Dissertations / Theses on the topic 'Real-time biosensors'
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Ng, Shu Rui. "Electrochemical biosensors for real-time detection of angiogenesis." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/25625.
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Electrochemical biosensors have been made to detect the metabolic markers, pH, O2 and glucose, and nitric oxide (NO), the signalling molecule involved in angiogenesis. A novel three-dimensional (3-D) graphene/ionic liquid (IL) nanocomposite demonstrates highly sensitive detection of NO in phosphate buffered saline (PBS). An arginine-glycine-aspartic acid (RGD) peptide-functionalised biomimetic graphene film has been used as both a cell culture and sensing matrix to detect NO released by human umbilical vein endothelial cells (HUVECs) in real-time under acetylcholine (Ach) stimulation. The amount of NO released is dose-dependent and inhibited by NG-nitro-L-arginine methyl ester (L-NAME). A poly(ethyleneimine) (PEI)-coated anodically electrodeposited iridium oxide film (AEIROF) exhibiting super-Nernstian response to pH functions as miniature pH sensor for detecting acute changes in extracellular pH due to the interaction of porcine aortic ECs (PAECs) with fibronectin and thrombin. Thrombin causes dissolution of fibronectin, extracellular acidification of PAECs and a change in cell morphology from stretched to round cells. O2 and glucose biosensors based on a novel electropolymerised redox polymer are developed and prepared by one-step electropolymerisation of methylene blue (MB+) and pyrrole for the O2 biosensor, with the addition of glucose oxidase (GOD) for the glucose biosensor. The O2 biosensor demonstrates superior sensitivity towards dissolved O2 at atmospheric (atm) O2 concentrations and below and is insensitive to pH. The glucose biosensor exhibits direct electron transfer (DET) and is insensitive to pH from pH 6 to 8 in N2-purged PBS and from pH 4 to 8 in atm O2 PBS.
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Phairatana, Tonghathai. "Bioengineering of novel carbon-based biosensors for real-time biomedical use." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/58345.
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The aim of this thesis was to develop novel carbon-based biosensors and sensors for real-time metabolite and drug detection, to provide the next generation of medical devices which can give clinicians relevant chemical information in real-time at the patient bedside. An autocalibration system was developed using LabSmith programmable components to give precise fluid delivery and excellent temporal control of multiple liquid streams. This enables a 5-point calibration to be carried out using two solutions in 12 minutes. Systems using chitosan, poly(ethylene glycol)diglycidyl ether hydrogel, electrodeposition and selfassembly to immobilise enzymes on a combined needle electrode surface were studied and their performances were investigated using a microfluidic platform. The autocalibration system was combined with the graphene oxide-based biosensors in a microchip coupled with a microdialysis probe and was examined as a proof-of-concept clinical on-line analysis system. A reduced graphene oxide-based sensor was fabricated using a combined needle electrode for on-line neurotransmitter detection of dopamine. Its performance was compared with that of a platinum electrode. A microfluidic sensor based on a carbon nanotube-epoxy composite was fabricated to detect the presence of carboplatin (anti-cancer drug) in healthy tissue in real time during chemotherapy. Detection of carboplatin was carried out using differential pulse voltammetry firstly in a beaker, in which carbon nanotube-epoxy composite electrodes performed better than glassy carbon electrodes for oxidation of free purine bases and than DNA-modified carbon nanotube-epoxy composite sensors for detection of carboplatin. Carboplatin detection was then performed in a microfluidic platform. The methodology for on-line carboplatin detection was optimised in terms of the analysis time and for the repeated determination of carboplatin using the same electrode. Microdialysis and microfluidic techniques have been combined to give a proof-of-concept system real-time carboplatin detection using the carbon nanotube-epoxy composite sensors.
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Liu, Chang. "Localized Surface Plasmon Resonance Biosensors for Real-Time Biomolecular Binding Study." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/837.
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Surface Plasmon Resonance (SPR) and localized surface plasmon resonance (LSPR) biosensors have brought a revolutionary change to in vitro study of biological and biochemical processes due to its ability to measure extremely small changes in surface refractive index (RI), binding equilibrium and kinetics. Strategies based on LSPR have been employed to enhance the sensitivity for a variety of applications, such as diagnosis of diseases, environmental analysis, food safety, and chemical threat detection. In LSPR spectroscopy, absorption and scattering of light are greatly enhanced at frequencies that excite the LSPR, resulting in a characteristic extinction spectrum that depends on the RI of the surrounding medium. Compositional and conformational change within the surrounding medium near the sensing surface could therefore be detected as shifts in the extinction spectrum.
This dissertation specifically focuses on the development and evaluation of highly sensitive LSPR biosensors for in situ study of biomolecular binding process by incorporating nanotechnology. Compared to traditional methods for biomolecular binding studies, LSPR-based biosensors offer real-time, label free detection. First, we modified the gold sensing surface of LSPR-based biosensors using nanomaterials such as gold nanoparticles (AuNPs) and polymer to enhance surface absorption and sensitivity. The performance of this type of biosensors was evaluated on the application of small heavy metal molecule binding affinity study. This biosensor exhibited ~7 fold sensitivity enhancement and binding kinetics measurement capability comparing to traditional biosensors. Second, a miniaturized cell culture system was integrated into the LSPR-based biosensor system for the purpose of real-time biomarker signaling pathway studies and drug efficacy studies with living cells. To the best of our knowledge, this is the first LSPR-based sensing platform with the capability of living cell studies. We demonstrated the living cell measurement ability by studying the VEGF signaling pathway in living SKOV-3 cells. Results have shown that the VEGF secretion level from SKOV-3 cells is 0.0137 ± 0.0012 pg per cell. Moreover, we have demonstrated bevacizumab drug regulation to the VEGF signaling pathway using this biosensor. This sensing platform could potentially help studying biomolecular binding kinetics which elucidates the underlying mechanisms of biotransportation and drug delivery.
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Stengel, Gudrun. "Real time monitoring of DNA hybridization and replication using optical and acoustic biosensors." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971304572.
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Hong, Soonjin Barbee Kenneth A. "Quantitative analysis of cell-surface interactions and cell adhesion process in real-time /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2840.
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Canelle, Quentin. "Real Time Surface Plasmon Resonance Biosensors, a Powerful Technology to Assess Polyclonal Antibody Avidity." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/216754.
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The present research focused on the development of a new methodology to assess the strength of the interaction between vaccine antigens and elicited polyclonal antibodies through SPR biosensors. Quantifying the binding strength of polyclonal antibodies is of first importance to evaluate the quality of the vaccine as well as to increase the scientific knowledge of immune protection mechanisms. To now the development of such tool has been complicated by the non-specific binding caused by high protein abundance in the blood and serum samples but also by the way of interpreting the data resulting from multi-interaction events measured at the same time. At first, we unsuccessfully tried to segregate the individual affinity contribution of each antibody population by measuring the signal as the sum of singular interactions. Differentiation of the singular contribution would have needed the fulfillment of the “additivity” hypothesis, meaning that each antibody bind identically alone or in mixture with other antibody. This hypothesis was not met and mathematical assessment by the sum of singular contribution led to fitting results that did not reflect the biological reality. It was therefore decided to switch the analysis method and to measure the end association binding level reached by the different samples injected at the same specific antibody content. The dissociation behavior was interpreted by the percentage of binding after long and fixed dissociation time. In a first application, we compared the antibodies elicited by two different commercially available vaccines and we showed that the binding interaction was not concentration dependent as, highly different levels were reached when injecting identical antibody concentration. No statistical significant difference was observed between both vaccines. Research firstly focused on the decrease of the non-specific binding and we found that ionic strength was a key parameter, increasing the buffer salt concentration reduced the non-specific binding without diminishing the binding strength. The sample composition was also a key parameter and purifying the IgG allowed to decrease dramatically the undesired binding events. A second application aimed at showing the equivalence between two different antigen constructions for two antibodies population. Even if identical antigen level immobilization is a challenge, the methodology is completely suitable to perform a 2-dimensional comparison (ligand and analyte). A last application was dedicated to the comparison between D and Q-pan Flu vaccines, and results showed that there was no statistical evidence of significant differences between both vaccines. End association level correlated well with haemagglutination inhibition assay at least when serum samples were not diluted at the same antibody content. This last application also showed that throughput may be extended to more than 50 samples per 80 hoursDoctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
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Zelada, Guillén Gustavo Adolfo. "Ultrasensitive detection of pathogens in real-time. Potentiometric biosensors based on single-walled carbon nanotubes and aptamers." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/51768.
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Un gran nombre de plataformes de detecció biològica han incorporat materials
nanoestructurats com una estratègia per a millorar diversos paràmetres operacionals i de
qualitat tals com reduir els temps d'anàlisis i els límits de detecció. Les tècniques
electroquímiques de detecció es prefereixen sobre altres tècniques ja que presenten una sèrie
d'avantatges com a rapidesa, facilitat de maneig, cost reduït i la reduïda mida dels detectors
comercials. Entre les tècniques electroquímiques, les metodologies més simples, comunes i
més fàcils de transportar són aquelles basades en la potenciometria. La nova tendència
seguida amb els elèctrodes potenciomètrics d'estat sòlid representa una eina atractiva en
l'anàlisi de mostres líquides en temps real. No obstant això, fins avui ha estat difícil dur a terme
la detecció electroquímica directa de bacteris i proteïnes, sense utilitzar marcadors químics,
donat que les interaccions receptor‐bacteri i receptor‐proteïna no produeixen un senyal
elèctric mesurable. En aquesta tesi, es demostra per primera vegada la detecció
potenciomètrica en temps real de bacteris i proteïnes relacionades amb diverses malalties.
