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Pimenta dioica Mediated Biosynthesis of Gold Nanoparticles and Evaluation of Its Potential for Theranostic Applications
Abstract
In recent years, gold nanoparticles have emerged as promising agents for plasmonic sensing, photoacoustic imaging, photothermal therapy, and other biomedical applications. In this work, green synthesis of plant‐mediated gold nanoparticles (AuNPs) using an aqueous leaf extract of Pimenta dioica was carried out and the synthesized nanoparticles were characterized using X‐ray diffraction (XRD), ultraviolet‐visible (UV‐Vis) absorption spectroscopy, Fourier transform infra‐red (FTIR) spectroscopy, and electron microscopy. A plausible mechanism of the formation of gold nanoparticles from Pimenta dioica leaf extract was also proposed. Synthesized AuNPs were found to be safe for human cervical cancer (HeLa) and human embryonic kidney 293 (HEK 293) cell lines established using MTT (3‐(4,5‐dimethylthiozol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide) assay. The potential of the synthesized nanoparticles for the plasmonic sensing of analyte molecule was carried out using the AuNPs as a surface‐enhanced Raman spectroscopy substrate. It was found that the AuNPs enhanced the Raman signal of analyte molecules with an enhancement factor of >10 ⁵ in comparison to the normal Raman signal measured from the analyte, i. e., without nanoparticles. Further, the synthesized AuNPs showed excellent photoacoustic signal responses (PASR) and found to be the most efficient photoacoustic signal generators. The photothermal performance of these nanoparticles was also carried out. Overall, the findings of this study suggest that in future, these AuNPs could be used as a green alternative to conventionally used in‐vivo theranostic agents.
... Consistent with literature reports [36], we observed that the average size of SP-AuNPs and SP-AgNPs was 5-30 nm and 10-40 nm, respectively. In a previous study, AuNPs obtained through a simple plant-mediated approach were highly monodispersed and spherical, with a size of 4 nm [37]. ...
... In addition, EDAX spectra exhibited strong absorption signals for Au (at 1.5 keV) and Ag (at 3 keV); the reported peaks for C. roseus extract-mediated AuNPs and AgNPs are similar to our observations. Consistent with literature reports [36], we observed that the average size of SP-AuNPs and SP-AgNPs was 5-30 nm and 10-40 nm, respectively. In a previous study, AuNPs obtained through a simple plant-mediated approach were highly monodispersed and spherical, with a size of 4 nm [37]. ...
Biological synthesis of metal nanoparticles has a significant impact in developing sustainable technologies for human, animal, and environmental safety. In this study, we synthesized gold and silver nanoparticles (NPs) using Sedeveria pink ruby (SP) extract and characterized them using UV–visible spectrophotometry, FESEM-EDX, HR-TEM, XRD, and FT-IR spectroscopy. Furthermore, antimicrobial and antioxidant activities and cytotoxicity of the synthesized NPs were evaluated. UV–visible absorption spectra showed λmax at 531 and 410 nm, corresponding to the presence of SP gold NPs (SP-AuNPs) and SP silver NPs (SP-AgNPs). Most NPs were spherical and a few were triangular rods, measuring 5–30 and 10–40 nm, respectively. EDX elemental composition analysis revealed that SP-AuNPs and SP-AgNPs accounted for >60% and 30% of NPs, respectively. Additionally, some organic moieties were present, likely derived from various metabolites in the natural plant extract, which acted as stabilizing and reducing agents. Next, the antimicrobial activity of the NPs against pathogenic microbes was tested. SP-AgNPs showed potent antibacterial activity against Escherichia coli and Yersinia pseudotuberculosis. Moreover, at moderate and low concentrations, both NPs exhibited weak cytotoxicity in chicken fibroblasts (DF-1) and macrophages (HD11) as well as human intestinal cancer cells (HT-29). Meanwhile, at high concentrations, the NPs exhibited strong cytotoxicity in both chicken and human cell lines. Therefore, the synthesized SP-AuNPs and SP-AgNPs may act as promising materials to treat poultry diseases.
... For example, ZnO NPs doped with Mn and Co showed higher toxicity compared to undoped ZnO NPs, and Fe-doped ZnO NPs had a similar effect [65]. However, Se-doped ZnO NPs exhibited decreased toxicity toward Escherichia coli in a study 178 M. Šebesta et al. ...
... Rizwan et al. [147,153] found that ZnO NPs positively affected the concentration of chlorophylls and, thus, the intensity of photosynthesis of wheat and maize. Schmidt et al. [177], Bellesi et al. [178], and Matzen et al. [179] state that a higher intensity of photosynthesis is a prerequisite for increasing the qualitative parameters of production, such as the content of starch, oil, dry matter, or crude protein. Higher intensity of photosynthesis is directly connected to lower water stress [180,181]. ...
Various industries, including agriculture, are increasingly interested in inorganic nanomaterials. Their smaller size (<100 nm) and tunability give rise to different chemical, physical, and biological properties compared with conventionally applied products. The study of the nanoworld with its unexplored processes and scientific challenges led to a new generation of more beneficial and efficient tools such as nanofertilizer and growth enhancers with either direct or gradual and well-regulated effects. The novelty of nanoparticles consists mainly in the reduction of inputs with the same function, for example, fertilizers in crop production, while also improving food quality, safety within the food chain, and the overall environmental impact. The aim of this chapter includes (1) effects of foliar application of engineered nanoparticles (mainly metallic) as new generation agrochemicals on plant production with (2) description of interactions in nanoparticle-plant systems, specifically their quantitative and qualitative nutritional parameters, (3) analysis of transfer and interaction of nanoparticles in leaves, and (4) palynological analysis in the context of impact on pollen quality to quantify distribution, transport, bioavailability, and potential toxicity of nanoparticles or their residues in field experimental setups.KeywordsFoliar applicationMetals and metal oxides nanoparticlesField studiesPlant productionQuantitative and nutritional parametersPhysiological responsePalynological analysisEnvironmental safety
... The occurrence of carboxylic acid, alkyl halides alkanes, and miscellaneous functional groups in P. dioica leaves have been reported by Murali et al. [27]. Kharey et al. [28] obtain green synthesized AuNPs using aqueous leaf extract of P. dioica. Using MTT (3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, synthesized AuNPs safe for human cervical cancer (HeLa) and human embryonic kidney 293 (HEK 293) cell lines. ...
... The peaks at 1340, 1210, and 1070 cm -1 correspond to the asymmetric and symmetric C-O-C stretching mode, respectively, which confirms the presence of the methoxy group on the benzene ring of eugenol [32]- [34]. These peaks are consistent with the FTIR peaks of functional groups of eugenol, present in the P. dioica plant [28]. ...
Green synthesis of gold nanoparticles (AuNPs) is of particular interest due to their catalytic, antioxidant, and antibacterial properties. In this study, the aqueous extract of Pimenta dioica leaves was used to synthesize AuNPs and the effective parameters were investigated. The prepared AuNPs were characterized by various techniques including UV–Vis absorption spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), and X-ray diffractometer (XRD). The reduction and stabilization effect of the plant extract to fabricate AuNPs were explained by FTIR analysis. TEM imaging confirmed the formation of spherical-shaped AuNPs. The catalytic activity of synthesized nanoparticles was evaluated in the degradation of a Methylene Blue dye in the presence of NaBH4 as reducing agent and achieved after only two minutes. The AuNPs provided high antioxidant ability. In addition, the synthesized AuNPs showed a significant inhibitory effect against both gram-positive and gram-negative bacteria, where the zone of inhibition of 4 and 9 mm were obtained for synthesized AuNPs against S. aureus and E. coli, respectively.
