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General representation of OxPhos machinery in the mitochondria of eukaryotes. The ETC consists of four enzymes: complexes I (NADH-ubiquinol- oxidoreductase), II (succinate-ubiquinol oxidoreductase), III (ubiquinol-cytochrome c oxidoreductase) and IV (cytochrome c oxidase) located in the inner mitochondrial membrane. 97 Transfer of electrons (blue arrows) is mediated by coenzyme Q 10 (Q) and cytochrome c (cyt c ) and results in O 2 consumption at complex IV. The proton,
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Recent developments in the area of biological detection by optical sensing of molecular oxygen (O2) are reviewed, with particular emphasis on the quenched-phosphorescence O2 sensing technique. Following a brief introduction to the main principles, materials and formats of sensor technology, the main groups of applications targeted to biological det...
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Context 1
... at complex IV -cytochrome c oxidase. The ETC is largely responsible for the formation and maintenance of physiological gradients of potential, Dc m , and [H + ], DpH m , across the mitochondrial membrane, producing the proton motive force, pmf, which drives the synthesis of ATP molecules by complex V (ATP-synthase). This is shown schematically in Fig. ...
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... a result, by supplying the different substrates, specific inhibitors of complexes I-V and uncouplers ( Fig. 5) and measuring the OCR, one can extract detailed mechanistic information about the activity of different respiration states (states 1-4 respiration 98 ), the relative contribution of complex I and com- plex II pathways, the degree of coupling and spare respiratory capacity upon uncoupling, the mode of action of a drug on the ...
Citations
... In most of the cases the cladding is filled with air, and the PCF is designed with silicon as a base material. Comparatively, Because of its distinct structure, hollowcore PCFs have a number of advantages over conventional optical fibers, including no cutoff wavelength, good dispersion, high birefringence, an extensive mode field area, inadequate nonlinear effect, a high degree of design liberty, modest Fresnel reflection, minimal bending loss, and others (Wang et al. 2017;Chintoanu et al. 2006;Papkovsky and Dmitriev 2013;Park et al. 2016). ...
The gases which are generated in the industrial areas are very harm. Knowingly or unknowing the people who work near this hazardous area are affected lot and now it is the right time to detect these harmful gases in an efficient manner. In order to sense these hazardous gases a type of sensor that should sense these gases in an efficient manner, one such sensor is Photonic Crystal Fiber (PCF). The different gases such as SO3, Sicl4, CCl4, C10H16, Sncl4 are analyzed with the same Vertical PCF (V-PCF) and Horizontal PCF (H-PCF) gas sensor which was designed earlier for the detection of SO2 gas in an efficient manner. By maintaining the same design parameters different gases are sensed and compared with the SO2 gas outputs for the wavelength range of 0.8 μm to 1 μm. A sensitivity of 65.86% and 71.80% at 1 μm for C10H16, SnCl4, and other gases may be detected with the optimized V-PCF and H-PCF gas sensor. These gases are harmful and it will cause serious issues to the human beings. The different parameters such as sensitivity, effective mode area and attenuation are analyzed for different gases.
... Assay measurement range is 3-8 log(CFU/mL) (for E. coli or liquid food samples) or log(CFU/g) (for solid food samples). Although respirometry provides single cell sensitivity [27], TVC values below 25-250 counts are unreliable due to the sensitivity range of the reference plate-count To determine the optimal signal threshold which provides fast and accurate TVC quantification, we analyzed the effects of the different preset thresholds on the calculated E. coli concentrations ( Table 1). The accuracy was expressed as percent and calculated as 1-Error rate, where Error rate ¼ |TVC sensor -TVC ISO |/ TVC ISO, where TVC ISO represents the TVC count obtained by the reference ISO 4833 samples. ...
... Time to threshold values (TT, hours) obtained for the different concentrations of E. coli (3-8 log(CFU/mL)) using different thresholds(25,26,27,28,29, and 30 degrees Δϕ). ...
We describe a new sensor platform for simple on-site analysis of total aerobic viable counts (TVCs) in food samples, which uses disposable sealable plastic sachets with phosphorescent oxygen sensor inserts and liquid growth media. Food samples are collected, placed directly in the sachets, which are then sealed and incubated at 30 °C while monitoring (hourly or endpoint) sensor signals non-invasively with a commercial handheld reader FirestingO2. The growth of microbiota produces characteristic respiration profiles, from which sample initial TVC load is quantified: the Threshold Time (TT, in hours), when the sensor signal reaches the set signal threshold, is determined and calibration equation is applied to it to calculate sample TVC load. The initial calibration equation, which provides the conversion of measured TT values (hours) into TVC, was generated with pure Escherichia coli culture: log(CFU/g) = 8.30–0.60 *TT25 ° for signal threshold of 25 degrees phase. Another calibration equation, which provides a better representation of whole food microbiota, was generated with a panel of 90 different food samples: log(CFU/g) = 8.53–0.60 *TT25°. This simple sensor system shows good correlation with traditional plate counting TVC method (ISO 4833) and suitability for autonomous on-site or in-field operation. Time to result of 1–6 h provided by the sensor sachet system is more than seven time faster than for the standard method.