Aquesta tasca va ser duta a terme mitjançant el disseny d'una plataforma universal de detecció
utilitzant nanotubs de carboni com a transductors potenciomètrics i aptàmers com a elements
de reconeixement molecular. Les excel•lents propietats de transducció ofertes pels nanotubs
de carboni combinades amb la gairebé il•limitada possibilitat dels aptàmers de ser dissenyats
in vitro per reconèixer ions, proteïnes, virus i bacteris converteix aquesta plataforma en una
eina amb possibilitats inesgotables de detecció biològica en temps real.Un gran número de plataformas de detección biológica han incorporado materiales nanoestructurados como una estrategia para mejorar varios parámetros operacionales y de calidad tales como reducir los tiempos de análisis y los límites de detección. Las técnicas electroquímicas de detección se prefieren sobre otras técnicas debido a que presentan una serie de ventajas tales como rapidez, facilidad de manejo, coste reducido y el reducido tamaño de los detectores comerciales. Entre las técnicas electroquímicas, las metodologías más simples, comunes y más fáciles de transportar son aquellas basadas en la potenciometría. La nueva tendencia seguida con los electrodos potenciométricos de estado sólido representa una herramienta atractiva para el análisis de muestras líquidas en tiempo real. Sin embargo, hasta hoy ha sido difícil llevar a cabo la detección electroquímica directa de bacterias y proteínas sin ULTRASENSITIVE DETECTION OF PATHOGENS IN REAL‐TIME POTENTIOMETRIC BIOSENSORS BASED ON SINGLE‐WALLED CARBON NANOTUBES AND APTAMERS utilizar marcadores químicos, dado que las interacciones receptor‐bacteria y receptor‐proteína no producen una señal eléctrica medible. En esta tesis, se demuestra por primera vez la detección potenciométrica en tiempo real de bacterias y proteínas relacionadas con varias enfermedades. Esta tarea fue llevada a cabo mediante el diseño de una plataforma universal de detección utilizando nanotubos de carbono como transductores potenciométricos y aptámeros como elementos de reconocimiento molecular. Las excelentes propiedades transductoras de los nanotubos de carbono combinadas con la casi ilimitada posibilidad de los aptámeros de ser diseñados in vitro para reconocer iones, proteínas, virus y bacterias convierte esta plataforma en una herramienta con posibilidades inagotables de detección biológica en tiempo real.
Numerous biosensing platforms have incorporated nanostructured materials as a strategy for improving several performance and operational parameters such as reducing the limits of detection or the assay times in both pathogen and protein detection. Electrochemical sensing techniques are preferred over other detection methods because they present a series of advantages such as rapid response, ease of use, low‐cost and small sized commercial detectors. Among the electrochemical techniques, the simplest, most widespread and fieldportable methodologies are based on potentiometry. The new wave of potentiometric solidstate electrodes represents an attractive tool for real‐time bioanalysis in liquid samples. However, to date, it has been difficult to carry out the specific and direct electrochemical detection of whole living bacterial cells or disease‐related proteins without chemical labelling because the interaction receptor‐bacteria/receptor‐protein does not provide a measurable electrochemical signal. In this Thesis, the real‐time potentiometric detection of bacteria and disease‐related proteins is demonstrated for the first time. To accomplish such a challenging task, a novel and universal biosensing platform is designed using single‐walled carbon nanotubes as potentiometric transducers, and aptamers as biorecognition elements. The excellent potentiometric transduction properties of carbon nanotubes combined with the quasi‐unlimited capability of aptamers (RNA and DNA synthetic oligonucleotide segments) to be tailored in vitro against ions, proteins, viruses and bacteria converts such a platform into a
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Teerapanich, Pattamon. "Fluorescence-based nanofluidic biosensor platform for real-time measurement of protein binding kinetics." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30239/document.
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L'analyse cinétique d'interactions de protéines offre une multitude d'informations sur les fonctions physiologiques de ces molécules au sein de l'activité cellulaire, et peut donc contribuer à l'amélioration des diagnostics médicaux ainsi qu'à la découverte de nouveaux traitements thérapeutiques. La résonance plasmonique de surface (SPR) est la technique de biodétection optique de référence pour les études cinétiques d'interaction de molécules biologiques. Si la SPR offre une détection en temps réel et sans marquage, elle nécessite en revanche des équipements coûteux et sophistiqués ainsi que du personnel qualifié, limitant ainsi son utilisation au sein de laboratoires de recherche académiques. Dans ces travaux de thèse, nous avons développé une plateforme de biodétection basée sur l'utilisation de nanofentes biofonctionnalisées combinées avec une détection par microscopie à fluorescence. Ce système permet l'observation en temps réel d'interactions protéines-protéines et la détermination des constantes cinétiques associées, avec des temps de réponse optimisés et une excellente efficacité de capture. La fonctionnalité du système a été démontrée par l'étude des cinétiques d'interaction de deux couples modèles de différentes affinités : le couple streptavidine/biotine et le couple IgG de souris/anti-IgG de souris. Une très bonne cohérence entre les constantes cinétiques extraites, celles obtenues par des expériences similaires réalisées en SPR et les valeurs rapportées dans la littérature montre que notre approche pourrait être facilement applicable pour l'étude cinétique d'interactions de protéines avec une sensibilité allant jusqu'au pM, sur une large gamme de constantes de dissociation. De plus, nous avons intégré un générateur de gradient de concentrations microfluidique en amont de nos nanofentes, permettant ainsi des mesures simultanées de cinétiques d'interactions à différentes concentrations d'analyte en une seule expérience. Ce système intégré offre de nombreux avantages, tels qu'une réduction de la consommation des réactifs et des temps d'analyse par rapport aux approches séquentielles classiques. Cette technologie innovante pourrait ainsi être un outil précieux non seulement pour les domaines du biomédical et de la médecine personnalisée mais aussi pour la recherche fondamentale en chimie et biologieKinetic monitoring of protein-protein interactions offers fundamental insights of their cellular functions and is a vital key for the improvement of diagnostic tests as well as the discovery of novel therapeutic drugs. Surface plasmon resonance (SPR) is an established biosensor technology routinely used for kinetic studies of biomolecular interactions. While SPR offers the benefits of real-time and label-free detection, it requires expensive and sophisticated optical apparatus and highly trained personnel, thus limiting the accessibility of standard laboratories. In this PhD project, we have developed an alternative and cost-effective biosensor platform exploiting biofunctionalized nanofluidic slits, or nanoslits, combined with a bench-top fluorescence microscope. Our approach enables the visualization of protein interactions in real-time with the possibility to determine associated kinetic parameters along with optimized response times and enhanced binding efficiency. We have demonstrated the effectiveness of our devices through kinetic studies of two representative protein-receptor pairs with different binding affinities: streptavidin-biotin and mouse IgG/anti-mouse IgG interactions. Good agreement of extracted kinetic parameters between our device, SPR measurements and literature values indicated that this approach could be readily applicable to study kinetics of protein interactions with sensitivity down to 1 pM on a large scale of dissociation constants. In addition, we have incorporated a microfluidic gradient generator to our validated nanoslit device, which has allowed one-shot parallel kinetic measurements to be realized in a single-experiment. This integrated system provides advantages of diminished material consumption and analysis time over the conventional kinetic assays. We believe that this innovative technology will drive future advancements not only in the discipline of biomedical and personalized medicine, but also in basic chemical/biological research
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Brawner, Keith. "Modeling Learner Mood in Realtime through Biosensors for Intelligent Tutoring Improvements." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5774.
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Computer-based instructors, just like their human counterparts, should monitor the emotional and cognitive states of their students in order to adapt instructional technique. Doing so requires a model of student state to be available at run time, but this has historically been difficult. Because people are different, generalized models have not been able to be validated. As a person's cognitive and affective state vary over time of day and seasonally, individualized models have had differing difficulties. The simultaneous creation and execution of an individualized model, in real time, represents the last option for modeling such cognitive and affective states. This dissertation presents and evaluates four differing techniques for the creation of cognitive and affective models that are created on-line and in real time for each individual user as alternatives to generalized models. Each of these techniques involves making predictions and modifications to the model in real time, addressing the real time datastream problems of infinite length, detection of new concepts, and responding to how concepts change over time. Additionally, with the knowledge that a user is physically present, this work investigates the contribution that the occasional direct user query can add to the overall quality of such models. The research described in this dissertation finds that the creation of a reasonable quality affective model is possible with an infinitesimal amount of time and without “ground truth” knowledge of the user, which is shown across three different emotional states. Creation of a cognitive model in the same fashion, however, was not possible via direct AI modeling, even with all of the “ground truth” information available, which is shown across four different cognitive states.Ph.D.
Doctorate
Electrical Engineering and Computing
Engineering and Computer Science
Computer Engineering
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Shah, Niksha Chimanlal Meghji. "Construction and development of bioluminescent Pseudomonas aeruginosa strains : application in biosensors for preservative efficacy testing." Thesis, University of Hertfordshire, 2014. http://hdl.handle.net/2299/15592.
