (impacts due to low availability per capita) and stress (impacts due to high consumption relative to availability) which indicate difficulties in satisfying the needs of a population and overuse of resources respectively. While water consumption increased fourfold within the study period, the population under water scarcity increased from 0.24 billion (14% of global population) in the 1900s to 3.8 billion (58%) in the 2000s. Nearly all sub-national trajectories show an increasing trend in water scarcity. The concept of scarcity trajectory archetypes and shapes is introduced to characterize the historical development of water scarcity and suggest measures for alleviating water scarcity and increasing sustainability. Linking the scarcity trajectories to other datasets may help further deepen understanding of how trajectories relate to historical and future drivers, and hence help tackle these evolving challenges.
Biochemical oxygen demand (BOD) is a widely used index of water-quality assessment. Since bioelectrochemical BOD biosensors require anaerobic conditions for anodic reactions, they are not directly used in aerobic environments such as aeration tanks. Normally, the BOD biosensors are closed-type, where the anode is packed inside a closed chamber to avoid exposure to oxygen. In this study, a novel bioelectrochemical open-type biosensor was designed for in-situ monitoring of BOD during intermittent aeration. The open-type anode, without any protection against exposure to oxygen, was directly inserted into an intermittently aerated tank filled with livestock wastewater. Anodic potential was controlled using a potentiostat. Interestingly, this novel biosensor generated similar levels of current under both aerating and non-aerating conditions, and showed a logarithmic correlation (R2 > 0.9) of current with BOD concentrations up to 250 mg/L. Suspended solids in the wastewater attached to and covered the whole anode, presumably leading to the production of anaerobic conditions inside the covered anode via biological oxygen removal. Exoelectrogenic anaerobes (Geobacter spp.) were detected inside the covered anode using the 16S-rRNA gene. This biosensor will have various practical applications, such as the automatic control of aeration intensity and the in-situ monitoring of natural water environments.
Various water samples were successfully evaluated using a panel of different recombinant bioluminescent bacteria and estrogenic activity analysis. The bioluminescent bacteria strains induced by oxidative (superoxide radical or hydroxyl radical), protein damage, cell membrane damage, or cellular toxicity were used. Estrogenic activities were examined by using the yeast strain BY4741, which carries the β-galactosidase reporter gene under the control of the estrogen-responsive element (ERE). A total of 14 samples from three wastewater treatment plants, one textile factory, and seawater locations in Tunisia were analyzed. A wide range of bio-responses were described. Site/sample heterogeneity was prevalent, in combination with generally high relative bioluminescence scores for oxidative stress (OH•). Estrogenic activity was detected at all sites and was particularly elevated at certain sites. Our perspectives include the future exploration of the variation detected in relation to treatment plant operations and environmental impacts. In conclusion, this new multi-experimental method can be used for rapid bio-response profile monitoring and the evaluation of environmental samples spanning a wide range of domains. This study confirms that bio-reactive wastewater treatment plant (WWTP) effluents are discharged into seawater, where they may impact coastal populations.
Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare.
In this research, an enzyme-free and label-free surface plasmon resonance (SPR) biosensing strategy has been developed for ultrasensitive detection of fusion gene based on the heterogeneous target-triggered DNA self-assembly aptamer-based hydrogel with streptavidin (SA) encapsulation. In the presence of target, the capture probes (Cp) immobilized on the chip surface can capture the PML/RARα, forming a Cp-PML/RARα duplex. After that, the aptamer-based network hydrogel nanostructure is formed on the gold surface via target-triggered self-assembly of X shaped polymers. Subsequently, the SA can be encapsulated into hydrogel by the specific binding of SA aptamer, forming the complex with super molecular weight. Thus, the developed strategy achieves dramatic enhancement of the SPR signal. Using PML/RARα "S" subtype as model analyte, the developed biosensing method can detect target down to 45.22 fM with a wide linear range from 100 fM to 10 nM. Moreover, the high efficiency biosensing method shows excellent practical ability to identify the clinical PCR products of PML/RARα. Thus, this proposed strategy presents a powerful platform for ultrasensitive detection of fusion gene and early diagnosis and monitoring of disease.
Two-dimensional (2D) MoS2 shows great potential in the areas of electrochemical sensors due to their ultrathin structure and predominant physicochemical properties. However, pristine 2D MoS2 nanostructure exists inherent disadvantages such as the limited electrical conductivity, surface area and easy aggregation or restacking. Here, nitrogen-fluorine co-doped monolayer 2D MoS2 nanosheet decorated with Ag nanoparticles (Ag NPs-N-F-MoS2) nanocomposite is prepared and it exhibits superior conductivity, remarkable electron mobility and high electroactive surface area. The obtained Ag NPs-N-F-MoS2 are employed as a sensing platform for the electrochemical determination of organophosphate pesticide, coupled with enzymatic inhibition. Under optimized conditions, the acetylcholinesterase (AChE)/amino functionalized carbon nanotubes (CNTs-NH2)/Ag NPs-N-F-MoS2 bioelectrode is superior in sensing performances for the detection of monocrotophos and chlorpyrifos, with wide linear ranges, low detection limit as low as 0.05 pg mL⁻¹ (0.2 pM) and 1 pg mL⁻¹ (3 pM) at a signal-to-noise ratio of 3, satisfactory selectivity, reproducibility and long-time storage stability. All results indicate that the Ag NPs-N-F-MoS2 nanocomposite holds great promise for constructing an ultra-sensitive electrochemical sensing interface for the determination of pesticides.