... These small particles are metal clusters, dots of quantum, and UCNP, which can serve as the fluorescent functional causes. These particles protect themselves by self-extinction (Li et al. 2018a, b, c;Liu et al. 2014Papkovsky 2013;Qian et al. 2016). The general disruption of these particles is summarized in form of a table (Table 1). ...
Majority of anticancer drugs possess a wide range of toxicities that are routinely administered to cancer patients. Further hypoxic condition too reduces the drug distribution in tumours affected their therapeutic efficacies. As a result, a major portion of cancerous drugs is distributed into nearby healthy tissues causing ill effect. In cancer without overdosing of drugs states as one of the most tedious issues for their treatment. Thus, the current chapter focuses on the novel concept of nanopoxia based on tumour hypoxia that utilizes photodynamic nanotherapy for the effective release of various therapeutic agents to accomplish accuracy in cancer therapy. Later, focuse on antimonene (Sb) therapy has been made that functions by switching to cytotoxic trivalent form to kill cancerous cells under hypoxic environment. Further, the study provides clarity of hypoxia grounded accurate tumour therapy by the development of nanotherapy that gives enormous opportunity to eradicate cancer.
... O 2 sensor based respirometry relies on dedicated sensor materials phosphorescence of which is reversibly quenched by dissolved O 2 . When introduced to samples either as soluble probes or solid-state coatings, they produce low phosphorescent signals at high O 2 levels and high phosphorescent signals when O 2 gets depleted (Papkovsky & Dmitriev, 2013). A number of different formats of O 2 respirometry and measurement modes allow for a diverse range of applications. ...
... A number of different formats of O 2 respirometry and measurement modes allow for a diverse range of applications. The traditional set-up is the simple air-tight cell, such as a cuvette with a stopper (Papkovsky & Dmitriev, 2013). Another format makes use of narrowbore capillary cuvettes (developed for real-time PCR) and measurements on a dedicated fluorescent detector (Zitova et al., 2010). ...
... Another format makes use of narrowbore capillary cuvettes (developed for real-time PCR) and measurements on a dedicated fluorescent detector (Zitova et al., 2010). Finally, respirometric measurements in the conventional 96-or 384-well plates are particularly advantageous, due to the miniaturisation, automation and high sample throughput of the corresponding TVC assays (O'Mahony, Green, Baylis, Fernandes, & Papkovsky, 2009;Papkovsky & Dmitriev, 2013). As a result, O 2 respirometry has had a number of food related applications, including the detection and enumeration of aerobic viable bacteria in food samples such as ready to eat salad mixes, fish and meat samples (Fernandes, Carey, Hynes, & Papkovsky, 2019;A. ...
In this study, rapid respirometric microbial testing was combined with 16S rRNA amplicon sequencing, to assess the composition of microbiota in a total of 64 samples of commercial beef, turkey, lamb and pork mince. The O2 sensor-based respirometry system, while producing the anticipated total aerobic viable counts (TVC) data and patterns for most samples, also revealed unusual (linear) respiration profiles for some samples, mostly lamb and pork mince. The TVC values for beef mince, produced by respirometry and calculated using the available calibration equation, correlated well with the conventional plate counting method, ISO 4833-1:2013, 2013, while for the other species the correlation was less good. These effects, not observed in previous studies employing various food matrices, require further investigation. Using the same samples (crude homogenates) as in respirometry, the whole microbiome was also analysed by 16S rRNA amplicon sequencing for each mince-type. The sequencing showed an overall decrease in alpha diversity over shelf-life, with lamb and pork mince maintaining a proportion of rare taxa. Some taxa exhibited significant changes in abundance over shelf-life and after the respirometric analysis, with beef mince exhibiting a decrease in aerobic bacteria and an increase in facultative anaerobes. Beta diversity was also seen to depend on mince-type. Thus, the combined use of respirometry and sequencing techniques shows promise as a useful and unique analytical approach for food quality and safety evaluation, However, more data points and in-depth analysis are required to back up the findings of this initial study.