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Whole cell biosensors have been extensively used for monitoring toxicity and contamination of compounds in environmental biology and microbial ecology. However, their application in the pharmaceutical and cosmetics industries for preservative efficacy testing (PET) has been limited. According to several pharmacopoeias, preservatives should be tested for microbial activity using traditional viable count techniques; the use of whole cell microbial biosensors potentially provides an alternative, fast, and efficient method. The aim of the study was to construct and develop whole cell microbial biosensors with Pseudomonas aeruginosa ATCC 9027. Constitutive promoters: PlysS, Pspc, Ptat, Plpp and PldcC and the lux-cassette were inserted into plasmid pME4510 and transformed into P. aeruginosa ATCC 9027 cells to produce bioluminescent strains. Plasmids were found to be maintained stably (~50 copies per cell) throughout the growth and death cycle. The novel bioluminescent strains were validated in accordance with the pharmacopoeia using bioluminescence detection and quantification followed by comparison with the traditional plate counting method. The bioluminescent method was found to be accurate, precise and equivalent at a range of 103 – 107 CFU/mL, as compared with plate counting. Recovery of bacterial cells was quantified using bioluminescence; this method proved to be accurate with percentage recoveries between 70-130% for all bioluminescent strains. The method was also more precise (relative standard deviation less than 15%) than the traditional plate counting method or the ATP bioluminescent method. Therefore, the bioluminescent constructs passed/exceeded pharmacopoeial specified criteria for range, limit of detection, accuracy, precision and equivalence. Physiology of the validated bioluminescent strains was studied by assessing the growth and death patterns using constitutive gene expression linked with bacterial replication. Promoter strengths were evaluated at various stages of the growth and death pattern and related to promoter sequences. PlysS, Ptat and Plpp were relatively strong promoters whilst PldcC and Pspc were relatively weak promoters. Relative promoter strength decreased in the order of Plpp>Ptat>PlysS>PldcC>Pspc during the exponential phase whilst Ptat was stronger than Plpp during the stationary phase of growth. Plpp had its highest level of expression during the exponential phase, while Ptat had relatively stable lux expression during the stationary phase. Correlations between relative bioluminescence and CFU at 24 hours were greater than 0.9 indicating a strong relationship for all bioluminescent strains. Reduction in correlation coefficients to approximately 0.6 between relative bioluminescence and CFU and between relative fluorescence and CFU beyond 24 hours indicated that a certain proportion of cells were viable but non-culturable. Tat-pME-lux showed steady bioluminescence compared to CFU count (R>0.9) throughout 28 days of growth. Equivalence analysis showed no significant difference between the bioluminescence and plate count method throughout 28 days of growth for all five bioluminescent strains. Applicability of these novel bioluminescent strains was evaluated for preservative efficacy tests (PET) using bacterial replication and bioluminescence as a measure of constitutive gene expression. PET using benzalkonium chloride and benzyl alcohol showed no significant difference between the bioluminescent method and the plate count method. Good correlations between bioluminescence, CFU count and fluorescence were obtained for benzalkonium chloride (BKC) concentrations (R>0.9) between 0.0003% and 0.0025% against strains lysR25, lppR4 and tatH5. Similarly, good correlations (R>0.9) between the three parameters were obtained for benzyl alcohol (BA) concentrations between 0.125% and 2% against strains lysR25, lppR4 and tatH5. The bioluminescent method and traditional plate counting method were equivalent for concentrations of BKC (0.0003 - 0.02%) and BA (0.25 - 2%) during preservative efficacy tests. These bioluminescent constructs therefore are good candidates for selection for preservative efficacy testing. The bioluminescent method and traditional plate counting method were also found to be equivalent for construct tatH5 at a concentration of 0.125% BA. PET testing with BKC and BA showed that tatH5-pMElux (R>0.9) had consistently high correlation coefficients between CFU and relative bioluminescence. Together with the results from growth and death kinetics, where tatH5 showed the greatest constitutive expression, it can be concluded that P. aeruginosa ATCC 9027 tatH5-pMElux is the best construct for testing various antimicrobial agents. This study has shown that according to the pharmacopoeial requirements, the bioluminescent method is more accurate, precise and equivalent to the traditional plate counting method and therefore can be utilised instead of the traditional plate counting method for the purpose of preservative efficacy testing.
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Gowers, Sally. "Microfluidic biosensor systems for real-time in vivo clinical bioanalysis." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/51467.
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The aim of this thesis was to develop online biosensing systems for dialysate tissue metabo- lite detection in real time, to provide an insight into the health of tissue in various in vivo applications. An autocalibration system was developed using LabSmith programmable components to improve the accuracy of results obtained over long monitoring times. A method of col- lecting dialysate into storage tubes for online analysis while retaining temporal resolution was developed and validated. Microfluidic biosensor systems were developed for online measurement of glucose and lactate. One approach employed the use of biosensors, using a combined needle electrode with enzyme encapsulated in a hydrogel layer. The dynamic range of the biosensors was extended by adding an outer polyurethane layer. An alternative approach used automated syringe pumps and valves to develop a microfluidic system for in-flow enzyme addition to the dialysate stream. The existing rsMD system was applied for detection of tissue ischaemia during and after free flap surgery, by measuring dialysate glucose and lactate levels in real time. The system was able to detect flap failure, both during surgery and afterwards in the intensive therapy unit (ITU), much earlier than traditional methods. The rsMD system was adapted to enable monitoring of lactate levels in two dialysate streams and was applied for monitoring isolated porcine kidneys during two methods of cold preservation and subsequent re-warming. Significant differences in the lactate concentrations were observed between the two techniques. The system was extended for use with human transplant kidneys and with both porcine and human pancreases. A novel 3D printed wearable biosensor system was developed for direct integration with a clinical microdialysis probe. The system considerably improved the lag time and dispersional smearing compared with the existing rsMD system. The device was used in a proof-of-concept study with wireless potentiostats to monitor cyclists during exercise.
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Hondroulis, Evangelia. "Real-time Biosensor for the Assessment of Nanotoxicity and Cancer Electrotherapy." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/972.
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Knowledge of cell electronics has led to their integration to medicine either by physically interfacing electronic devices with biological systems or by using electronics for both detection and characterization of biological materials. In this dissertation, an electrical impedance sensor (EIS) was used to measure the electrode surface impedance changes from cell samples of human and environmental toxicity of nanoscale materials in 2D and 3D cell culture models. The impedimetric response of human lung fibroblasts and rainbow trout gill epithelial cells when exposed to various nanomaterials was tested to determine their kinetic effects towards the cells and to demonstrate the biosensor’s ability to monitor nanotoxicity in real-time. Further, the EIS allowed rapid, real-time and multi-sample analysis creating a versatile, noninvasive tool that is able to provide quantitative information with respect to alteration in cellular function.
We then extended the application of the unique capabilities of the EIS to do real-time analysis of cancer cell response to externally applied alternating electric fields at different intermediate frequencies and low-intensity. Decreases in the growth profiles of the ovarian and breast cancer cells were observed with the application of 200 and 100 kHz, respectively, indicating specific inhibitory effects on dividing cells in culture in contrast to the non-cancerous HUVECs and mammary epithelial cells. We then sought to enhance the effects of the electric field by altering the cancer cell’s electronegative membrane properties with HER2 antibody functionalized nanoparticles. An Annexin V/EthD-III assay and zeta potential were performed to determine the cell death mechanism indicating apoptosis and a decrease in zeta potential with the incorporation of the nanoparticles. With more negatively charged HER2-AuNPs attached to the cancer cell membrane, the decrease in membrane potential would thus leave the cells more vulnerable to the detrimental effects of the applied electric field due to the decrease in surface charge. Therefore, by altering the cell membrane potential, one could possibly control the fate of the cell. This whole cell-based biosensor will enhance our understanding of the responsiveness of cancer cells to electric field therapy and demonstrate potential therapeutic opportunities for electric field therapy in the treatment of cancer.
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Nguyen, Camha. "A tripartile biosensor for real-time SNSs detection in DNA hairpin motif." Honors in the Major Thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/485.
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The hybridization between two complementary strands of nucleic acid is the basis for a number of applications in DNA and RNA analysis, including in vivo RNA monitoring, microarrays, SNPs detection, and so on. The short oligonucleotide probes form Watson/Crick base pairs (A-T and G-C) with the analyzed nucleic acid. Molecular beacon (MB) probe is one of the most advantageous tools for nucleic acid analysis in real-time. A traditional MB probe consists of a DNA strand folded in hairpin motif with a fluorophore attached to the 5'end and a quencher attached to the 3' end. The loop segment is complementary to the analytes. Upon hybridization to a complementary single-stranded nucleic acid, MB probe switches to the elongated conformation, which separates the fluorophore from the quencher, resulting in high fluorescence signal. However, DNA or RNA folded in hairpin motifs are difficult to analyze by a conventional MB probes. Inefficient formation of the duplex between the secondary analyte and the MB probe results in low or undetectable fluorescent signal. In this project, we developed a tripartite probe consisting of one MB probe and two adaptor strands to genotype single nucleotide polymorphism (SNPs) in DNA hairpin motifs in real-time fluorescent assays. Each adaptor strand contains a fragment complementary to the analyte and a fragment complementary to an MB probe. One adaptor strand hybridizes to the analyte and unwinds its secondary structure, and the other strand forms stable complex only with the fully complementary analyte sequence. The tri-component probe promises to simplify nucleic acid analysis at ambient temperatures in such application as in vivo RNA monitoring and isothermal detection of specific DNA/RNA targets.B.S.
