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Sensor Array (sensor + array)
Selected AbstractsSimultaneous Quantification of Heavy Metals Using a Solid State Potentiometric Sensor ArrayELECTROANALYSIS, Issue 8 2009Jesús Gismera Abstract A potentiometric sensor array of four nonspecific electrodes with solid-state membranes is developed and tested for simultaneous analysis of copper(II), mercury(II), and silver(I) ions. The cross-sensitivity responses of the sensors for these ions are evaluated. The array potentiometric signals are processed by partial least-squares regression (PLS) and back propagation artificial neural networks (ANN) to determinate analyte concentrations. The ANN configuration is optimized and two different training algorithms of the ANN are also evaluated. Best results are obtained when the potentiometric sensors are activated and the data are processed using ANN and the gradient descent adaptive algorithm. The system is used to quantify these heavy metals in synthetic samples and in dental amalgams with successful results. [source] A Colorimetric Sensor Array for the Detection of the Date-Rape Drug ,-Hydroxybutyric Acid (GHB): A Supramolecular ApproachCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2010Laurent Abstract ,-Hydroxybutyric acid (GHB), a colourless, odourless and tasteless chemical, has become one of the most dangerous illicit drugs of abuse today. At low doses, this drug is a central nervous system depressant that reduces anxiety and produces euphoria and relaxation, sedating the recipient. There is an urgent need for simple, easy-to-use sensors for GHB in solution. Here, we present a colorimetric sensor array based on supramolecular host,guest complexes of fluorescent dyes with organic capsules (cucurbiturils) for the detection of GHB. [source] Cross-Reactive Sensor Arrays for the Detection of Peptides in Aqueous Solution by Fluorescence SpectroscopyCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2010Sébastien Rochat Abstract A simple but powerful method for the sensing of peptides in aqueous solution has been developed. The transition-metal complexes [PdCl2(en)], [{RhCl2Cp*}2], and [{RuCl2(p -cymene)}2] were combined with six different fluorescent dyes to build a cross-reactive sensor array. The fluorescence response of the individual sensor units was based on competitive complexation reactions between the peptide analytes and the fluorescent dyes. The collective response of the sensor array in a time-resolved fashion was used as an input for multivariate analyses. A sensor array comprised of only six metal,dye combinations was able to differentiate ten different dipeptides in buffered aqueous solution at a concentration of 50,,M. Furthermore, the cross-reactive sensor could be used to obtain information about the identity and the quantity of the pharmacologically interesting dipeptides carnosine and homocarnosine in a complex biological matrix, such as deproteinized human blood serum. The sensor array was also able to sense longer peptides, which was demonstrated by differentiating mixtures of the nonapeptide bradykinin and the decapeptide kallidin. [source] Development of micropost force sensor array with culture experiments for determination of cell traction forcesCYTOSKELETON, Issue 7 2007Bin Li Abstract Cell traction forces (CTFs) are critical for cell motility and cell shape maintenance. As such, they play a fundamental role in many biological processes such as angiogenesis, embryogenesis, inflammation, and wound healing. To determine CTFs at the sub-cellular level with high sensitivity, we have developed high density micropost force sensor array (MFSA), which consists of an array of vertically standing poly(dimethylsiloxane) (PDMS) microposts, 2 ,m in diameter and 6 ,m in height, with a center-to-center distance of 4 ,m. In combination with new image analysis algorithms, the MFSA can achieve a spatial resolution of 40 nm and a force sensitivity of 0.5 nN. Culture experiments with various types of cells showed that this MFSA technology can effectively determine CTFs of cells with different sizes and traction force magnitudes. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Simultaneous Quantification of Heavy Metals Using a Solid State Potentiometric Sensor ArrayELECTROANALYSIS, Issue 8 2009Jesús Gismera Abstract A potentiometric sensor array of four nonspecific electrodes with solid-state membranes is developed and tested for simultaneous analysis of copper(II), mercury(II), and silver(I) ions. The cross-sensitivity responses of the sensors for these ions are evaluated. The array potentiometric signals are processed by partial least-squares regression (PLS) and back propagation artificial neural networks (ANN) to determinate analyte concentrations. The ANN configuration is optimized and two different training algorithms of the ANN are also evaluated. Best results are obtained when the potentiometric sensors are activated and the data are processed using ANN and the gradient descent adaptive algorithm. The system is used to quantify these heavy metals in synthetic samples and in dental amalgams with successful results. [source] Non-invasive detection of the metabolic burden on recombinant microorganisms during fermentation processes,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2001Th Bachinger Abstract Heterologous protein production is an important source of therapeutic products. Optimisation