... τ can vary and exist within dozens of pico-and nanoseconds to micro-and even milliseconds (delayed fluorescence of protoporphyrin IX). Three lifetime range 'domains', often requiring different types of detection equipment can be classified: 0.1 ~ 20 ns as 'a conventional FLIM', ~0.5-100 μs as phosphorescence lifetime imaging microscopy (PLIM, mostly for O 2 and thermally activated delayed fluorescence temperature imaging) and 100 ~ 1000 μs in macro-imaging, phosphorescence quenching microscopy (PQM) and delayed fluorescence-based O 2sensing [32][33][34]. Importantly, FLIM can be assayed in the visible as well as the near infrared ranges, permitting its application in microscopy as well as in small animal optical imaging [25,27,35,36]. The required lifetime resolution, light source and speed of acquisition dictate different engineering approaches to construct a wide variety of FLIM microscopes. ...
... Molecular oxygen is of paramount importance for tissue physiology within 3D context, since it is an essential substrate for aerobic respiration and oxidative phosphorylation (OxPhos) activity [32]. Diffusionlimited O 2 supply to the tissues is crucial for the development of niche-specific regions and function of stem cell niche(s). ...
... Higher O 2 levels result in shorter decay times, while the lower or absence of O 2 lead to measurement of unquenched longer lifetime (τ o ). The phenomenon of the quenched phosphorescence-based O 2 detection is often described by Stern-Volmer relationship and its modifications such as 'two-site model' [32]. A number of O 2 probes have been described for 3D tissue models and organoids: typically they all display large Stokes shifts with red (610 ~ 670 nm) or near-infrared emission (730-770 nm), with the lifetimes in range of 1 ~ 70 μs, showing mono-and double-exponential decay behaviour. ...
Organoid models have been used to address important questions in developmental and cancer biology, tissue repair, advanced modelling of disease and therapies, among other bioengineering applications. Such 3D microenvironmental models can investigate the regulation of cell metabolism, and provide key insights into the mechanisms at the basis of cell growth, differentiation, communication, interactions with the environment and cell death. Their accessibility and complexity, based on 3D spatial and temporal heterogeneity, make organoids suitable for the application of novel, dynamic imaging microscopy methods, such as fluorescence lifetime imaging microscopy (FLIM) and related decay time-assessing readouts. Several biomarkers and assays have been proposed to study cell metabolism by FLIM in various organoid models. Herein, we present an expert-opinion discussion on the principles of FLIM and PLIM, instrumentation and data collection and analysis protocols, and general and emerging biosensor-based approaches, to highlight the pioneering work being performed in this field.
... There have been many recent developments in diagnostic technologies that can measure a wide range of parameters related to a person's health, such as pressure/strain [24][25][26][27][28][29][30][31][32][33][34][35][36][37], temperature [27,[37][38][39][40], heartbeat/pulse rate [38,[41][42][43][44][45][46], blood oxygen [47], and respiration rate [48][49][50]. Moreover, emphasis is put on diagnostic devices to detect biomarkers observed in body fluids ( Fig. 1) such as urine [51], blood (plasma & serum) [52][53][54][55][56], saliva [57][58][59][60][61][62][63][64][65], cerebrospinal fluids [66,67], breath [68,69], and skin sweat [70][71][72]. ...
... Electrochemical methods and optical methods based on luminescence quenching and electrochemical methods enable in situ oxygen monitoring (Papkovsky and Dmitriev, 2013). The key advantages of electrochemical oxygen sensors include linear behavior, typically a one-point calibration method and compatibility of sensing electrode preparation with lithographic manufacturing processes. ...
Microphysiological systems (MPS) are drawing increasing interest from academia and from biomedical industry due to their improved capability to capture human physiology. MPS offer an advanced in vitro platform that can be used to study human organ and tissue level functions in health and in diseased states more accurately than traditional single cell cultures or even animal models. Key features in MPS include microenvironmental control and monitoring as well as high biological complexity of the target tissue. To reach these qualities, cross-disciplinary collaboration from multiple fields of science is required to build MPS. Here, we review different areas of expertise and describe essential building blocks of heart MPS including relevant cardiac cell types, supporting matrix, mechanical stimulation, functional measurements, and computational modelling. The review presents current methods in cardiac MPS and provides insights for future MPS development with improved recapitulation of human physiology.
... These small particles are metal clusters, dots of quantum, and UCNP, which can serve as the fluorescent functional causes. These particles protect themselves by self-extinction (Li et al. 2018a, b, c;Liu et al. 2014Liu et al. , 2017Papkovsky 2013;Qian et al. 2016). The general disruption of these particles is summarized in form of a table (Table 1). ...