Bachelors
Medicine
Molecular Biology and Microbiology
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Binder, Michael. "Development of a Botrytis specific immunosensor : towards using PCR species identification." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/12110.
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Botrytis species affect over 300 host plants in all climate areas of the world, at both pre
and post-harvest stages, leading to significant losses in agricultural produce. Therefore,
the development of a rapid, sensitive and reliable method to assess the pathogen load of
infected crops can help to prescribe an effective curing regime. Growers would then
have the ability to predict and manage the full storage potential of their crops and thus
provide an effective disease control and reduce post-harvest losses.
A highly sensitive electrochemical immunosensor based on a screen-printed gold
electrode (SPGE) with onboard carbon counter and silver / silver chloride (Ag/AgCl)
pseudo-reference electrode was developed in this work for the detection and
quantification of Botrytis species. The sensor utilised a direct sandwich enzyme-linked
immunosorbent assay (ELISA) format with a monoclonal antibody against Botrytis
immobilised on the gold working electrode. Two immobilisation strategies were
investigated for the capture antibody, and these included adsorption and covalent
immobilisation after self-assembled monolayer formation with 3-dithiodipropionic acid
(DTDPA). A polyclonal antibody conjugated to the electroactive enzyme horseradish
peroxidase (HRP) was then applied for signal generation. Electrochemical
measurements were conducted using 3,3’, 5,5’-tetramethylbenzidine dihydrochloride /
hydrogen peroxide (TMB/H2O2) as the enzyme substrate system at a potential
of -200 mV. The developed biosensor was capable of detecting latent Botrytis infections
24 h post inoculation with a linear range from 150 to 0.05 μg fungal mycelium ml-1 and
a limit of detection (LOD) as low as 16 ng ml-1 for covalent immobilisation and
58 ng ml-1 for adsorption, respectively. Benchmarked against the commercially
available Botrytis ELISA kits, the optimised immuno-electrochemical biosensor showed
strong correlation of the quantified samples (R2=0.998) ... [cont.].
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Bouguelia, Sihem. "Développement de biopuces dédiées à la détection de bactéries pathogènes à faibles taux." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00872457.
Full textAbstract:
Détection et quantification de bactéries à faible taux par SPRi Résumé: Le protocole standard pour le diagnostic des bactéries dans le domaine médical et agro-alimentaire reste la culture microbienne, qui prend plusieurs jours pour identifier l'agent pathogène. Cependant, ces temps de latence ne sont pas compatibles avec l'urgence d'analyser rapidement la présence de bactéries pathogènes. Il ya un besoin croissant de vouloir développer de nouveaux outils pour identifier les bactéries pathogènes en un temps plus court. Afin atteindre cet objectif, la technologie de l'imagerie par Résonance des Plasmons de Surface (SPRi) a été utilisée avec succès pour la détection spécifique durant leur croissance des populations bactériennes en utilisant des protéines et/ou des anticorps comme molécule de bio reconnaissance des surfaces bactériennes. Ainsi, la détection spécifique de un à plusieurs milliers de pathogènes/ml peut être réalisé en quelques heures seulement. Dans le présent travail, plusieurs souches bactériennes ont été utilisées comme modèle : Streptococcus pneumoniae R6, Escherichia coli K12 ; ainsi que des agents pathogènes réels (Salmonella enteritidis) apportant la preuve que cette méthode peut être élargie à d'autres souches. Les résultats peuvent être quantitatifs par l'établissement d'une courbe d'étalonnage, permettant ainsi de remonter à la concentration initiale d'un échantillon contaminé. La stratégie développée au cours de ce travail se base sur le couplage simultané de la culture bactérienne et de la détection/identification spécifique, en utilisant l'imagerie SPR. Mots clés en français : Imagerie par résonance plasmonique de surface (SPRi), Streptococcus pneumoniae, E.coli K12, Salmonella enteritidis, croissance bactérienne, interactions, détection, capture, diagnostic, agro-alimentaire, pathogènes.
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Choong, Melissa Yen Ying. "Escherichia coli ATCC 8739 biosensor for preservative efficacy testing." Thesis, University of Hertfordshire, 2014. http://hdl.handle.net/2299/15623.
Full textAbstract:
The preservative challenge test is a regulatory requirement specified in various pharmacopoeias to determine the efficacy of preservatives. However, such testing is a labour-intensive repetitive task and often requires days before results can be generated. Microbial biosensors have the potential to provide a rapid and automated alternative to the traditional viable counting currently in use. However, the selection of appropriate promoters is essential. The bioluminescent reporter strains used in the current study comprise the Photorhabdus luminescence lux CDABE reporter genes under the control of five individual constitutive Escherichia coli promoters: outer lipoprotein (lpp); twin arginine translocase (tatA); lysine decarboxylase (ldc); lysyl t-RNA (lysS); and ribosomal protein (spc). The promoter plus lux CDABE constructs were cloned, ligated into the plasmid vector pBR322 and transformed into E. coli ATCC 8739. The bioluminescence intensity in the decreasing order of constitutive promoter was lpp > spc> tatA> ldc > lysS. The five biosensor strains tested successfully in PET assays and demonstrated accuracy with a minimum detection limit of 103 CFU/ml, a detection range of 6 orders magnitude, and yielded equivalent results to methods currently recommended by the pharmacopoeias. The bioluminescent biosensors were used to monitor the efficacy of preservatives; sorbic acid at concentrations of 0.031% to 0.2% at pH 5.0, and benzalkonium chloride at concentrations of 0.0062% to 0.00039% alone and in combination with 0.03% EDTA. The 99.9% percentage of bioluminescence reduction of tatA-lux, ldc-lux, lysS-lux, and spc-lux was statistically equivalent to the 3 log10 CFU/ml reduction as required by the Pharmacopeias’. Strong significant correlations between bioluminescence and the methods recommended by the pharmacopoeias were obtained when the biosensor strains were challenged with preservatives, for all except lpp-lux E. coli. The bioluminescence expressed by the lpp-lux biosensor was significantly lower during long-term stationary phase than it was for any of the other biosensors and was also significantly lower than for any of the other biosensors in the presence of preservatives. Since the plasmid copy number and viable counts for lpp-lux did not change under these conditions, it suggests that perhaps lpp-lux was down regulated under stress conditions. There were no statistically significant differences between the results of the bioluminescence assays and the results of the viable count and ATP chemiluminescence assay. Virtual foot printing (using Regulon DB database) demonstrated that two crp binding sites overlapping the -10 regions are located on the negative strand of the lysS promoter sequences and that one crp binding site is located in lpp. The biosensor strains ldc-lux exhibited levels of bioluminescence per cell significantly lower than spc in the presence of preservatives whilst there was a significant increase in bioluminescence per cell by tatA-lux under alkaline conditions (pH 8.9) during long-term stationary phase. Amongst the five biosensor strains tested in the current work, it was determined that the spc-lux strain would be the most attractive candidate for further work, since the bioluminescence expressed per cell was significantly greater, by 10-1000 times, than that expressed by the other four promoters when challenged with the preservatives tested with excellent significant correlations between bioluminescence expression and viable counts in the PET assays with the various preservatives in this study (R2: 8.79-1.00). The bioluminescent biosensor strains showed no statistical differences from the control strains (wildtype E.coli ATCC 8739 and E.coli carrying a promoterless [pBR322.lux] for adneylate energy charge (AEC), plasmid copy number (PCN) bioluminescence or viable counts over 28 days. The emission of bioluminescence by the four bioreporter strains across 28 days is reflected by the stability of PCN with correlations of 0.78-0.90, except for lpp-lux with R2: 0.59. The following promoter elements were found likely to assist greater expression of bioluminescence: an A+T level of approximately 50% between the -40 and -60 regions (the UP element); a G+C level of approximately 50% within the -10 and +1 regions; the extended -10 region and -10 region of consensus sequence RpoD (σ70/D).
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Elsom, Jacqueline. "Development of a quartz crystal based biosensor for real-time monitoring of particulate cell interactions." Thesis, University of Brighton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412096.
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Rawson, Frankie James. "The design, development and application of a novel electrochemical biosensor/sensor system for the real-time monitoring of in-vitro cell toxicity." Thesis, University of the West of England, Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557140.