In the present study, carbon quantum dots (CDQs) modified coumarine-3-carboxylic acid (CCA) and 7-diethyl amino coumarine-3-carboxylate (DACC) were synthesized by microwave assisted method and the synthesized hybrid nanomaterials possess greater biocompatibility, water solubility, luminescent and fluorescent properties. The hybrid CDQs: CCA/DACC nanomaterials exhibit superior fluorescent properties and greater quantum yield when subjected for excitation. Also, they possess superior bio-imaging properties, fluorescent quenching and contribute for the modern diagnosis and cell identification techniques. When tested for cytotoxicity, the hybrid nanomaterial does not showed cytotoxicity against L929 mouse fibroblast. The results clearly indicated that, the hybrid nanomaterials with surface modified CQDs dispersed over CCA/DACC may become a powerful tool in the field of nano medicine and pharmacy
Nanotechnology is the management of substances on a scale of 1–100 nm. Nanotechnology-focused approaches have encouraged researchers to manufacture several drug delivery, bioimaging and biosensing platforms. It has similarly made it feasible to build a nanoparticle-based drug delivery system used for various drugs. The environment and public health are at risk due to the typical chemical synthesis methods utilized to create the nanomaterials. Here in we have focused on nanomaterials and their green manufacturing using plant-based leaf extracts that have emerged as a key area in biomedical research. Green chemistry-based synthesized nanomaterial due to its low cost, minimal danger to people and the environment are utilized widely in health care and medicine as well as drug development. Moreover, practices of plant-based extract are an inexpensive, biocompatible and easy to scale-up method for the design and development of metal nanoparticles from their respective precursors. In this current book chapter, we review the current progresses of green chemistry facilitated synthesis of nanoparticles and their biomedical functions including cancer theranostics, antibacterial, antifungal, biosensing etc.KeywordsNanomaterialsPlant-leaf based compoundsGreen chemistryMetallic nanoparticlesPhytoconstituents
Nature offers numerous resources for development of novel biomaterials which could be used for diverse range of applications. Nanobioconjugates (NBCs) are hybrid entities fabricated by coupling biomolecules along with nanomaterials, thereby establishing an interface between biology and chemistry. Green synthesis of NBCs involves usage of plant extracts and microbes adhering to the principles of green chemistry. The use of conventional physical and chemical methods for synthesizing nanoparticles (NPs) always results in potential hazards including toxicity, carcinogenicity and environmental damage. Several studies have been reported for the synthesis of nanomaterials using different plant extracts and micro-organisms that are used in association with biomolecules for various applications including bioimaging, diagnostics, drug delivery, biomedical and agricultural applications. In recent years, green synthesis of NPs has received a great deal of attention among the research community. NBCs can be produced during the biogenic synthesis of NPs, using plant extracts and/or microorganisms. The biomolecules present in the reaction system get adsorbed on the surface of the NPs as capping agents and stabilize the biogenically fabricated NPs. The NPs-biomolecule conjugate so produced can then be used for performing specific tasks. This chapter emphasizes on the need for green synthesis of nanomaterials, science behind the synthesis, their ability to conjugate with biomolecules producing NBCs, surface functionalization and the applications of NBCs in detail.
Nanoparticles and Plant–Microbe Interactions: An Environmental Perspective,
a volume in the Nanomaterial–Plant Interactions series, provides comprehensive coverage on how nanoparticles can impact plant–microbe interactions. Key themes include ethics of nanotechnology, nanoparticle synthesis, nanofarming, the negative impacts of nanoparticles, and nanomaterials in mitigating stress.
An Environmental Perspective
Nanotechnology is an emerging field with a vast range of nano-based products for commercial exploitation. The interactions of nanoparticles, plants, and microbes can be harnessed in several applications, including alleviating environmental pollution. However, there are also concerns surrounding the toxicity of nanoparticles themselves, and it is important to be aware of the potential negative effects.
Presented in four sections, beginning with core foundational information on the topic, the book then looks at nanotechnology with focus on the interaction between microbes and plants. The third section addresses the role of nanomaterials in mitigating stress, pollution, and climate change. The fourth section addresses the important consideration of potential negative impacts of nanoparticles on plants and the environment.
This book will be an essential read for any scientist or researcher looking to assess and understand the benefits and potential risks associated with plant nanotechnology, with particular focus on plant–microbe interactions.
The field of nanotechnology has attained significant attention over the years because of the diverse applications associated with the field in sectors including medicine, agriculture, environmental remediation and so on. Conventional synthetic procedures are associated with environmental hazards, and therefore focus has been shifted to evolving synthesis procedures that are not only cost-effective and environmental-friendly. To serve the purpose, biogenic synthesis of nanoparticles (NPs) has materialized as an environmentally benign practice. Secondary metabolites like terpenoids, flavonoids, and polyphenols found in plants act as reducing agents and aid in the reduction of metal ions to metal-based NPs. The chapter presents an overview of some of the recently reported metal and metal oxide-based NPs derived from plant sources, their characterization by techniques like Fourier transform infrared spectroscopy, UV-visible spectroscopy, transmission electron microscopy, etc. and the effect of different factors like temperature, pH and incubation period on the overall yield of the NPs. The chapter also elucidates the applications of biogenic NPs in different disciplines of science and technology.
Medicinal or herbal spices are grown in tropical moist evergreen forestland, surrounding most of the tropical and subtropical regions of Eastern Himalayas in India (Sikkim, Darjeeling regions), Bhutan, Nepal, Pakistan, Iran, Afghanistan, a few Central Asian countries, Middle East, USA, Europe, South East Asia, Japan, Malaysia, and Indonesia. According to the cultivation region surrounded, economic value, and vogue, these spices can be classified into major, minor, and colored tropical spices. In total, 24 tropical spices and herbs (cardamom, black jeera, fennel, poppy, coriander, fenugreek, bay leaves, clove, chili, cassia bark, black pepper, nutmeg, black mustard, turmeric, saffron, star anise, onion, dill, asafoetida, celery, allspice, kokum, greater galangal, and sweet flag) are described in this review. These spices show many pharmacological activities like anti-inflammatory, antimicrobial, anti-diabetic, anti-obesity, cardiovascular, gastrointestinal, central nervous system, and antioxidant activities. Numerous bioactive compounds are present in these selected spices, such as 1,8-cineole, monoterpene hydrocarbons, γ-terpinene, cuminaldehyde, trans-anethole, fenchone, estragole, benzylisoquinoline alkaloids, eugenol, cinnamaldehyde, piperine, linalool, malabaricone C, safrole, myristicin, elemicin, sinigrin, curcumin, bidemethoxycurcumin, dimethoxycurcumin, crocin, picrocrocin, quercetin, quercetin 4’-O-β-glucoside, apiol, carvone, limonene, α-phellandrene, galactomannan, rosmarinic acid, limonene, capsaicinoids, eugenol, garcinol, and α-asarone. Other than that, various spices are used to synthesize different types of metal-based and polymer-based nanoparticles like zinc oxide, gold, silver, selenium, silica, and chitosan nanoparticles which provide beneficial health effects such as antioxidant, anti-carcinogenic, anti-diabetic, enzyme retardation effect, and antimicrobial activity. The nanoparticles can also be used in environmental pollution management like dye decolorization and in chemical industries to enhance the rate of reaction by the use of catalytic activity of the nanoparticles. The nutritional value, phytochemical properties, health advantages, and both traditional and modern applications of these spices, along with their functions in food fortification, have been thoroughly discussed in this review
Magnetic nanocomposites are extensively used for biomedical applications such as drug delivery, diagnosis, and therapeutics, etc. Here we report a green synthesis of biocompatible, superparamagnetic, and near-infrared absorbing, iron oxide-gold composite nanoparticles (IO–Au NPs) using aqueous leaf extract of a medicinal plant Pimenta dioica for biomedical applications. The MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to assess the cytotoxicity of the IO-Au NPs in-vitro. Results of the MTT assay show that the green synthesized IO-Au NPs are safe for cells up to a high concentration of 500 μg/ml. The IO-AuNPs exhibit a superparamagnetic behavior with a large magnetization of 65 emu/g. These IO-Au NPs exhibit a high relaxivities ratio (r2/r1) of 13.20 (r1 = 10.67 s⁻¹ mM⁻¹ and r2 = 140.87 s⁻¹ mM⁻¹ respectively), indicating the potential of these IO-Au NPs as a T2 contrast agent. Magnetic resonance imaging of chicken tissue and poultry heart has been done to confirm the contrast enhancement performance of these nanoparticles. Moreover, the magnetic heating efficacy of the green synthesized IO-Au NPs has been evaluated in an external magnetic field. Owing to their excellent optical property, these green synthesized IO-Au NPs have great potential for NIR photothermal applications. The results of this study suggest that these IO-Au NPs could be used as theranostic agents for in-vivo biomedical imaging and therapeutics.