Hypoxia is a condition in which there is a scarcity of oxygen. It is mainly associated with diseased circumstances, although it can also be a trait of healthy physiology. It is a pathophysiological condition linked to numerous ailments such as hyperglycemia and hypoglycemia inflammation, wounds, tumors, and so on. These conditions are all among the most detrimental to human health. Presently Rapid acknowledgment of this condition becomes essential. In the course of the evolution of clinical and preclinical investigation for the diagnosis of multiple diseases, molecular imaging has become a potent technique. A promising way to solve this drawback is the development of multifunctional hypoxia imaging nanoparticles that enhance the efficiency, specificity, and sensitivity of molecular imaging by providing molecular and functional information in an invasive manner under in vivo conditions. The most significant feature of Nanoparticles throughout the hypoxia imaging procedure is their higher penetration and retention implication with lengthy circulation capacity and easy encapsulation capability, generating them the most influential target for utilization in the biomedical application as a hypoxia imaging technique. Here, we concentrate on a recently generated nanoparticle that has been adopted as a tissue-level molecular imaging probe for numerous diseases.KeywordsHypoxiaNanoparticlesHypoxia imagingSpecificitySensitivity
... Optical O 2 respirometry is a group of techniques that uses phosphorescent O 2 sensing materials in the form of solid-state coatings or soluble probes to trace the dynamics of O 2 concentration in biological samples, usually containing living cells [57]. The long-decay emission of these materials is reversibly quenched by O 2 via a collisional (i.e., non-chemical) mechanism, and this process reduces sensor intensity and lifetime signals in a manner dependent on O 2 concentration [57][58][59]. ...
... Optical O 2 respirometry is a group of techniques that uses phosphorescent O 2 sensing materials in the form of solid-state coatings or soluble probes to trace the dynamics of O 2 concentration in biological samples, usually containing living cells [57]. The long-decay emission of these materials is reversibly quenched by O 2 via a collisional (i.e., non-chemical) mechanism, and this process reduces sensor intensity and lifetime signals in a manner dependent on O 2 concentration [57][58][59]. The relationship between the sensor signals and O 2 concentration is described by the Stern-Volmer equation [60]: ...
... Phosphorescence intensity measurements are used in some O2 sensing platforms, but they are more error-prone, unstable and difficult to operate. This is because intensity signals, I, are influenced by the fluctuation of the light source and detector, sensor positioning/measurement geometry, photobleaching and leaching of the dye, optical properties of the sample and instrument variability [57][58][59][60][61]. This in turn leads to large measurement errors, unstable calibrations and inaccurate results. ...
The current status of microbiological testing methods for the determination of viable bacteria in complex sample matrices, such as food samples, is the focus of this review. Established methods for the enumeration of microorganisms, particularly, the ‘gold standard’ agar plating method for the determination of total aerobic viable counts (TVC), bioluminescent detection of total ATP, selective molecular methods (immunoassays, DNA/RNA amplification, sequencing) and instrumental methods (flow cytometry, Raman spectroscopy, mass spectrometry, calorimetry), are analyzed and compared with emerging oxygen sensor-based respirometry techniques. The basic principles of optical O2 sensing and respirometry and the primary materials, detection modes and assay formats employed are described. The existing platforms for bacterial cell respirometry are then described, and examples of particular assays are provided, including the use of rapid TVC tests of food samples and swabs, the toxicological screening and profiling of cells and antimicrobial sterility testing. Overall, O2 sensor-based respirometry and TVC assays have high application potential in the food industry and related areas. They detect viable bacteria via their growth and respiration; the assay is fast (time to result is 2–8 h and dependent on TVC load), operates with complex samples (crude homogenates of food samples) in a simple mix-and-measure format, has low set-up and instrumentation costs and is inexpensive and portable.
... After the PDMS sensing film was proposed, more interferometric VOC sensors using PDMS were further investigated. Another instance is the simulation of the VOC sensor based on Fabry-Perot interference (FPI) with finite element method by Papkovsky and Dmitriev [13]. The FPI cavity was filled with PDMS sensing film. ...
Interferometric optical fiber sensors have become the preferred choice for ethanol vapor detection because of their high sensitivity and figure of merit. However, the response time of interferometric fiber optic ethanol vapor sensors is long. To address this issue, we experimentally investigated an ethanol vapor sensor based on a nematic liquid crystal (NLC) film embedded optical fiber Sagnac interferometer. The high birefringent NLC film, which worked as the sensing media of ethanol vapor for its absorption of ethanol vapor, was penetrated into the Sagnac ring to generate the spectral interference. The results showed that the measurement sensitivity of ethanol gas concentration reached 2.22 pm/ppm. The detection range was about 1210 -10000 ppm. Most importantly, the response time of the proposed sensor is only 15 seconds. The designed sensor, which showed the advantages of fast response, high sensitivity, and stability, could be a competitive candidate for ethanol vapor sensing.