Full textAbstract:
In recent years there has been a reported requirement by the pharmaceutical and agrochemical industry that there is a need to monitor In vitro cell toxicity in real time, and also a necessity for using cell models that mimic the In vivo situation more closely. The aim of this project was to provide a solution for these key issues set out above. This was achieved by developing, characterising and implementing the use of electrochemical micro-biosensors and micro-sensors manufactured from screen printed electrodes. These were then used for monitoring cytotoxicity in HepG2 spheroids which mimic more closely their corresponding organ in vivo. In chapter two a new method of using screen-printed carbon electrodes (SPCEs) incorporating the electrocatalyst cobalt phthalocyanine (CoPC) for the manufacture of microband electrodes for hydrogen peroxide detection is described. Tubular microband electrode (TMBEs) fabricated using an organic based ink displayed superior properties over plain microbands. TMBEs were demonstrated to display steady state currents which, is indicative of microelectrode behaviour. The current density values obtained from the voItammogram was compared to that obtained for a conventional sized CoPC-SPCE, and the values were 5618 and 35.65 μA cm -2, respectively. Cyclic voltammetry was carried out for the same electrodes; using 7 mM H202 prepared in phosphate buffer at scan rates between 1 and 50 mV s-I and no significant increase in current response was observed. The application of these tubular microband CoPC-SPCEs, to the measurement of H202 using chronoamperometry was investigated. A calibration study was performed and the plot showed a sensitivity value of 252 μA mM-1 cm-2 and a lower detection limit of70 μM. Although this data was promising for later biosensor construction it is known that the organic based ink used to screen-print the sensors would not allow for direct incorporation of the enzyme which would be later incorporated to allow for monitoring of biomarkers important in cell toxicity. Therefore, in chapter three microband electrodes screen-printed using a water based ink were investigated which would allow for enzyme incorporation in to the inks subsequent to screen-printing and thus allowing for the formation of biosensors. Plain microband electrodes fabricated from this water based carbon ink displayed superior characteristics over the TMBEs fabricated from the same ink for hydrogen peroxide monitoring, this included higher current density values, stir independence and these were more reproducible. Therefore the plain microband was the design choice for future sensor and biosensor construction. In chapter three and four screen-printed sensors and biosensors were constructed using a water based ink with the incorporation of lactate oxidase or glucose oxidase. In chapter 5, organic based carbon ink incorporating Meldola's blue was added prior to printing allowing for a one step print process. These were then cut forming microband biosensors and sensors, allowing for the monitoring of the analytes lactate, glucose and NADH respectively. Lactate microband biosensors could monitor lactate and was measured over a dynamic range of 1-10 mM which was linear up to 6mM; a calculated lower limit of detection of 289 μM was ascertained. Microband sensors for glucose determination were used and could measure glucose over the concentration range 1-14 mM. A linear range was obtained up to 6 mM glucose (y = 3.05x) giving a R2 value of 0.99 and an intra-electrode coefficient of variation over this range of 10%. A sensitivity value over this range of 3.1 nA mM-I was obtained with a theoretical lower detection limit of 258 μM. Microband sensors incorporating the electrocatalyst were used to measure NADH over a dynamic range 0.2-3.5 mM. A linear range was obtained up to 400 IlM NADH (y = 0.0076x + 0.7665) giving a R2 value of 0.999 and a typical inter-electrode coefficient of variation over this range of 18% (n=5). A sensitivity value over this range of 7.6 nA mM-I was obtained with a theoretical lower detection limit of 63 IlM. The microband screen-printed sensors for lactate, glucose and NADH were then used to monitor cytotoxicity by monitoring the release of their corresponding analyte. This was performed over a 24 hour period in which HepG2 spheroids were exposed to the model hepatotoxin galactosamine. The results provide proof of principle that the developed electrochemical sensors could follow the above biomarkers which were good indicators of cell induced toxicity caused by the galactosamine.
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Bracewell, Daniel Gilbert. "The use of an optical biosensor for the real-time monitoring of product and product variants in biological process streams and applications for control." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314156.
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Qi, Ziming. "Real-time adaptive noise cancellation for automatic speech recognition in a car environment : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Engineering at Massey University, School of Engineering and Advanced Technology, Auckland, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/812.
Full textAbstract:
This research is mainly concerned with a robust method for improving the performance of a real-time speech enhancement and noise cancellation for Automatic Speech Recognition (ASR) in a real-time environment. Therefore, the thesis titled, “Real-time adaptive beamformer for Automatic speech Recognition in a car environment” presents an application technique of a beamforming method and Automatic Speech Recognition (ASR) method. In this thesis, a novel solution is presented to the question as below, namely: How can the driver’s voice control the car using ASR? The solution in this thesis is an ASR using a hybrid system with acoustic beamforming Voice Activity Detector (VAD) and an Adaptive Wiener Filter. The beamforming approach is based on a fundamental theory of normalized least-mean squares (NLMS) to improve Signal to Noise Ratio (SNR). The microphone has been implemented with a Voice Activity Detector (VAD) which uses time-delay estimation together with magnitude-squared coherence (MSC). An experiment clearly shows the ability of the composite system to reduce noise outside of a defined active zone. In real-time environments a speech recognition system in a car has to receive the driver’s voice only whilst suppressing background noise e.g. voice from radio. Therefore, this research presents a hybrid real-time adaptive filter which operates within a geometrical zone defined around the head of the desired speaker. Any sound outside of this zone is considered to be noise and suppressed. As this defined geometrical zone is small, it is assumed that only driver's speech is incoming from this zone. The technique uses three microphones to define a geometric based voice-activity detector (VAD) to cancel the unwanted speech coming from outside of the zone. In the case of a sole unwanted speech incoming from outside of a desired zone, this speech is muted at the output of the hybrid noise canceller. In case of an unwanted speech and a desired speech are incoming at the same time, the proposed VAD fails to identify the unwanted speech or desired speech. In such a situation an adaptive Wiener filter is switched on for noise reduction, where the SNR is improved by as much as 28dB. In order to identify the signal quality of the filtered signal from Wiener filter, a template matching speech recognition system that uses a Wiener filter is designed for testing. In this thesis, a commercial speech recognition system is also applied to test the proposed beamforming based noise cancellation and the adaptive Wiener filter.
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Li, Chung-Yu, and 李昌昱. "Fabrication of ARROW-B SPR Biosensors and Using the Biosensors for Real-Time Detection of Proteinase Activity." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/84173429325374892270.
Full textAbstract:
碩士國立交通大學
電子工程系所
98
In this thesis, the fabrication process of ARROW-B SPR sensors used in aqueous environment has been investigated. The sensors are used for real-time detection of proteinase activity. ARROW-B waveguide with a thick guiding region provides efficient coupling with a single-mode fiber. The waveguides in front and rear of the SPR sensing region have symmetric cladding structure to improve the immunity against environmental changes, and the sensing region is configured with a liquid flow channel which enables biomolecules to adhere to the Au surface. Then we apply the sensors in real-time detection of the degradation of gelatin by MMP2. We could tell from the SPR curve that ONO-4817 of 186.88 nM could totally inhibit the activity of 0.5 μl MMP2 of 0.1 μg/μl.
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Chang, Su-Wei, and 張書維. "Fabrication of ARROW-B SPR Biosensors and Using the Biosensors for Real-Time Detection of Immunoassay and Proteinase Activity." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/59823923732929727781.
Full textAbstract:
碩士國立交通大學
電子研究所
100
In this study, a Si-based ARROW-B SPR biosensor used in aqueous environment has been investigated. The ARROW-B SPR biosensor was proposed to provide a label-free, real-time detection, and highly surface-sensitive platform to detect the bimolecular interactions. Modal characteristics of ARROW-B were analyzed with simulation and the devices were designed for obtaining optimum sensitivity in aqueous environment. The ARROW-B waveguide with a thick guiding region provides efficient coupling with a single-mode fiber. The waveguide in the front and the rear of the SPR sensing region have a symmetric cladding structure which can improve the immunity against environmental changes and elimmate the effect on the light propagation characteristics. The sensing region was configured with a liquid flow channel which assists bioagents in attaching to the surface for reaction. The sensors were applied in real-time detections of immunoassay and proteinase activity. In the experiments, the real-time immunoassay detection for mouse IgG and anti-mouse IgG antibody as well as the proteinase activity detection for trypsin, MMP2, and MMP7 were performed, which have verified the feasibility of devices.
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Tsai, Chen-Yu, and 蔡承鈺. "Fabrication of ARROW-B SPR Biosensors and Its Application to Real-Time Immunoassay." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/20747102193370048293.
Full textAbstract:
碩士國立交通大學
電子工程系所
96
In this thesis, an ARROW-B SPR sensor used in aqueous environment has been investigated. ARROW-B waveguide with a thick guiding region provides efficient coupling with a single-mode fiber, and the propagation behavior can be modulated by adjusting the structure. Modal characteristics of ARROW-B are analyzed with simulation and designed for obtaining optimum sensitivity in aqueous environment. The waveguides in front and rear of the SPR sensing region have symmetric cladding structure to improve the immunity against environmental changes, and the sensing region is configured with a liquid flow channel which assists bioagents in attaching to the gold surface for reaction. Then we submit the sensors in application to real-time immunoassay, and attain 10-10 g/ml of concentration of mouse IgG in detection limit. The power differences have a approximately linear relation with the concentration of mouse IgG between 10-10 and 10-7 g/ml. Using the Atomic Force Microscopy, the biomolecules binding to the gold surface are visualized. Finally, the specific immunoassay of antibody-antigen conjugate is demonstrated.
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Lin, Zheng-Wen, and 林政文. "Fabrication of ARROW-B SPR Biosensors for Real-Time Detection of Protein Kinase A Activity." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/24373859375112653168.