of such bioprocesses by adjustment of the expression rate of the heterologous protein to the biosynthetic capacity of the cell metabolism would benefit from an online method for monitoring the metabolic burden. In this study we evaluated the use of a chemical multi-sensor array for this purpose. Fermentations with a recombinant Escherichia coli strain expressing human superoxide dismutase (rhSOD) were monitored by the sensor array. The results of isopropyl-thiogalactopyranoside (IPTG)-induced expression were compared with fermentations with a plasmid-free strain. The overproduction of rhSOD, imposing a high metabolic burden on the plasmid-carrying cells, was distinctly and reproducibly observed by the multi-sensor array. The potential of this non-invasive method of non-specific metabolic burden monitoring is demonstrated by the results of the study. © 2001 Society of Chemical Industry [source] A research on determination of explosive gases utilizing cataluminescence sensor arrayLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4-5 2005Xiaoan Cao Abstract In this paper, we propose a model of a sensor array system, which consists of three cataluminescence sensors based on nanosized SrCO3, , -Al2O3 and BaCO3 as catalysts, for quantitative analysis of the explosive gases of propane, n -butane and iso-butane in a mixture. Six linear regression equations of the cataluminescence intensity vs. the gas concentrations in the range 2000,10 000 ppm were established from the sensor array system at two working temperatures, as the explosive gases show different sensitivity to the three sensors. The least squares method was employed for solving the simultaneous equations and quantifying the concentrations of the three components. The detection limits (3,) of propane, n -butane and iso-butane on SrCO3, , -Al2O3 and BaCO3 sensors are 50, 40 and 20 ppm, 80, 60 and 40 ppm, and 20, 10 and 5 ppm, respectively. The concentrations of two artificial samples containing the tertiary mixture were analysed with satisfactory results. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Diagnostic Utility of an Electronic Nose: Rhinologic ApplicationsTHE LARYNGOSCOPE, Issue 9 2002Erica R. Thaler MD Abstract Objective/Hypothesis The thesis explores the applicability of electronic nose technology in medical decision-making. Specifically, the studies undertaken in the thesis were designed to test the ability of the electronic nose to assist in diagnostic questions encountered in the field of rhinology. Study Design Three separate studies were undertaken. All involved analysis of specimens by the electronic nose, obtained either in vitro or in vivo: known matched sets of cerebrospinal fluid and serum, bacterial samples from known plated specimens, and culture swabs taken from patients suspected of having rhinosinusitis who also had a matched standard bacterial culture taken from the same site. The goal of analysis was to determine whether the electronic nose was able to identify or categorize specimens or groups of specimens. Methods Each specimen was tested using the organic semiconductor-based Cyranose 320 electronic nose. Data from the 32-element sensor array were subjected to principal-component analysis to depict differences in odorant patterns. Distinction of specimens was identified by calculation of Mahalanobis distance. Results The electronic nose was able to distinguish serum from cerebrospinal fluid in pure isolates as well as in isolates collected on small cottonoid pledgets at amounts of 0.2 mL or greater. It was also able to distinguish between control swabs and bacterial samples as well as among bacterial samples collected in vitro. Preliminary work suggests that it may be able to distinguish between presence and absence of bacterial infection in specimens collected on nasal swabs. Conclusions The electronic nose is able to distinguish reliably between cerebrospinal fluid and serum sampled in small amounts, may be able to identify presence and type of bacterial pathogen in vitro, and is able to identify presence or absence of bacteria on nasal swabs. Because this information is available immediately, the electronic nose may be a powerful new technology for diagnostic use, not only for rhinologic purposes but in many other aspects of medicine as well. [source] Aerobic batch cultivation in micro bioreactor with integrated electrochemical sensor arrayBIOTECHNOLOGY PROGRESS, Issue 1 2010Michiel van Leeuwen Abstract Aerobic batch cultivations of Candida utilis were carried out in two micro bioreactors with a working volume of 100 ,L operated in parallel. The dimensions of the micro bioreactors were similar as the wells in a 96-well microtiter plate, to preserve compatibility with the current high-throughput cultivation systems. Each micro bioreactor was equipped with an electrochemical sensor array for the online measurement of temperature, pH, dissolved oxygen, and viable biomass concentration. Furthermore, the CO2 production rate was obtained from the online measurement of cumulative CO2 production during the cultivation. The online data obtained by the sensor array and the CO2 production measurements appeared to be very reproducible for all batch cultivations performed and were highly comparable to measurement results obtained during a similar aerobic batch cultivation carried out in a conventional 4L bench-scale bioreactor. Although the sensor chip certainly needs further improvement on some points, this work clearly shows the applicability of electrochemical sensor arrays for the monitoring of parallel micro-scale fermentations, e.g. using the 96-well microtiterplate format. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] A Colorimetric Sensor Array for the Detection of the Date-Rape Drug ,-Hydroxybutyric Acid (GHB): A Supramolecular ApproachCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2010Laurent Abstract ,-Hydroxybutyric acid (GHB), a colourless, odourless and tasteless chemical, has become one of the most dangerous illicit drugs of abuse today. At low doses, this drug is a central nervous system depressant that reduces anxiety and produces euphoria and relaxation, sedating the recipient. There is an urgent need for simple, easy-to-use sensors for GHB in solution. Here, we present a colorimetric sensor array based on supramolecular host,guest complexes of fluorescent dyes with organic capsules (cucurbiturils) for the detection of GHB. [source] Cross-Reactive Sensor Arrays for the Detection of Peptides in Aqueous Solution by Fluorescence SpectroscopyCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2010Sébastien Rochat Abstract A simple but powerful method for the sensing of peptides in aqueous solution has been developed. The transition-metal complexes [PdCl2(en)], [{RhCl2Cp*}2], and [{RuCl2(p -cymene)}2] were combined with six different fluorescent dyes to build a cross-reactive sensor array. The fluorescence response of the individual sensor units was based on competitive complexation reactions between the peptide analytes and the fluorescent dyes. The collective response of the sensor array in a time-resolved fashion was used as an input for multivariate analyses. A sensor array comprised of only six metal,dye combinations was able to differentiate ten different dipeptides in buffered aqueous solution at a concentration of 50,,M. Furthermore, the cross-reactive sensor could be used to obtain information about the identity and the quantity of the pharmacologically interesting dipeptides carnosine and homocarnosine in a complex biological matrix, such as deproteinized human blood serum. The sensor array was also able to sense longer peptides, which was demonstrated by differentiating mixtures of the nonapeptide bradykinin and the decapeptide kallidin. [source] Electronic Tongues Employing Electrochemical SensorsELECTROANALYSIS, Issue 14 2010Manel del, Valle Abstract This review presents recent advances concerning work with electronic tongues employing electroanalytical sensors. This new concept in the electroanalysis sensor field entails the use of chemical sensor arrays coupled with chemometric processing tools, as a mean to improve sensors performance. The revision is organized according to the electroanalytical technique used for transduction, namely: potentiometry, voltammetry/amperometry or electrochemical impedance. The significant use of biosensors, mainly enzyme-based is also presented. Salient applications in real problem solving using electrochemical electronic tongues are commented. [source] Fabrication of a Macroporous Microwell Array for Surface-Enhanced Raman ScatteringADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Martina Zamuner Abstract Here, a colloidal templating procedure for generating high-density arrays of gold macroporous microwells, which act as discrete sites for surface-enhanced Raman scattering (SERS), is reported. Development of such a novel array with discrete macroporous sites requires multiple fabrication steps. First, selective wet-chemical etching of the distal face of a coherent optical fiber bundle produces a microwell array. The microwells are then selectively filled with a macroporous structure by electroless template synthesis using self-assembled nanospheres. The fabricated arrays are structured at both the micrometer and nanometer scale on etched imaging bundles. Confocal Raman microscopy is used to detect a benzenethiol monolayer adsorbed on the macroporous gold and to map the spatial distribution of the SERS signal. The Raman enhancement factor of the modified wells is investigated and an average enhancement factor of 4,×,104 is measured. This demonstrates that such nanostructured wells can enhance the local electromagnetic field and lead to a platform of ordered SERS-active micrometer-sized spots defined by the initial shape of the etched optical fibers. Since the fabrication steps keep the initial architecture of the optical fiber bundle, such ordered SERS-active platforms fabricated onto an imaging waveguide open new applications in remote SERS imaging, plasmonic devices, and integrated electro-optical sensor arrays. [source] On-line monitoring of wastewater quality: a reviewJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2001Wilfrid Bourgeois Abstract Real-time monitoring of wastewater quality remains an unresolved problem to the wastewater treatment industry. In order to comply with increasingly stringent environmental regulations, plant operators as well as instrument manufacturers have expressed the need for new standards and improved comparability and reliability of existing techniques. A review of currently available methods for monitoring global organic parameters (BOD, COD, TOC) is given. The study reviews both existing standard techniques and new innovative technologies with the focus on the sensors' potential for on-line