Allspice (Pimenta dioica L.) has been used since time immemorial for its culinary and medicinal qualities. Its unique characteristics are flavor conglomerates of cloves, nutmeg and cinnamon. Eugenol (60–90% in the berries, >90% in the leaves) is the key component followed by 1,8-cineole, α-humulene, β-caryophyllene and cadinene derivatives of pimenta essential oil that imparts health and wellness. Recent studies represent eugenol and gallic acid as selective antitumor and anti-proliferative agents besides excellent antioxidants, anticancerous agents, antimicrobial molecules. Currently, pimenta has received considerable attention in developed countries due to its promising pharmaceutical properties and culinary consumption. Thus, the need with emphasis for explorations of active packaging using the biomolecule from pimenta in developing flavor biofilms, micro and nano delivery systems in extending biomedical applications, food and beverage industries is indicated. This review emphasizes the processing, chemistry, applications of pimenta and impending modes of green and sustainable technologies besides the development of value-added products.
In the present situation, it is critical to meet the nutritional needs of the world’s rising population. Nearly one-third of crops are affected in conventional farming due to pathogens infestation. Nanotechnology can change agricultural production and improve plant growth by facilitating the cost-effective management of natural resources and other necessary inputs. Nanomaterials (NMs) in agriculture offer a once-in-a-lifetime opportunity to improve crop yield and preserve soil health. Potential NMs uptake in soil-plant systems and positive and negative effects in various crops have been observed in several studies. Because of their unique properties, NMs have received much attention in agriculture. NMs and nanotechnology improve the stability and dispersion of active ingredients, reduce residual pollution and labor costs, and maintain agricultural systems’ sustainability. Many nanomaterials-based formulations have been extensively used for plant growth and development, including nano-based associated pesticides and fertilizers in the modern agricultural system. Understanding the interactions between plants and NMs opens up new paths for improving agricultural crop yield and quality. This chapter helps readers better understand the role of NMs in plant growth and development.
The molecularly imprinted polymers (MIPs) technology, which has been around since the 1970s, has grown in popularity in recent decades. MIPs have shown to be a useful approach for determining target molecules in complicated matrices containing other structurally similar and related chemicals. Despite MIPs have intrinsic polymer features such as stability, robustness, and low-cost production, traditional MIPs have a number of drawbacks. Surface molecular imprinting appears to be an alternative approach that can address some of the drawbacks of traditional MIP by anchoring shells to the surface of matrix carriers such as nanoparticles. The incorporation of nanoparticles into the polymeric structure of MIPs can improve their properties or provide novel capabilities. Magnetic nanoparticles have been widely explored for their separation and extraction capability. Magnetic components in MIP can help develop a regulated rebinding process, allowing magnetic separation to substitute centrifugation and filtration stages in a simple and cost-effective strategy. Polymers are created directly on the surface of a magnetic substrate to create a unique material termed magnetic molecularly imprinted polymer (MMIP). These materials have been widely used to extract molecules from complex matrices in a variety of applications, especially in environmental, food, and biological studies. This paper seeks to summarize and discuss the nanoparticle synthesis and magnetic nanoparticle combination in the MIP preparation. The novel applications of MMIP in environmental, food, and biological analysis are also discussed in this paper.
Plants are anatomically and physiologically different from humans and animals; however, there are several possibilities to utilize the unique structures and physiological systems of plants and adapt them to new emerging technologies through a strategic biomimetic approach. Moreover, plants provide safe and sustainable results that can potentially solve the problem of mass-producing practical materials with hazardous and toxic side effects, particularly in the biomedical field, which requires high biocompatibility. In this review, it is investigated how micro–nanostructures available in plants (e.g., nanoparticles, nanofibers and their composites, nanoporous materials, and natural micromotors) are adapted and utilized in the design of suitable materials for a micro–nanorobot platform. How plants’ work on micro- and nanoscale systems (e.g., surface roughness, osmotically induced movements such as nastic and tropic, and energy conversion and harvesting) that are unique to plants, can provide functionality on the platform and become further prospective resources are examined. Furthermore, implementation across organisms and fields, which is promising for future practical applications of the plant-actuated micro–nanorobot platform, especially on biomedical applications, is discussed. Finally, the challenges following its implementation in the micro–nanorobot platform are also presented to provide advanced adaptation in the future.
Green synthesis of nanoparticles is an emerging topic with many significant applications in environmental and biomedical fields. The main aim of green synthesis is the development of eco-friendly nanoparticles using biological materials like plants and microbes and thus, reducing the practice of utilizing toxic substances. Different plant-derived materials are regularly utilized to synthesise sustainable nanoparticles with almost comparable properties yet utilize less hazardous manufacturing processes. This review aims to update these green synthetic processes for developing nanoparticles.
Nanotechnology has attracted the attention of researchers from different scientific fields because of the escalated properties of nanomaterials compared with the properties of macromolecules. Nanomaterials can be prepared through different approaches involving physical and chemical methods. The development of nanomaterials through plant‐based green chemistry approaches is more advantageous than other methods from the perspectives of environmental safety, animal, and human health. The biomolecules and metabolites of plants act as reducing and capping agents for the synthesis of metallic green nanomaterials. Plant‐based synthesis is a preferred approach as it is not only cost‐effective, easy, safe, clean, and eco‐friendly but also provides pure nanomaterials in high yield. Since nanomaterials have antimicrobial and antioxidant potential, green nanomaterials synthesized from plants can be used for a variety of biomedical and environmental remediation applications. Past studies have focused mainly on the overall biogenic synthesis of individual or combinations of metallic nanomaterials and their oxides from different biological sources, including microorganisms and biomolecules. Moreover, from the viewpoint of biomedical applications, the literature is mainly focusing on synthetic nanomaterials. Herein, we discuss the extraction of green molecules and recent developments in the synthesis of different plant‐based metallic nanomaterials, including silver, gold, platinum, palladium, copper, zinc, iron, and carbon. Apart from the biomedical applications of metallic nanomaterials, including antimicrobial, anticancer, diagnostic, drug delivery, tissue engineering, and regenerative medicine applications, their environmental remediation potential is also discussed. Furthermore, safety concerns and safety regulations pertaining to green nanomaterials are also discussed. This article is protected by copyright. All rights reserved.