Full textAbstract:
碩士國立交通大學
電子研究所
100
In this study, surface plasmon resonance (SPR) biosensors with antiresonant reflecting optical waveguide of type B (ARROW-B) structure have been investigated. The ARROW-B SPR biosensors was proposed to provide label-free, high-throughput, and highly sensitivity characteristics to detect the biomolecular interaction for the aqueous environment in real time. Moreover, The ARROW-B waveguide with a thick guiding region provides efficient coupling with a single-mode fiber. Modal characteristics of ARROW-B are analyzed with simulation and designed for obtaining optimum sensitivity in aqueous environment. The design and fabrication process of the ARROW-B sensor chips are described and discussed. For the bioassay experiments, the protein kinase A (PKA) activity is detected. PKA is a kind of enzyme, and its function is to catalyze the phosphorylation. The phosphorylation is common and indispensable in metabolism. In summary, the measurement results have shown that the ARROW-B SPR biosensors can be applied to detect the PKA activity quantitatively in real time.
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Stengel, Gudrun [Verfasser]. "Real time monitoring of DNA hybridization and replication using optical and acoustic biosensors / vorgelegt von Gudrun Stengel." 2004. http://d-nb.info/971304572/34.
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Huang, Chi-Chieh, and 黃繼傑. "Real-Time Detection of α-Thrombin Binding to Single-Strand DNA Aptamers and Dengue Virus DNA Hybridization by ARROW-B SPR Biosensors." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/73575633967046751075.
Full textAbstract:
碩士國立交通大學
電子工程系所
96
In this thesis, an antiresonant reflecting optical waveguide of type B (ARROW-B) surface plasmon resonance (SPR) biosensor operating in the aqueous environment has been investigated. The ARROW-B SPR biosensor is proposed to provide a label-free, high-throughput and highly surface-sensitive platform to detect the bimolecular interactions in real time. The design and fabrication process of the ARROW-B SPR sensor chips are described and discussed. Besides, the primary analytes for the bioassay experiments are divided into two categories based on different binding characteristics. First, the real-time detection of α-thrombin binding to ssDNA aptamers was under in-depth investigation. The gold nanoparticles modified with anti-thrombin antibodies were employed to bind to the α-thrombins for signal amplification. The detection limit of this biosensor to α-thrombin was measured at 1 pM level, which was comparable to that of the Biacore 3000 system but at much lower cost. Second, the real-time detection of dengue virus ssDNA hybridization was studied. The dengue virus DNA probe was modified with a thiol group at one end to achieve effective immobilization on the Au surface, while the DNA target utilized the complementary sequence to bind to the immobilized probe. In summary, the measurement results have shown that the ARROW-B SPR biosensors can be applied to detect the ssDNA aptamer/α-thrombin interaction and dengue virus ssDNA hybridization both quantitatively and qualitatively in real time.
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Gao, Shiuan-Huei, and 高炫揮. "Label-free and real-time protein biosensor." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/70401169843752291048.
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Liu, Wen-Hsing, and 劉紋杏. "Label-free and real-time electrical biosensor." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/97539236198040691241.
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Yu, Chih-Jen, and 游智仁. "Fiber Optic Biosensor For Real Time Monitoring Protein Binding Kinetics." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/45312132106992113590.
Full textAbstract:
碩士國立陽明大學
生醫光電工程研究所
92
In cell biological research, protein control mediates many of biological activities of cells. Most of proteins function in association with other protein to gain an cellular function. Therefore protein-protein interaction becomes essential to understand biological activities that have been studied by determination of kinetic constants. The fiber optic biosensor is one of the easiest way to setup to study the kinetics of protein-protein interaction in real time where the optical fiber is disposable in the measurement. Then fiber optic biosensor is a novel equipment for kinetic constants measurement. C-reactive protein (CRP), an acute phase protein of inflammation is related to the risk factor for cardiovascular diseases. In recently study, a different expression of CRP, the modified CRP (mCRP), shows more dependence on cardiovascular diseases significantly than CRP. In this study, a fiber optic biosensor was setup in order to determine mCRP/anti-CRP binding kinetics to investigate the condition between mCRP and the risk factor of cardiovascular diseases quantitatively. The experimental result will be useful for the purpose of earlier diagnosis of the cardiovascular diseases.
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Yu, Yuh-Yan, and 游育諺. "Use of Piezoresistive Microcantilever Biosensor to Real-Time Monitor Bio-molecules." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/98595062607123148030.
Full textAbstract:
碩士國立臺灣大學
應用力學研究所
94
Bio-sensing tools have been moving towards miniaturization, high sensitivity, portability and wireless networking. While fluorescent labeling of nucleic acids is becoming a standard procedure, protein labeling techniques are not yet as well established. The purpose of this paper is to demonstrate a novel reusable biosensor which achieves the continuous label-free recognition of biological substances in real-time, which based on the nanomechanics of a piezoresistive microcantilever. Over the past few years, an increasingly evident number of studies have been conducted on using the microcantilevers as transducers in biochemical-sensing systems. In principle, adsorption of biochemical species on a functionalized surface of a micro-cantilever will cause bio-induced surface stress and accordingly the cantilever bends. We used this technique in the immunoassay. A microcantilever based biosensor with piezoresistive has been developed using surface micromachining technique in this paper, which is cost effective, miniaturized and high applicability. This provides a novel method to detect bio-molecules which is due to molecule binding induced cantilever deflection. We have demonstration of wireless real-time label-free detection of bio-linker and anti-CRP antibody, the signal was successfully detected by using piezoresistive cantilever biosensor. The tendency of cantilever deflection is agreement with optical-based cantilever detection. In the future, the piezoresistive cantilever biosensor will offer a powerful plateform for high-throughput bioassays in proteomics and immunology.
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Lin, Chih-Chang, and 林志昌. "Real-time detection of Nitric Oxide and Label-free protein biosensor." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/71964322661497231035.
Full textAbstract:
碩士國立交通大學
電子物理系所
97
In the past, it is complex and expensive to detect NO and protein. This work develops a real-time and label-free biosensor for nitric oxide (NO) and protein. Two sections will be included： The first section describes a real-time NO electrical sensor. In2O3 is functionalized with 3,4-Diaminobenzoic acid as chemical probe for detecting NO. S-Nitroso-N-acetylpenicillamine is used as NO donor. The readout current from a two-terminal In2O3 device varies with NO in the environment. The second section describes a real-time and label-free protein optical sensor. Porous ZnO is functionalized with Biotin and fluorescent molecules (BPDM-COOH-Zn, ZnC2). Since the affinity of Avidin to Biotin is strong, once Avidin binds with Biotin, Avidin will physically compress the fluorescent molecule and results in photoluminescence decrease. The change of photoluminescence provides the Avidin concentration in the environment.
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Chen, Wei-Chuan, and 陳韋全. "Signal Acquisition and Analysis of Real-Time Monitor System of Miniaturized Biosensor." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/02041222711504146301.
Full textAbstract:
碩士國立雲林科技大學
光學電子工程研究所
97
The sensor is a kind of device about electrochemical science, and its applications include clinical and environmental analyses, physiology, process control, etc. Therefore, how to accurately detect the sensor signal is one of the most important procedures for relative applications. In this study, a multi-electrode measurement system was prepared for potentiametric sensor to proceed with dynamic measurement and real-time display. This system will be classified with two parts, which are the fabrication of electrode and embodiment of the measurement system. However, the fabrication methods of electrode are provided and presented as two species of structures: one is the non-flexible electrode, and the other is flexible electrode. The embodied methods are to deposit the sensing membrane onto the different substrates using the R.F. sputtering system, and package using handmade process for non-flexible electrode or screen-printing technique for flexible electrode. Additionally, the measured information will be automatically stored as the measurement record and graph files for surveying afterward to analyze the characteristics of sensor by the appended functions. Nevertheless, this designed virtual instrument is used to detect signal whether the measurement system is suitable to be applied. The feasibility of designed system will be compared and analyzed. Therefore, the measurement of the electrode will be proceeded with its characteristic analysis such as sensitivity, linearity, stability, etc.
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Jou, Li-John, and 周立強. "Asiatic clam (Corbicula fluminea)–based dynamic biosensor for real-time in situ monitoring waterborne metals." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/54804785186442630757.