An excess of the excitatory neurotransmitter, glutamate, in the synaptic cleft during hypoxia/ischemia provokes development of neurotoxicity and originates from the reversal of Na⁺-dependent glutamate transporters located in the plasma membrane of presynaptic brain nerve terminals. Here, we have optimized an electrochemical glutamate biosensor using glutamate oxidase and developed a biosensor-based methodological approach for analysis of rates of tonic, exocytotic and transporter-mediated glutamate release from isolated rat brain nerve terminals (synaptosomes). Changes in the extracellular glutamate concentrations from 11.5 ± 0.9 to 11.7 ± 0.9 μΜ for 6 min reflected a low tonic release of endogenous glutamate from nerve terminals. Depolarization-induced exocytotic release of endogenous glutamate was equal to 7.5 ± 1.0 μΜ and transporter reversal was 8.0 ± 1.0 μΜ for 6 min. The biosensor data correlated well with the results obtained using radiolabelled L-[¹⁴C]glutamate, spectrofluorimetric glutamate dehydrogenase and amino acid analyzer assays. The blood plasma glutamate concentration was also tested, and reliability of the biosensor measurements was confirmed by glutamate dehydrogenase assay. Therefore, the biosensor-based approach for accurate monitoring rates of tonic, exocytotic and transporter-mediated release of glutamate in nerve terminals was developed and its adequacy was confirmed by independent analytical methods. The biosensor measurements provided precise data on changes in the concentrations of endogenous glutamate in nerve terminals in response to stimulation. We consider that the glutamate biosensor-based approach can be applied in clinics for neuromonitoring glutamate-related parameters in brain samples, liquids and blood plasma in stroke, brain trauma, therapeutic hypothermia treatment, etc., and also in laboratory work to record glutamate release and uptake kinetics in nerve terminals.
Parallel advances in chemical sensing and wireless communication technologies have sparked the development of wireless chemical sensors (WCSs). These hybrid devices enable wireless determination, collection and distribution of (bio)chemical analytical information in a way that is significantly impacting the Sensor Internet of Things with applications in healthcare, defence, sport, the environment, and agriculture. Challenges and examples for each of the major chemical sensor and major radio technologies related to different application areas are reviewed, including the latest trends emerging from wearable sensors. The review focuses on radio-based WCSs, and finds that ubiquitous wireless technologies such as Bluetooth, ZigBee, radio-frequency identification (RFID) and near-field communication (NFC) are helping make analytical (bio)chemical sensing appropriate and realistic for mass market adoption, in particular for two major classes of chemical sensor – electrochemical and optical. The review provides an in-depth analysis of academic WCS research publications over the ten year period 2007–2017.
According to the World Health Organisation, worldwide waterborne diseases are responsible for nearly two million human deaths annually. Rapid and at-site screen of pathogenic microorganisms in drinking water can help to markedly reduce this number. Here we report an innovative, simple and low-cost, paper-based probe for detection of bacteria in water, fabricated by screen printing carbon electrodes onto hydrophobic paper. Electrochemical characterization of the printed electrodes confirmed fast-electron transfer, with an estimated electroactive surface area of 0.25 cm². The electrode surface was functionalised with carboxyl groups, prior to covalent immobilization of the lectin Concanavalin A (Con A), used as the biorecognition element. The system was then tested as an impedimetric sensor for bacteria in water. A linear increase in the probe charge transfer resistance was observed for bacterial concentrations ranging from 10³ to 10⁶ CFU mL⁻¹, with an estimated lower detection limit of 1.9 × 10³ CFU mL⁻¹. Considering its remarkable simplicity, cost-effectiveness and biodegradability, the sensor here reported could be an attractive solution for portable testing kits that address the challenges of traditional time-consuming and expensive lab-based analyses.
Cuprous oxide (Cu2O) nanostructure has been synthesized using an electrochemical method with a two-electrode system. Cu foils were used as electrodes and NH2(OH) was utilized as the reducing agent. The effects of pH and applied voltages on the morphology of the product were investigated. The morphology and optical properties of Cu2O particles were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and diffuse reflectance spectra. The synthesized Cu2O nanostructures that formed in the vicinity of the anode at 2V and pH=11 showed high uniform distribution, small size, and good electrochemical sensing. These Cu2O nanoparticles were coated on an Indium tin oxide (ITO) substrate and applied to detect non-enzyme glucose as excellent biosensors. The non-enzyme glucose biosensors exhibited good performance with high response, good selectivity, wide linear detection range, and a low detection limit at 0.4 µM. Synthesized Cu2O nanostructures are potential materials for a non-enzyme glucose biosensor.
Food safety always remains a grand global challenge to human health, especially in developing countries. To solve food safety pertained problems, numerous strategies have been developed to detect biological and chemical contaminants in food. Among these approaches, nanomaterials-based biosensors provide opportunity to realize rapid, sensitive, efficient and portable detection, overcoming the restrictions and limitations of traditional methods such as complicated sample pretreatment, long detection time, and relying on expensive instruments and well-trained personnel. In this review article, we provide a cross-disciplinary perspective to review the progress of nanomaterials-based biosensors for the detection of food contaminants. The review article is organized by the category of food contaminants including pathogens/toxins, heavy metals, pesticides, veterinary drugs and illegal additives. In each category of food contaminant, the biosensing strategies are summarized including optical, colorimetric, fluorescent, electrochemical, and immune- biosensors; the relevant analytes, nanomaterials and biosensors are analyzed comprehensively. Future perspectives and challenges are also discussed briefly. We envision that our review could bridge the gap between the fields of food science and nanotechnology, providing implications for the scientists or engineers in both areas to collaborate and promote the development of nanomaterials-based biosensors for food safety detection.