Cancer is one of the most fatal diseases causing deaths of millions of people worldwide. Since actual cancer treatments are rarely efficient and often toxic, there is a demand for innocuous and more effective anticancer drugs. For instance, metal/metal oxide nanoparticles allow controlled drug release and drug delivery to specific targets. In particular, medicinal plant-based metal nanoparticles appear as safer and more effective. Here, we present the synthesis of metal nanoparticles using medicinal plant extracts, and the toxicity of these nanoparticles for cancerous cells. The anticancer effect is explained by several possible mechanisms such as generation of reactive oxygen species, cell cycle arrest, antioxidant property, apoptosis and autophagy. We present plant compounds that induce cytotoxicity against cancerous cells, and assays for the measurement of cell toxicity.
The genotypic diversity of 17 cacti species were examined and grouped in four clusters using seven inter
simple sequence repeat (ISSR) markers. Group representatives (five species) were chosen for AuNPs synthesis
in the cacti syrups. To synthesize the Gold nanoparticles (AuNPs), reducing and capping potential
of five species of cacti rich in the polyphenolics were explored. Based on the synthesized AuNPs traits
(concentration, pH, temperature, and synthesis time), Opuntia pycnacantha with the highest absorption
peak at 540 nm was chosen for further characterizations. Varieties of diffraction peaks confirmed the successful
synthesis of AuNPs. AuNPs functionalization with the phenolic compounds was confirmed by
Fourier transform infrared (FTIR) spectroscopy. At the optimum conditions (pH = 5.0 and T = 60 �C), both
dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed more than 87% of
AuNPs to be 2.5 nm in size with Zeta potential to be equal to �19.9 mV.
Green synthesis of nanoparticles has many potential applications in environmental and biomedical fields. Green synthesis aims in particular at decreasing the usage of toxic chemicals. For instance, the use of biological materials such as plants is usually safe. Plants also contain reducing and capping agents. Here we present the principles of green chemistry, and we review plant-mediated synthesis of nanoparticles and their recent applications. Nanoparticles include gold, silver, copper, palladium, platinum, zinc oxide, and titanium dioxide.
Highly efficient non‐noble metal electrocatalysts are vital for metal–air batteries and fuel cells. Herein, a noble‐metal–free single‐atom Fe‐N x‐C electrocatalyst is synthesized by incorporating Fe‐Phen complexes into the nanocages in situ during the growth of ZIF‐8, followed by pyrolysis at 900 °C under inert atmosphere. Fe‐Phen species provide both Fe²⁺ and the organic ligand (Phen) simultaneously, which play significant roles in preparing single‐atom catalysts. The obtained Fe‐Nx‐C exhibits a half‐wave potential of 0.91 V for the oxygen reduction reaction, higher than that of commercial Pt/C (0.82 V). As a cathode catalyst for primary zinc–air batteries (ZABs), the battery shows excellent electrochemical performances in terms of the high open‐circuit voltage (OCV) of 1.51 V and a high power density of 96.4 mW cm⁻². The rechargeable ZAB with Fe‐Nx‐C catalyst and the alkaline electrolyte shows a remarkable cycling performance for 300 h with an initial round‐trip efficiency of 59.6%. Furthermore, the rechargeable all‐solid‐state ZABs with the Fe‐Nx‐C catalyst show high OCV of 1.49 V, long cycle life for 120 h, and foldability. The single‐atom Fe‐Nx‐C electrocatalyst may function as a promising catalyst for various metal–air batteries and fuel cells.
Morphology, dimension, size, and surface chemistry of gold nanoparticles are critically important in determining their optical, catalytic, and photothermal properties. Although many techniques have been developed to synthesize various gold nanostructures, complicated and multistep procedures are required to generate three-dimensional, dendritic gold nanostructures. Here, we present a simple method to synthesize highly branched gold nanodendrites through the well-controlled reduction of gold ions complexed with a catechol-grafted polymer. Dextran grafted with catechols guides the morphological evolution as a polymeric ligand to generate dendritic gold structures through the interconnection of the spherical gold nanoparticles. The reduction kinetics, which is critical for morphological changes, is controllable using dimethylacetamide, which can decrease the metal–ligand dissociation and gold ion diffusivity. This study suggests that mussel-inspired polymer chemistry provides a simple one-pot synthetic route to colloidal gold nanodendrites that are potentially applicable to biosensing and catalysis.
Nanotechnology has become more and more potentially used in diagnosis or treatment of diseases. Advances in nanotechnology have led to new and improved nanomaterials in biomedical applications. Common nanomaterials applicable in biomedical applications include liposomes, polymeric micelles, graphene, carbon nanotubes, quantum dots, ferroferric oxide nanoparticles, gold nanoparticles (Au NPs), and so on. Among them, Au NPs have been considered as the most interesting nanomaterial because of its unique optical, electronic, sensing and biochemical properties. Au NPs have been potentially applied for medical imaging, drug delivery, and tumor therapy in the early detection, diagnosis, and treatment of diseases. This review focuses on some recent advances in the use of Au NPs as drug carriers for the intracellular delivery of therapeutics and as molecular nanoprobes for the detection and monitoring of target molecules.
Here we report a novel assembly structure of near-infrared plasmonic gold nanoparticles (AuNPs), possessing both photoacoustic (PA) and photothermal (PT) properties. The template for the plasmonic AuNP assembly is a bioconjugate between short double-strand DNA (sh-dsDNA) and human methyl binding domain protein 1 (MBD1). MBD1 binds to methylated cytosine-guanine dinucleotides (mCGs) within the sequence of sh-dsDNA. Hexahistidine peptides on the engineered MBD1 function as a nucleation site for AuNP synthesis, allowing the construction of hybrid conjugates, sh-dsDNA-MBD1-AuNPs (named DMAs). By varying the length of sh-dsDNA backbone and the spacer between two adjacent mCGs, we synthesized three different DMAs (DMA_5mCG, DMA_9mCG, and DMA_21mCG), among which DMA_21mCG exhibited a comparable photothermal and surprisingly a higher photoacoustic signals, compared to a plasmonic gold nanorod. Further, epidermal growth factor receptor I (EGFR)-binding peptides are genetically attached to the MBD1 of DMA_21mCG, enabling its efficient endocytosis into EGFR-overexpressing cancer cells. Notably, the denaturation of MBD1 disassembled the DMA and accordingly released the individual small AuNPs (<5 nm) that can be easily cleared from the body through renal excretion without causing accumulation/toxicity problems. This DMA-based novel approach offers a promising platform for targeted cancer theragnosis based on simultaneous PA imaging and PT therapy.