Full textAbstract:
博士國立臺灣大學
生物環境系統工程學研究所
95
The goal of this dissertation is to develop a novel freshwater clam Corbicula fluminea-based on-line bimonitoring system as a bioassay tool to offer a real-time and cost-effective method to measure copper (Cu) and cadminm (Cd) concentrations in natural water resources. The proposed system used sublethal changes in the daily valve closing activites of C. fluminea as a biological endpoint and built upon the basic principles of biological early warning system (BEWS) model in three phases. In the first phase, a probabilistic-based approach describing the valve closure behavior of C. fluminea in response to Cu and Cd was developed. The valve closure response data from published literature was reanalyzed to reconstruct the response time-dependent dose-response profiles based on an empirical three-parameter Hill equation model. The reconstructed dose-response profiles and EC50-time relationships associated with the fitted daily valve opening/closing rhythm characterized by a three-parameter lognormal function were integrated to successfully predict the time-varying bivalve closure rhythm in response to waterborne Cu/Cd. A probabilistic-based methodology associated with the time-varying dose-response relationships of valve closing behavior is incorporated into the mechanisms of a dynamic clam compiled by a LabVIEW graphic control program language in a personal computer (PC). It allows the parsimony estimation of the time-varying waterborne Cu/Cd concentrations for on-line providing the performances of the toxicity detection technique. Secondly, the biotic ligand model (BLM) describing the bioavailability was employed to link between acute Cu toxicity and its effect on valve closure behavior of freshwater clam C. fluminea based on the published experimental data of C. fluminea closure daily rhythm and dose-response profiles. The results show that a BLM-based Hill model best describes the free Cu2+-activity−valve closure response relationships. The proposed Cu-BLM-Corbicula model shows that the free ionic form of waterborne Cu bind specifically to a biotic ligand (i.e., clam gills) and impair normal valve closure behavior, indicating that a fixed-level of metal accumulation at a biotic ligand is required to elicit specific biological effects. The site-specific EC50(t) and valve closure rhythm at any integrated time was demonstrated to obtain a good prediction, indicating that the proposed model has the potential to develop a biomonitoring system as a bioassay tool to on-line measure waterborne Cu levels in aquatic systems. In the third phase, the principles of water chemistry were integrated into the modified BLM-based pH-specific concentration-time-response model. Through the combination of the Hill model-based dose-time-response function and the fitted daily rhythm function of valve closure, the constructed Cu-BLM-Corbicula-based programmatic mechanism can be used to simulate the valve closure rhythm exposed to copper in various time-varying scenarios. The compensatory mechanism under temperature-specific and pH-specific aquatic environmental conditions was incorporated into the constructed Cu-BLM-Corbicula model-based dynamic Cu detection mechanism to precisely and completely reflect the suitability for practical environmental statuses. The performance for a system testing in a dynamic clam synthesis was also demonstrated by employing a LabVIEW software in a PC. The simulation results reveal that the developed Cu-BLM-Corbicula-based programmatic mechanism can be used to indirectly estimate the time-varying waterborne Cu ion activity under the influence of water temperature and pH to further evaluate the local-specific waterborne Cu concentration. In the present study, an important system function for adjusting the time response and threshold concentration was added to improve the real-time metal toxicity detection technique. The virtual instrumentation techniques to design and simulate a C. fluminea-based biomonitoring system based on a valvometric conversion technique were adopted to greatly reduce the costs, development time and errors in implementing procedures. This proposed Cu-BLM-Corbicula model-based dynamic clam synthesis has been completed to provide a better understanding to quantify on-line measurement of Cu toxic effect on bivalve health to technically assist in developing a defensible site-specific BEWS for the protection of aquatic ecosystems, and may foster applications in clam farm management strategies.
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Tsai, Hsiao-chung, and 蔡曉忠. "Optimization of Acetylcholinesterase based on Fiber-Optic Biosensor for Real-Time Monitoring of Organophosphorus Pesticides." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/02492711709550683843.
Full textAbstract:
碩士國立清華大學
原子科學系
87
Organophosphorus pesticides (OPPs) are widely used as insecticides for agricultural or household purposes since 1970s. Although they can be quickly decomposed in the environment, their highly acute toxicity to acetylcholinesterase (AChE) received highly attention. Therefore, the development of high efficient analytical techniques for real-time monitoring the residues of OPPs in the environments is needed. The purpose of this study is to apply the sol-gel immobilization technology for developing a fiber-optic biosensor using AChE as biological recognition molecule for the detection of OPPs. Eight kinds of fluorescence dyes were used as the candidates for pH sensitive indicators. Also, the optimization in sol-gel formation and substrate preparation will be included. Results obtained in this study show that FITC-dextrans is a suitable pH sensitive fluorescence indicator for AChE based biosensor due to its low leaching ability in continuos system. The optimized ratio of TMOS:HCl:H2O was 1:3.6’10-5:2. The mixing ratio of enzyme-dye solution and sol solution was in the range of 3 to 5. By using 5mM pH8.9 Tris-HCl as immobilization buffer, a higher initial fluorescent intensity was observed. The buffer capacity for substrate preparation was 1mM pH8.5 Tris-HCl and the substrate concentration must below 50mM to get a stable pH value. Moreover, this homemade fiber-optic biosensor was highly stable in analyzing the acetylcholine with the relative standard deviation (RSD) of 3.5% (n=8). A good linearity of acetylcholine in the range from 0.5 to 20mM was also obtained (R2=0.98). A 30% inhibition can be achieved when 152ppb paraoxon was added into the system. This suggests the developed biosensor system is suitable for real-time analysis of organophosphorus pesticides.
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Jou, Li-John. "Asiatic clam (Corbicula fluminea)-based dynamic biosensor for real-time in situ monitoring waterborne metals." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2107200704540800.
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Alom, Azharul, and Azharul Alom. "Real-time detection of viruses by portable surface plasmon resonance biosensor with multi-metallic sensor chip." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/31630349587230457534.
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夏德玲. "Real-Time and Label-Free Detection of the Biomolecules with a Novel Side-Gated SiNW-FET Biosensor." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/51525371737386377340.
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碩士國立交通大學
奈米科技研究所
96
It is an important and developing capable issue to combine the semiconductor sensor devices with biomolecules for the future application of disease diagnosis. In the present work, the BRAFV599E mutation gene and cancer marker α-fetoprotein, which have been recently reported to restrict to the papillary thyroid carcinomas (PTCs) and liver cancer, respectively, were chosen as the target biomolecules. The devices based on semiconductor nanowires exhibit high sensitive and selective characteristics for the real-time, label-free, and excellent specificity detection of biomolecules and chemical species. A novel side-gate silicon nanowire field effect transistor (SiNW-FET) is fabricated by using the complementary metal oxide semiconductor (CMOS) FET compatible technology. The shrank nanowires with higher surface-to-volume ratio and individual side-gate for integration are achieved by the LOCOS process. Because of the above advantages, the devices have potential to integrate with microfluidic system for bio-detection application. Therefore, the detection strategy for PTC and liver cancer has been investigated with our SiNW-FET integration with microfluidic system for real-time sensing by measuring thecharacteristics of electrical signals. The FT-IR, fluorescence microscopy and UV spectrophotometer are also examined to check out our efficiency of the SAM and appropriate experimental parameters for bio-sensing. In the conclusion, the width of shrank nanowire by LOCOS process can be thinner than 100 nm. The drain current versus gate voltage (ID-VG) characteristic of the SiNW-FET exhibits about five orders of magnitude of Ion/Ioff ratio, and the threshold voltage shifts positively after hybridization of 100fM concentrations of BRAFV599E mutation gene and 3ng/mL concentrations of the cancer marker, α-fetoprotein, respectively. The results show that the side-gate nanowire device has the capability of acting as a real-time, label-free, highly sensitive and excellent selectivity SiNW-FET biosensor for important biomolecules. In addition, our approach offers a highly potential possibility to integrate with microfluidic-channel system for future parallel real-time detection of multiple chemical and biological species with controlling the individual side-gate in a single integrated chip.
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Nandakumar, Vijay. "Real-time monitoring and quantification of drug induced changes in endothelial cytoskeleton filaments using a cellular impedance biosensor." 2005. http://etd.utk.edu/2005/NandakumarVijay.pdf.
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Thesis (M.S.) -- University of Tennessee, Knoxville, 2005.Title from title page screen (viewed on Oct. 11, 2005). Thesis advisor: Anthony English. Document formatted into pages (xii, 124 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 70-74).
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Lai, Wen-Tsan, and 賴文燦. "Poly crystalline silicon nanowire field effect transistor based biosensor for highly sensitive, label-free and real-time detection of enterovirus DNA." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/92173365812167395162.
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碩士國立交通大學
生物科技學系
98
Enterovirus 71 (EV 71) is an important pathogen that causes higher morbidity and mortality in children around the world than those of other non-Polio enteroviruses. Its infection is neurotropic and even followed by rapid deterioration within average 3 days. The standard clinical methods for EV 71 identification require virus isolation in cell culture and reverse transcriptase polymerase chain reactions (RT-PCR). Virus isolation requires 5-10 days and hinders the subsequent treatment and disease control. Poly silicon nanowire field effect transistor has been shown to function as transducer for high sensitive, label-free and real-time biosensing to detect enterovirus infection. The selectivity of target for detection can be achieved by surface modification on NWFET. In our research, specific antibody or DNA sequences that recognize capsid protein or nucleic acid will be immobilized on poly Si NWFET. Currently, we are able to distinguish between EV 71 and CA 16 DNAs by real-time electrical analysis. It will be a promising biosensor for rapid diagnosis of EV 71 or other epidemic diseases.
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Chen, Jie-Ting, and 陳玠廷. "Design and Analysis of Flexible Screen-Printed Arrayed Glucose Biosensor Based on Multifunction Real-Time Remote Home Care in Wireless Sensing System." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/62050474617467732601.
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碩士國立雲林科技大學
電子與光電工程研究所碩士班
102
In this thesis, the wireless sensor network (WSN) with Zigbee technique is integrated with the glucose biosensor. The wireless sensing system is accomplished by the graphical language laboratory virtual instrumentation engineering workbench (LabVIEW). The wireless sensing system can be classified into two parts, which are the glucose detection system of front end and transmission platform of back end. The glucose detection system embraces ruthenium dioxide polyethylene terephthalate (RuO2/PET) biosensor, silver/silver chloride (Ag/AgCl) reference electrode and readout circuit device. The transmission platform is transmitted the detection signals in real-time, which displays the measurement results in the computer. In addition, the wireless sensing system is used to detect pH value in different buffer solutions and glucose value in different concentrations of glucose solutions. The Nafion is applied as immobilization material due to it has high chemical stability and the best biocompatibility. The enzyme composite solution is dropped on the RuO2 film as a glucose biosensor. We provide a real-time monitoring and rapid detection wireless sensing system. The range of pH values from pH 1 to pH 13 has good average sensitivity 51.38 mV/pH and linearity 0.995. The range of glucose solution concentration from 100 mg/dL to 500 mg/dL has good average sensitivity 0.179 mV(mg/dL)-1 and linearity 0.999 of the glucose biosensor.