and real-time monitoring and control. Current developments of biosensors, optical sensors and sensor arrays as well as virtual sensors for the monitoring of wastewater organic load are presented and the interests and limitations of these techniques with respect to their application to the wastewater monitoring are discussed. © 2001 Society of Chemical Industry [source] Light-induced immobilisation of biomolecules as an attractive alternative to microdroplet dispensing-based arraying technologiesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 19 2007Meg Duroux Abstract The present work shows how UV ,light-induced molecular immobilisation' (LIMI) of biomolecules onto thiol reactive surfaces can be used to make biosensors, without the need for traditional microdispensing technologies. Using ,LIMI,' arrays of biomolecules can be created with a high degree of reproducibility. This technology can be used to circumvent the need for often expensive nano/microdispensing technologies. The ultimate size of the immobilised spots is defined by the focal area of the UV beam, which for a diffraction-limited beam can be less than 1,,m in diameter. LIMI has the added benefit that the immobilised molecules will be spatially oriented and covalently bound to the surface. The activity of the sensor molecules is retained. Antibody sensor arrays made using LIMI demonstrated successful antigen binding. In addition, the pattern of immobilised molecules on the surface is not restricted to conventional array formats. The ultimate consequence of the LIMI is that it is possible to write complex protein patterns using bitmaps at high resolution onto substrates. Thus, LIMI of biomolecules provides a new technological platform for biomolecular immobilisation and the potential for replacing present microdispensing arraying technologies. [source] The selective processing of briefly presented affective pictures: An ERP analysisPSYCHOPHYSIOLOGY, Issue 3 2004Harald T. Schupp Abstract Recent event-related potential (ERP) studies revealed the selective processing of affective pictures. The present study explored whether the same phenomenon can be observed when pictures are presented only briefly. Toward this end, pleasant, neutral, and unpleasant pictures from the International Affective Pictures Series were presented for 120 ms while event related potentials were measured by dense sensor arrays. As observed for longer picture presentations, brief affective pictures were selectively processed. Specifically, pleasant and unpleasant pictures were associated with an early endogenous negative shift over temporo-occipital sensors compared to neutral images. In addition, affective pictures elicited enlarged late positive potentials over centro-parietal sensor sites relative to neutral images. These data suggest that a quick glimpse of emotionally relevant stimuli appears sufficient to tune the brain for selective perceptual processing. [source] Bacterial vaginosis , a laboratory and clinical diagnostics enigma,APMIS, Issue 3 2005Review article II Diagnosing bacterial vaginosis (BV) has long been based on the clinical criteria of Amsel et al., whereby three of four defined criteria must be satisfied. Though there are other criteria and scoring methods which function well in comparison (i.e. Nugent scoring), it is not certain that they will always identify the same category of patients. Point-of-care methods based on various combinations of microbial products, presence of RNA, or more complex laboratory instrumentations such as sensor arrays, have also been introduced for the diagnosis of BV. No method for diagnosing BV can at present be regarded as the best. It could be that , based partly on tacit knowledge on the part of the clinical investigators scoring in the clinic , various scoring systems have been chosen to fit a particular BV-related problem in a particular population. In this review we critically examine these pertinent issues influencing clinical scoring and laboratory diagnostics of BV. [source] Aerobic batch cultivation in micro bioreactor with integrated electrochemical sensor arrayBIOTECHNOLOGY PROGRESS, Issue 1 2010Michiel van Leeuwen Abstract Aerobic batch cultivations of Candida utilis were carried out in two micro bioreactors with a working volume of 100 ,L operated in parallel. The dimensions of the micro bioreactors were similar as the wells in a 96-well microtiter plate, to preserve compatibility with the current high-throughput cultivation systems. Each micro bioreactor was equipped with an electrochemical sensor array for the online measurement of temperature, pH, dissolved oxygen, and viable biomass concentration. Furthermore, the CO2 production rate was obtained from the online measurement of cumulative CO2 production during the cultivation. The online data obtained by the sensor array and the CO2 production measurements appeared to be very reproducible for all batch cultivations performed and were highly comparable to measurement results obtained during a similar aerobic batch cultivation carried out in a conventional 4L bench-scale bioreactor. Although the sensor chip certainly needs further improvement on some points, this work clearly shows the applicability of electrochemical sensor arrays for the monitoring of parallel micro-scale fermentations, e.g. using the 96-well microtiterplate format. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | |||||||||||||||||||