Due to increasing resistance of microorganisms towards current antibiotics, there is a need for new or enhanced antibiotics. Nanotechnology is a technology that enhances the use of gold nanoparticles (AuNP) in area of medical applications, especially as a drug carrier for targeted drug delivery. In this research, AuNPs was synthesized using biological method via bioreduction of Piper guineense aqueous leaf extract on tetra gold chloride, characterized using UV–Vis spectrophometer, DLS, TEM/EDS and FTIR. The synthesized AuNPs was covalently functionalized with polyethylene glycol and encapsulated with Lincomycin and in vitro dissolution methods was used to evaluate the potential performance of the formulated nanodrug. The nanodrug has highest release efficiency at the 9th minutes (23.4 mg ml⁻¹ for 40 °C) and (29.5 mg ml⁻¹ for 60 °C) compared with the non-nanodrug. The antibacterial potential of the nanodrug was seen on the gram-positive bacteria of Staphylococcus aureus and Streptococcus pyogenes with highest inhibitions of 18 mm (at 40 °C) and 16 mm (at 60 °C) for S. aureus, and 16 mm for S. pyogenes (both at 40 °C and 60 °C). The bacteria growth inhibition continued and lasted for 15 min, while that of non-nanodrug lasted for 9 min with lesser growth inhibition compared to the formulated nanodrug. This work shows that the presence of the AuNPs increased the release efficiency of lincomycin even at a lower concentration and also bacteria growth inhibition thereby suggesting the effectiveness of the nanodrug formulation.
The prominent challenges in manufacturing carrier systems for chemical, biological and medical applications are to produce stable, nontoxic and uniform dimension particles by using various macromolecules. In this respect, the emerging field of nanotechnology enables various approaches towards optimising synthesis protocols and methodologies. Depending on the application of the particles, various methodologies for nanoparticle synthesis have been adopted. Especially, gold nanoparticles (AuNPs) have tremendous potential for bionanotechnology-based applications, thus resulting in new possibilities and insights within the medical research field. These nanoparticles can be used for selective transportation mechanism through receptor ligand binding. During various synthesis processes of AuNps, several difficulties have been encountered. Therefore, the scientific research community turned its attention towards tuning and perfecting the obtaining approaches involved in AuNPs synthesis. This review aims to facilitate the understanding of different strategies used for AuNPs synthesis, as well as highlighting the challenges and future perspectives of AuNPs in bionanotechnology.
This study reports the biological synthesis of gold nanoparticles (AuNPs) by the reduction of HAuCl4 by using of Eclipta prostrata leaf extract as the reducing and stabilizing agent. AuNPs were characterized using Ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), Fourier Transform-Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), High Resolution-Transmission Electron Microscopy (HRTEM), and Energy Dispersive X-ray analysis (EDAX). The UV-visible spectrum of the synthesized AuNPs showed surface plasmon resonance (SPR) around 534 nm. The face-centered cubic (FCC) structure of the AuNPs was confirmed by XRD peaks at 38.10°, 44.13°, 64.43°, and 77.32°, which correspond to (111), (200), (220), and (311) miller indices, respectively, with clear circular spots in the selected area electron diffraction (SAED). FTIR measurements showed the AuNPs having a coating of phenolic compounds, indicating a possible role of biomolecules responsible for capping and efficient stabilization of the AuNPs. The HRTEM images determined the particles are spherical, hexagonal, and triangular in shape, with an average size of 31 ± 1.6 nm. The synthesized AuNPs show good antibacterial, antioxidant, and cytotoxic activity. The outcomes of this study indicate that these nanoparticles could be effectively utilized in pharmaceutical, biotechnological, and biomedical applications.
'Smart' gold nanoparticles can respond to mild acidic environments, rapidly form aggregates, and shift the absorption to red and near-infrared. They were used as a photoacoustic imaging agent responsive to the cancer microenvironment, and have demonstrated the cancer-specific accumulation at the cellular level and an amplified signal which is twice higher than the control in vivo.
Metallic nanoparticles are being utilized in every phase of science along with engineering
including medical fields and is still charming scientists to explore new dimensions for their
respective worth which is generally attributed to their corresponding small sizes. The up-andcoming
researches have proven their antimicrobial significance. Among several noble metal
nanoparticles, silver nanoparticles have attained a special focus. Conventionally silver
nanoparticles are synthesized by chemical method using chemicals as reducing agents which
later on become accountable for various biological risks due to their general toxicity;
engendering the serious concern to develop environment friendly processes. Thus, to solve
the objective; biological approaches are coming up to fill the void; for instance green
syntheses using biological molecules derived from plant sources in the form of extracts
exhibiting superiority over chemical and/ or biological methods. These plant based biological
molecules undergo highly controlled assembly for making them suitable for the metal
nanoparticle syntheses. The present review explores the huge plant diversity to be utilized
towards rapid and single step protocol preparatory method with green principles over the
conventional ones and describe the antimicrobial activities of silver nanoparticles.
Pimenta dioica(Linn.)Merill. (Myrtaceae) is well-renowned, industrially important, aromatic spice plant widely used in traditional systems of medicine, food, perfumery and cosmetic industries. Present study describes the essential oil content, composition, and antioxidant capacity of mature and immature leaves of Pimenta dioica. Essential oil was extracted using Clevenger-type apparatus for 5 hrs. Leaf essential oil composition was analyzed using GC-MS. Quantification of Total Antioxidant Capacity (TAC), Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) were carried out using standard methodologies. The oil yield was 0.80 % (v/w) of fresh weight. Twelve compounds comprising more than 97% of total composition were identified by GC/MS analysis. Eugenol (85.33±2.0 %) was identified as a major constituent of essential oil and followed by β-caryophylene (4.36±0.3%), cineole (4.19±0.3%),linalool (0.83±0.11%) and α-humulene (0.76±0.12%).Immature leaf extracts exhibited the marked Total Antioxidant Capacity (TAC) (537.18±11.62mg trolox equivalent per g of sample); Total Phenolic Content (TPC) (99.09±3.65 mg Gallicacid equivalent per g of sample), and Total Flavonoid Content (TFC) (136.71±3.24 mg Rutin equivalent per g of sample). Presence of greater amount of eugenol in essential oil, TAC, TPC and TFC in leaf extracts undoubtedly demonstrated potential of Pimenta dioica essential oil and leaf material as a fabulous raw material for food, perfumery and cosmetic industries. Further harvesting of immature leaves could be suggested for better therapeutic benefits.
Photoacoustic imaging (PAI) and thermoacoustic imaging (TAI) are two emerging biomedical imaging techniques that both utilize ultrasonic signals as an information carrier. Unique advantages of PAI and TAI are their abilities to provide high resolution functional information such as hemoglobin and blood oxygenation and tissue dielectric properties relevant to physiology and pathology. These two methods, however, may have a limited detection depth and lack of endogenous contrast. An exogenous contrast agent is often needed to effectively resolve these problems. Such agents are able to greatly enhance the imaging contrast and potentially break through the imaging depth limit. Furthermore, a receptor-targeted contrast agent could trace the molecular and cellular biological processes in tissues. Thus, photoacoustic and thermoacoustic molecular imaging can be outstanding tools for early diagnosis, precise lesion localization, and molecular typing of various diseases. The agents also could be used for therapy in conjugation with drugs or in photothermal therapy, where it functions as an enhancer for the integration of diagnosis and therapy. In this article, we present a detailed review about various exogenous contrast agents for photoacoustic and thermoacoustic molecular imaging. In addition, challenges and future directions of photoacoustic and thermoacoustic molecular imaging in the field of translational medicine are also discussed.