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Huang, Yu-Wen, and 黃郁雯. "Real-Time and Label-Free Detection of the Prostate-Specific Antigen in Human Serum by a Novel Poly-silicon Nanowire-FET Biosensor." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/22348857927525452434.
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碩士國立交通大學
材料科學與工程學系奈米科技碩博士班
100
The application for disease diagnosis and recurrence prevention of high-sensitive field-effect transistor devices in detecting the biomolecules is a novel and developing technology. In this research, we used poly-silicon nanowire field-effect transistor (poly-Si NWFET) as biosensor which was fabricated by employing the sidewall spacer technique instead of expensive E-beam lithography method. The sidewall spacer technique has the advantages of simplicity and low-cost, comparing to the current commercial semiconductor process. By using these novel devices which exhibited characteristics of real-time, label-free and ultrahigh-sensitive, we could detect prostate-specific antigen (PSA) in human serum in this thesis. We firstly modified 3-aminopropyltriethoxysilane (APTES) on the silicon oxide surface followed by glutaraldehyde functionalized, and the PSA antibodies were immobilized on the aldehyde terminal. While PSA were prepared in the buffers maintaining appropriate pH values and ionic strength, the results indicated that the sensor could detect trace PSA which was down to 5 fg/mL in a micro-fluidic channel. Since serum proteome is very complex containing high levels of salts and other interfering compounds, we hereby developed a standard operating procedure for real sample pretreatment to keep a proper pH and ionic strength of the desalted serum, and also utilized Tween 20 serving as the passivation agent by surface modification on the nanowire to reduce non-specific binding for medical diagnostic applications. The novel poly-silicon nanowire field-effect transistor as diagnostic platform for monitoring cancer therapy and predicting the risk of early biochemical relapse is potential and developed in the future.
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YAN, SIAO-JIE, and 嚴孝傑. "The Analysis of the Stability, Interference, and Impedance for Magnetic Beads and Graphene Modified in Arrayed Flexible Nickel Oxide Glucose and Lactate Biosensor Based on Microfluidic Framework and the Measurement of Real-Time Sensing System." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/694838.
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碩士國立雲林科技大學
電子工程系
105
In this thesis, nickel oxide (NiO) was applied to a flexible arrayed pH sensor, and its sensitivity could be enhanced by changing oxygen content of sputtering gas. The optimal NiO film was applied to a flexible arrayed lactate biosensor and a flexible arrayed glucose biosensor. After that, lactate dehydrogenase (LDH) and glucose oxidase (GOD) were immobilized on the NiO film of above structure to fabricate the flexible arrayed lactate biosensor and flexible arrayed glucose biosensor, respectively. We used graphene oxide (GO) and magnetic beads (MBs) to modify the sensing film, which could enhance the ability of enzyme adsorption and the characteristics of the biosensors. Moreover, the electrochemical impedance spectroscopy was used to analyze the electrochemical impedance and confirm whether GO and MB did successfully modify the sensing film. Subsequently, it was investigated the response time, decay rate, interference effect and detection limit of the lactate and glucose biosensors based on NiO film modified by GO and MBs, respectively. In addition, the lactate and glucose biosensors based on NiO film modified by GO and MBs were integrated in the microfluidic framework, which sensing characteristics were respectively researched under different flow rates. Finally, the lactate and glucose biosensors based on NiO film modified by GO and MBs were combined in the wireless real-time sensing system based on XBee module to realize remote monitoring.
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CHEN, JIAN-SYUN, and 陳建勳. "The Research of Integrating the Differential Reference Electrode as well as Magnetic Beads and Graphene Modified in Arrayed Flexible IGZO Glucose Biosensor Based on Microfluidic Framework and the Fabrication of Multifunctional Enzyme Real-Time Sensing System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/wke9x5.
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碩士國立雲林科技大學
電子工程系
104
In this thesis, it was mentioned the enzymatic glucose biosensor was manufactured by using radio frequency sputtering system, thermal evaporation system and screen-printed technology, whose glucose sensing membrane was composed of indium gallium zinc oxide (IGZO) membrane and glucose oxidase (GOx). For enhancing sensing characteristics of enzymatic glucose biosensor, the sensing membrane was modified by graphene oxide (GO) and magnetic beads (MBs) to improve adsorption of enzyme and sensing characteristics. According to experiential results, the average sensitivity and linearity of enzymatic glucose biosensor modified by GO and MBs were 10.391 mV/mM and 0.998, respectively. To demonstrate that sensing membrane was successfully modified by GO and MBs, the electrochemical impedance spectroscopy (EIS) was used to analyze the capability of electron transfer for sensing membranes. The stability, lifetime, interference and detection limit of the enzymatic glucose biosensor modified by GO and MBs were investigated. Finally, the enzymatic glucose biosensor modified by GO and MBs was integrated with the microfluidic framework and the sensing characteristics under dynamic conditions, i.e., solution under flowing condition, were investigated. According to experiential results, under dynamic conditions, the average sensitivity and linearity of enzymatic glucose biosensor modified by GO and MBs were enhanced to 12.383 mV/mM and 0.999, respectively. Furthermore, in order to develop the real-time sensing system applied in measurement of pH value and multifunctional enzyme, the pH sensor as well as enzymatic glucose, lactate and urea biosensor modified by GO and MBs was combined with wireless sensing system to carry out the wireless sensing measurements, and this system complied with ZigBee wireless networking protocol which consisted of the XBee module, Arduino Mega 2560, readout circuit, biosensor and computer was employed to transmit the measurement signals. According to the experimental results, the average sensitivities of the pH sensor as well as enzymatic glucose, lactate and urea biosensor modified by GO and MBs were 50.059 mV/pH, 10.257 mV/mM, 55.747 mV/mM and 2.066 mV/(mg/dl), respectively.
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WU, CIAN-YI, and 吳芊嬑. "Investigation on Sensing Characteristics and Stability of Arrayed Flexible Glucose and Urea Biosensor Based on TiO2 and NiO Films Modified by Magnetic Beads and Graphene Oxide, and Integrated with Microfluidic Framework and Real-Time Sensing System." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3v4kj4.
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碩士國立雲林科技大學
電子工程系
106
In this thesis, two kinds of metal oxide were proposed as martrix for flexible arrayed urea biosensor. The metal oxide films were Nickel Oxide (NiO) and Titanium dioxide (TiO2), respectively. The radio frequency sputtering system deposits the sensing film, and the screen printing technology were used to prepare the conductive arrayed wires and the reference electrode, and the epoxy is to encapsulate flexible arrayed urea biosensor. However, the covalent binding method is used to immobilize the enzyme between the matrix of the urea biosensor, and the preparation of the urea biosensors were completed. Afterwards, the sensing films of nickel oxide and titanium dioxide were modified by using graphene oxide and magnetic beads to improve its properties. The basically sensing properties of the two kinds of matrix biosensors were measured, and response time, interference and detection limit were also measured. However, the urea biosenosrs were integrated into the microfluidic measurement system and wireless real-time sensing system to measure the sensing properties of the urea biosensor under dynamic conditions, and it achieved remote monitoring. In addition, the feasibility of TiO2 matrix for the development of glucose sensors were discussed. Finally, we compared the literatures with the urea biosensors and glucose sensor in this thesis.
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Wu, You-Xiang, and 吳友祥. "The Research of Differential Reference Electrode Integrated with Magnetic Beads and Graphene Oxide Modified Arrayed Flexible IGZO/Al Ascorbic Acid Biosensor Based on Microfluidic Framework as well as Measurements for Sensing Characteristics, Equivalent Circuit and Real-time Sensing System." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ktdemv.
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碩士國立雲林科技大學
電子工程系
106
In this thesis, the screen-printed technology, radio frequency sputtering system and thermal evaporation system were used to integrate indium gallium zinc oxide (IGZO) membrane, Al electrode and silver paste onto the PET (polyethylene terephthalate) substrate. Next, the covalent bonding was used to immobilize ascorbate oxidase (AOX) onto the IGZO sensing membrane, and the flexible arrayed enzymatic L-ascorbic acid (L-AA) biosensor was completed. Besides, the graphene oxide (GO) and magnetic beads (MBs) were used to modify IGZO sensing membrane, and the electrochemical impedance spectroscopy (EIS) was used to confirm whether the GO and MBs were modified onto the sensing membrane successfully. According to the experimental results, the average sensitivity and linearity of MBs-AOX/GO/IGZO/Al L-AA biosensor were 78.9 mV/decade and 0.997, respectively. In this thesis, the response time, drift effect, hysteresis effect, anti-interfering effect and life time were investigated. Moreover, the sensing characteristic of L-AA biosensor which was integrated with microfluidic framework was detected under the different flow rates. Finally, in order to achieve remote monitoring, the L-AA biosensor was integrated with wireless real-time sensing system based on XBee module.