Pimenta dioica (Linn.) Merill. Family: Myrtaceae, well known for its berries called Pimento, has been used as an important spice since time immemorial, for its culinary as well as medicinal qualities. It is also known as Allspice due to its intricate aroma which is a medley of aroma from spices such as Clove, Nutmeg and Cinnamon. In India, the leaves of Pimenta are used to flavor rice which gives it a typical aroma. Traditional culinary practice uses the dried berries for marinating meat. Various compounds have been isolated from the plant which belong to categories like phenylpropanoids, tannins, glycosides and essential oil. The present article is a humble effort to study the work done till date on this important spice. DOI: http://dx.doi.org/10.3329/icpj.v1i8.11255 International Current Pharmaceutical Journal 2012, 1(8): 221-225
Abstract
Background: Eugenol is a potent phytochemical, and a plethora of delivery systems for this bioactive agent is being developed. Reversed-phase high-pressure liquid chromatography equipped with photodiode array detector (RP-HPLC-PDA) method is very useful in the quantification of the phytochemicals.
Methods: The RP-HPLC-PDA system with C18 reversed-phase column (250 × 4.6 mm, particle size 5 μm) was used in this study. Acetonitrile and water in 1:1 (v/v) ratio was chosen as the mobile phase under a column temperature of 25°C. The detection wavelength was set at 280 nm with a flow rate of 1 mL/min. Method validation was performed according to the International Conference on Harmonization guidelines.
Results: HPLC method for the quantification of eugenol was successfully developed and validated. The method was validated in terms of linearity and range, accuracy, precision, specificity, robustness, detection limit, and quantitation limit.
Conclusions: The developed RP-HPLC-PDA could be successfully employed for the quantification of eugenol in nanoemulsion gel and nanoparticles.
Keywords: Accuracy; Precision; Specificity; Robustness; ICH guidelines
A green synthetic route for the production of highly stable silver nanoparticles using aqueous garlic extract is being reported for the first time. The silver nanoparticles were synthesized by exposing a mixture of 0.1M [Ag(NH3)2]+ and diluted aqueous garlic extract under bright sunlight for 15min. The garlic extract components served as both reducing and capping agents in the synthesis of silver nanoparticles while the sunlight acted as catalyst in the synthesis process. The synthesized nanoparticles were characterized using UV–visible (UV–vis) spectrophotometer; transmission electron microscopy (TEM), glancing angle X-ray diffraction (GA-XRD) and Fourier transform infra red (FTIR) spectrometry. The nanoparticles were found to be poly-dispersed in nature, spherical in shape and of 7.3±4.4nm in size. The FTIR analysis was suggestive of proteins as capping agents around the nanoparticles. The yield of synthesized nanoparticles was calculated to be approximately 80% by dry weight and 85% ICP-AES method. The synthesized silver nanoparticles exhibited good antibacterial potential against both Gram positive and Gram negative bacterial strains, as measured using well diffusion assay. Most importantly, the silver colloidal solutions thus synthesized were found to be stable for a very long period (more than a year) and retained their bactericidal potential.
IntroductionSitagliptin: From Green to Greener; from a Catalytic Reaction to a Metal-Free Enzymatic ProcessSaxagliptin: Elimination of Toxic Chemicals and the Use of a Biocatalytic ApproachArmodafinil: From Classical Resolution to Catalytic Asymmetric Oxidation to Maximize the OutputEmend: Redesigned for the Green ProcessGreening a Process via One-Pot or Telescoped ProcessingGreening a Process via Salt FormationMetal-free Organocatalysis: Applications of Chiral Phase-transfer CatalysisConclusions
References
Green synthesis and applications of gold nanoparticles are more fascinating research area due to their unique optical properties and high X-ray attenuation power. In this study, we have synthesized gold nanoparticles of uniform size (5 nm) with spherical shape. UV–vis spectroscopy, Transmission Electron Microscopy and Atomic Force Microscopy were employed to characterize the synthesized gold nanoparticles. The biomedical applications of the synthesized gold nanoparticles were carried out against most prevalent human fungal pathogen, Candida albicans. Broth micro dilution assay was used to determine minimum inhibitory concentration (MIC). We observed that 0. 5 mM concentration was effective in inhibiting the growth of fungal cells which was later confirmed by spot assay.
Herein, a straightforward method is proposed to synthesize gold nanoparticles (AuNPs) by using sucrose as reducing and capping agent in alkaline solution, under ultrasound irradiation and mild temperature conditions. By the implementation of a fully-automated flow-batch system, commanded by Arduino®, the generation of nanoparticles with tunable optical properties was possible, with localized surface plasmon resonance bands between 523 nm and 559 nm. The characterization of the obtained AuNPs was performed by UV–Vis and IR spectroscopy, transmission electron microscopy, dynamic light scattering and X-ray diffraction. The as-synthesized AuNPs, spherical in shape and with average size of 10 nm, were used for detection of ciprofloxacin based on the localized surface plasmon resonance band changes at 526 nm induced by the presence of this antibiotic. A solid phase extraction procedure, using C18 as sorbent material, was included for clean-up of samples and preconcentration of ciprofloxacin prior to analysis. The method was successfully applied to determine ciprofloxacin in the concentration range between 50 and 150 μg L⁻¹ with regression coefficients >0.99. The limits of detection were 12 and 16 μg L⁻¹ for detection of ciprofloxacin in surface water and honey samples, respectively. Recovery values were in the range of 89–110%, with relative standard deviation < 7%, showing the applicability of the synthesized particles.
We describe the application of Cistus incanus extract as a source of reducing, structure-directing and stabilizing agents in the fabrication of gold nanoparticles (GNPs) from tetrachloroauric acid solution. The synthesis resulted in the formation of nanostructures with highly extended surface area, resembling the shape of popcorn. Various ratios of plant extract volume to chloroauric acid volume were investigated in order to obtain nanoparticles with desired shapes having the narrowest size distribution. The synthesized nanoparticles were characterized using UV–Vis absorption spectroscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM). Multiphoton-excited luminescence (MPL) properties of plant extract synthesized popcorn-shaped gold nanoparticles were examined in comparison with gold nanostars synthesized chemically. The obtained results suggest that the GNPs synthesized using cistus extract may be useful imaging agents for multiphoton microscopy.
Development of an eco-friendly process for the synthesis of copper nanoparticles (CuNPs) is an important aspect in the field of nanotechnology. In recent years the utilization of secondary metabolites from plant leaf broth has emerged as a novel technology for the synthesis of various nanoparticles. In this report, copper nanoparticles were synthesized by the leaf broth of Azadirachta indica and effect of different reaction parameters such as precursor salt concentration, leaf broth percentage, temperature and pH of the medium on the conversion rate and morphology of the CuNPs were analyzed. The plant biomolecules induce the reduction of Cu²⁺ ions to CuNPs and also act as a capping and stabilizing agent. The formation of CuNPs was monitored by absorbance spectra of UV-visible spectrophotometer at different stages during the synthesis process. The biosynthesized CuNPs were characterized by different instrumental techniques and results described the particles are crystalline, cubical shape with the average size 48 nm and highly stable. The optimum conditions for synthesis are as follows: percentage of leaf broth 20%, [CuCl2] = 7.5 × 10⁻³ M, pH 6.6 and temperature 85 °C. The present study could prove to have an enormous impact in the immediate future to synthesize metallic nanoparticles on an industrial scale.
This book gives an overview of recent developments in RS and SERS for sensing and biosensing considering also limitations, possibilities and prospects of this technique. Raman scattering (RS) is a widely used vibrational technique providing highly specific molecular spectral patterns. A severe limitation for the application of this spectroscopic technique lies in the low cross section of RS. Surface-enhanced Raman scattering (SERS) spectroscopy overcomes this problem by 6-11 orders of magnitude enhancement compared with the standard RS for molecules in the close vicinity of certain rough metal surfaces. Thus, SERS combines molecular fingerprint specificity with potential single-molecule sensitivity. Due to the recent development of new SERS-active substrates, labeling and derivatization chemistry as well as new instrumentations, SERS became a very promising tool for many varied applications, including bioanalytical studies and sensing. Both intrinsic and extrinsic SERS biosensing schemes have been employed to detect and identify small molecules, nucleic acids and proteins, and also for cellular and in vivo sensing.
The Aedes aegypti L. mosquito transmits dengue and yellow fever, which cause millions of death every year. Dengue is a mosquito-borne viral disease that has rapidly spread worldwide particularly in countries with tropical and subtropical climates areas. The present study denotes a simple and eco-friendly biosynthesis of gold nanoparticles using Artemisia vulgaris L. leaf extract as reducing the agent. The synthesized gold nanoparticles were characterized by UV-Visible spectroscopy, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS), Zeta Potential (ZP), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDX). Solid state 13 C NMR was utilized to confirm the presence of larvicidal compound beta caryophyllene in the synthesized AuNPs. Larvicidal activity of the synthesized AuNPs was measured against A. aegypti over 12 and 24 hour exposure periods and compared with essential oil in various concentrations (25 ppm, 50 ppm, 100 ppm, 200 ppm and 400 ppm). After a 12 hour exposure period, the larvicidal activity of 3 rd instar larva by AuNPs showed LC 50 = 156.55 ppm and LC 90 = 2506.21 ppm, while and essential oil displayed LC 50 = 128.99 ppm and LC 90 = 1477.08 ppm. Larrvicidal activity of 4 th instar larva by AuNPs showed LC 50 = 97.90 ppm and LC 90 = 1677.36 ppm, while essential oil displayed LC 50 = 136.15 ppm and LC 90 = 2223.55 ppm. After a 24 hour of exposure period, larvicidal activity of 3 rd instar larva by AuNPs showed LC 50 = 62.47 ppm and LC 90 = 430.16 ppm and essential oil showed LC 50 = 111.15 ppm and LC 90 = 1441.51 ppm. The larvicidal activity of 4 th instar larva and AuNPs displayed LC 50 = 43.01 ppm and LC 90 = 376.70 ppm and for essential oil LC 50 = 74.42 ppm, LC 90 = 858.36 ppm. Histopathology of A. aegypti with AuNPs for 3rd and 4 th stage larvae after 24 hour exposure at the highest mortality concentration (400 ppm) showed that the area of the midgut, epithelial cells and cortex were highly affected. The present findings demonstrate that the biosynthesis of AuNPs using A. vulgaris leaf extracts could be an eco-friendly, safer nanobiopesticide and treatment against A. aegypti which could be used to combat of dengue fever. 2
Formation of blood clots, called thrombus, can happen due to hyper-coagulation of blood. Thrombi,
while moving through blood vessels can impede blood flow, an important criterion for many critical
diseases like deep vein thrombosis and heart attacks. Understanding mechanical properties of clot formation
is vital for assessment of severity of thrombosis and proper treatment. However, biomechanics
of thrombus is less known to clinicians and not very well investigated. Photoacoustic (PA) spectral
response, a non-invasive technique is proposed to investigate the mechanism of formation of blood
clots through elasticity and also differentiate clots from blood. Distinct shift (increase in frequency) of
the PA response dominant frequency during clot formation is reported. In addition, quantitative differentiation
of blood clots from blood has been achieved through parameters like dominant frequency and
spectral energy of PA spectral response. Nearly twofold increases in dominant frequency in blood clots
compared to blood were found in the PA spectral response. Significant changes in energy also help in
quantitatively differentiating clots from blood, in the blood. Our results reveal that increase in density
during clot formation is reflected in the PA spectral response, a significant step towards understanding
the mechanobiology of thrombus formation. Hence, the proposed tool, in addition to detecting thrombus
formation, could reveal mechanical properties of the sample through quantitative photoacoustic
spectral parameters.
Surface-enhanced Raman scattering (SERS) spectroscopy is based on the enormous enhancement of Raman scattering of molecules adsorbed on suitable metallic (mainly silver and gold) nanostructures. Two mechanisms contribute to the total enhancement: the electromagnetic one based on resonance excitations of surface plasmons in the metal and the chemical (or molecular) one increasing the polarizability of the molecule. Average enhancement factors are about 104–106 but even values about 1011 can be achieved in some cases. This chapter will briefly introduce the basics of SERS theory and some experimental aspects of SERS (choice of metal, distance dependence, selection rules, enhancement factors, “hot spots”, single-molecule SERS, resonant SERS). The SERS substrate plays a key role in any SERS application. An overview of SERS-active substrates employed in bioanalytical, biomolecular and medical SERS applications and their properties will be discussed. It includes nanoparticles in suspension, nanoparticles assembled and immobilized on solid substrates (bottom-up approach) and nanostructures fabricated directly on solid substrate (top-down approach). The related enhancing techniques (tip-enhanced RS—TERS, shell-isolated nanoparticles-enhanced Raman scattering—SHINERS, surface-enhanced infrared absorption—SEIRA and surface-enhanced fluorescence—SEF) will also be presented.
Nanomaterials have been influential to human life because of their interesting physical, chemical, optical and electronic properties. Recently, magnetic nanoparticles have attracted the interest of scientists and researchers, due to their possible potential applications in the area of Bio-medicals and clinical applications. The Cancer, a leading cause of death worldwide, has been anticipated to have 16 millions of new cases every year by the year 2020, causing 7 million deaths every year. In this context, Magnetic nanoparticles offer an exciting new alternative for Cancer treatment, with local heating of affected areas, by Hyperthermia therapy. The Iron oxide nanoparticles are ideal candidate for such biomedical applications, due to their well understood biocompatibility, chemical stability and inherent multi-functionality. In this article, we present a review over a variety of conventional and Green synthesis methodologies of Iron Oxide nanoparticle. Our primary focus, here, is to put up a critical comparison among the conventional and Green synthesis methods based on their physical and magnetic properties. The Green synthesis has been believed to be relatively cost effective, ecofriendly, pollutant free, rapid, one-step process, less time and energy consuming and providing homogenous composition, high yield with narrow size distribution compared to other techniques. However several issues such as environmental reactivity, self-aggregation etc. without losing the super paramagnetic behaviour need to be explored and rectified with a more controlled and efficient approaches in natural synthesis methodologies.
Renewable natural resources such as eugenol, furfurylamine, stearylamine and jute fiber were used to prepare polybenzoxazine composites. The purity of eugenol which is extracted from clove was confirmed by Gas Chromatography (GC). FT-IR, 1H and 13C-NMR spectroscopic analysis were used to determine the structure of eugenol and the benzoxazine monomers namely 6-allyl-3-furfuryl-8-methoxy-3,4-dihydro-2H-1,3-benzoxazine (EF-Bz) and 6-allyl-3-octadecyl-8-methoxy-3,4 dihydro-2H-1,3-benzoxazine (ES-Bz) synthesized from it. The curing analysis from Differential Scanning Calorimetric (DSC) analysis shows that the onset of curing is shifted to lower temperature (161 oC) for EF-Bz, when compared with ES-Bz (174 oC). The thermal stability analyzed from Thermogravimetric analysis (TGA) shows that the polybenzoxazine EF-Pbz has higher thermal stability (T5% = 361 oC) with that of ES-Pbz (T5% = 313 oC). The storage modulus, tensile and flexural strength of the EF-Bz/Jute fiber composite shows high value when compared ES-Bz/Jute fiber composites.
In this study, we have synthesized the gold nanoparticles by using Hibiscus rosa-sinensis, a medicinal plant. The gold
nanoparticles were synthesized rapidly by the involvement of microwave heating. By changing of plant extract
concentration, gold solution concentration, microwave heating time and power of microwave heating the
optimized condition was identified. The surface Plasmon resonance found at 520 nm confirmed the gold
nanoparticles synthesis. The spherical sized nanoparticles in the size range of 16–30 nm were confirmed by
Transmission Electron Microscope (TEM). The stability of the nanoparticles is very well proved in the invitro stability
tests. The biochemical like alkaloids and flavonoids play a vital role in the nanoparticles synthesis was identified
using the Fourier Transform Infrared Spectroscopy (FTIR). Combining the phytochemical and microwave heating,
the rapid synthesis of gold nanoparticles is the novel process for the medically applicable gold nanoparticles
production.
In the medical field, majority of the active ingredients exists in the form of solid particle (90% of all medicines). Nanotechnology had grabbed the attention of many scientists working in different aspects and gave them a vivid imagination in order to utilize the nanotechnology in an innovative way according to their needs. One of the major applications of nanotechnology is drug delivery through nanoparticles which is on boom for the researchers and gives a challenging environment for the researchers. Among them upcoming challenge is the use of inorganic nanoparticles for the drug delivery and related aspects. There is growing interests in usage of inorganic nanoparticles in medicine due to their size, and unique physical properties that make them different from other nanoparticulate systems. This review will lay special emphasis on the uniqueness of inorganic nanoparticles especially gold nanoparticles as a drug delivery vehicle and moreover will present a wide spread scenario of gold nanoparticles that has been used for treatment of life threatening diseases like cancer.
Essential oils from 25 species of medicinal plants were tested as mycelial growth inhibitors against six important pathogenic and toxinogenic fungal species. An agar dilution method was used for determination of the inhibitory effect namely on Fusarium oxysporum, Fusarium verticillioides, Penicillium expansum, Penicillium brevicompactum, Aspergillus flavus and Aspergillus fumigatus. All essential oils used in our experiment evidently affected growth of these fungi. Minimum inhibitory concentration (MIC) was evaluated in the case of five essential oils showing the most significant antifungal activity. The superior antifungal activity was finally proved on the base of MIC values in the case of Pimenta dioica. The chemical composition of P. dioica essential oil was determined by means of GC–MS analysis.
The synthesis of metal nanoparticles using algae has been unexplored, but it is a more biocompatible method than
the other biological methods. Metal nanoparticle synthesis using algae extract shows rapid and non-toxic process
which resulted to nano sizes having the greatest potential for biomedical applications. In this investigation, we
studied the green synthesis of gold nanoparticles using the algae extract of Turbinaria conoides. Green synthesis of
gold nanoparticles was preliminarily confirmed by color changing from yellow to dark pink in the reaction mixture,
and the broad surface plasmon resonance band was centered at 520 to 525 nm which indicates polydispersed
nanoparticles. Transmission electron microscopy and selected-area electron diffraction analysis show the
morphology and crystalline structure of synthesized gold nanoparticles with the size range of 6 to 10 nm. The four
strong diffraction peaks were observed by X-ray diffraction; it confirmed the crystalline nature of synthesized gold
nanoparticles. The carboxylic, amine, and polyphenolic groups were associated with the algae-assisted synthesized
gold nanoparticles which was confirmed using Fourier transform-infrared spectroscopy. This study eliminates the
use of chemical substances as reducing and stabilizing agent. Because it has natural several constituents which are
fucoidan and polyphenolic substances, it does a dual function as both reducing and stabilizing agent for
nanoparticles. Thus, algae-mediated synthesis process of biomedically valuable gold nanoparticles is a one-spot,
facile, convenient, large-scaled, and eco-friendly method.
The Caribbean tropical tree, Pimenta dioica has been used for a variety of human endeavors, such as in perfumery industry, food spice, as a natural pesticide, and in folk medicine. Discovered in Jamaica during the voyages of Christopher Columbus, the dried unripe berries of P. dioica also known as Allspice can be found in all continents with unique names in over 50 languages. Systematic investigation of aromatic constituents of Pimenta leaves and its unripe berries, Allspice, have resulted in discovery of many and novel aromatic compounds, mostly glycosides and polyphenols that show antibacterial, hypotensive, anti-neuralgic and analgesic properties. Recent studies have shown two of the known compounds isolated from Allspice, Eugenol and Gallic acid have selective antiproliferative and anti-tumor properties on human cancer cells and their animal models. New characterization of novel compounds such as Ericifolin from the aqueous extract of Allspice berries show potent anti-prostate cancer and anti-breast cancer properties that can be verified in vitro as well as in vivo. Considering its purity, mostly available as "organically grown" berries, availability at low cost, wide acceptance in culinary delights of many cultures world-wide, Allspice may have an additional space in most households, in their medicine cabinets.
We propose a sensing mechanism for detection of analytes that can specifically recognized. The sensor is based on closely-spaced chains of functionalized gold nanoparticles (NPs) immobilized on a waveguide surface, with the signal detected by evanescent waveguide absorption spectroscopy. The localized surface plasmon spectrum of a linear array of closely-spaced, hemispherical gold NPs is calculated using the discrete dipole approximation. The plasmon band is found to broaden to a nanowirelike spectrum when a dielectric coating is put on the particles, and the light polarization is along the NP chain. The origin of this broadening is shown to be the polarization-dependent overlap of the evanescent fields of adjacent NPs upon application of the dielectric coating. These features suggests a mechanism for biosensing with an improved sensitivity compared with traditional NP biosensor methods.
In recent years, the development of efficient green chemistry methods for synthesis of metal nanoparticles has become a major focus of researchers. They have investigated in order to find an eco-friendly technique for production of well-characterized nanoparticles. One of the most considered methods is production of metal nanoparticles using organisms. Among these organisms plants seem to be the best candidates and they are suitable for large-scale biosynthesis of nanoparticles. Nanoparticles produced by plants are more stable and the rate of synthesis is faster than in the case of microorganisms. Moreover, the nanoparticles are more various in shape and size in comparison with those produced by other organisms. The advantages of using plant and plant-derived materials for biosynthesis of metal nanoparticles have interested researchers to investigate mechanisms of metal ions uptake and bioreduction by plants, and to understand the
possible mechanism of metal nanoparticle formation in plants. In this review, most of the plants used in metal nanoparticle synthesis are shown.
Gold nanoparticles (AuNPs) are important components for biomedical applications. AuNPs have been widely employed for diagnostics, and have seen increasing use in the area of therapeutics. In this mini-review, we present fabrication strategies for AuNPs and highlight a selection of recent applications of these materials in bionanotechnology.
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