Dissertations / Theses on the topic 'Affinity sensor'

Ochratoxin A is a contaminant in wine and known to be immunosuppressive and possibly carcinogenic. Therefore, the development of a rapid and sensitive method for field analysis is required for risk assessment and management. The work presented in this thesis reports the construction of a sensor platform capable of fulfilling these requirements. As a sensor platform, screen-printed thick film electrodes and microelectrodes on a silicone support were investigated for sensor development. As biological recognition elements, an antibody specifically binding ochratoxin A and a peptide receptor that was designed using computational modelling were examined. A disposable immunosensor for ochratoxin A was developed based on screen-printing technology. An indirect competitive immunoassay format was used on bare screen printed gold electrode (SPGE). The performance of this sensor was compared to carboxmethylated dextran (CMD) modified SPGE. Detection was performed by chronoamperometry monitoring the reaction of tetramethylbenzidine and hydrogen peroxide catalysed by horseradish peroxidase. The SPGE-based immunosensor achieved a detection limit of 100 ng L-1 and the CMD-modified SPGE immunosensor 10 ng L-1. The latter has been used for ochratoxin A determination in wine samples and was validated against standard HPLC and a commercial immunoassay test kit. Wine sample analysis involved the sample pre-treatment using immunoaffinity chromatography, electrochemical wine component characterisation and interference control. The immunosensor format was transferred to a gold microelectrode array based on a silicone support for the purpose of signal sensitivity enhancement and miniaturisation in the prospect of field analysis. Preliminary data showed the characterisation of the microelectrode array immunosensor construction and characterisation. Further optimisation is needed to establish a calibration curve with the required sensitivity. The second part of the work comprised the design of a peptide receptor for ochratoxin A using computational methods by screening de novo designed peptide libraries. An octapeptide (CSIVEDGL) and a 13-peptide (GPAGIDGPAGIRC) were selected for synthesis and affinity characterised for ochratoxin A recognition using a surface plasmon resonance biosensor (BiacoreTM). The peptide receptors showed good sensitivity for ochratoxin A of 10 μg L-1. Preliminary affinity characterisation resulted in KA = 63 mM-1 for the 13-mer peptide and KA = 84 mM-1 for the octapeptide, which appears to be binding with higher strength to ochratoxin A. The affinity values correspond to the binding score (binding energy) calculated by computational modelling. This work shows the potential of designing peptide receptors for small molecules (e.g. ochratoxin A) and suggests their application in affinity sensors for detecting ochratoxin A contamination.

Much research has been done on aflatoxins since their discovery in the 1960’s where it was concluded that aflatoxins have carcinogenic, mutagenic, teratogenic and immunosuppressive properties. Aflatoxin M1 exists in milk and since milk is a major component of the diet of infants, the maximum permissible limit set by the EU is 50 parts per trillion (ng L -1 ). Current methods of analysis for aflatoxin M1 is primarily based around techniques such as HPLC and TLC which require extensively trained operators and equipped laboratories. Using antibodies as receptors in an enzyme linked immunosorbent assay (ELISA), the analysis costs can be reduced and simplified, however, an equipped laboratory is still required. Hence there is a need for a low cost, rapid, portable instrument which is easy to use at the point of source for the detection of aflatoxin M1. This thesis describes the development of affinity sensors to meet these requirements. Firstly the design and optimisation of an ELISA method was carried out, utilising a commercially sourced monoclonal antibody. Once the antibodies suitability for sensing aflatoxin M1 was determined the antibody was successfully employed as the receptor for a screen printed HRP/TMB based immunosensor. Upon the analysis of milk it was observed that milk caused extensive interference and through a series of chemical extractions the interference was attributed to whey proteins in the milk with suspicion towards a- lactalbumin. A simple pre-treatment technique of adding calcium chloride was performed and the interference from the whey proteins was removed. The resulting immunosensor achieved a sensitivity of 39 ng L -1 (Figure 3.26), however, poor reproducibility was observed due to the screen printed electrode production (%CV = 21% variance for screen printed electrode production). Gold cell on a chip microelectrode arrays were used to replace the screen printed electrodes and the successful covalent attachment of the antibody to the microelectrode array through PDITC cross linking compound was monitored using atomic force microscopy and scanning electron microscopy. It was shown that the majority of the antibodies during immobilisation orientate in a ‘side on’ orientation and therefore a cheap capture polyclonal antibody was first immobilised before the addition of the sensing anti-aflatoxin M1 monoclonal antibody. Using the microelectrode array an improvement of the sensitivity as well as a reduction of the milk interference was shown. Sensitivity was improved to 8 ng L -1 in milk (Figure 4.23). Further work was performed to substitute the fragile antibody used in the sensing layer for a robust synthetic peptide receptor. Initially a virtual library of synthetic peptides was created using de novo design techniques in silico. Further computational techniques were performed to determine the best peptide from the library. This peptide had a sequence of PVGPRP. From literature a peptide (LLAR) was reported with affinity for aflatoxin B1. This sequence along with the de novo design peptide was synthesised and tested using a host of techniques and immobilisation chemistries such as optical waveguide lightmode spectroscopy (OWLS), BIAcore and enzymatic techniques using EDC/NHS, glutaraldehyde and BS 3 cross linking methods. The affinity of both peptides to aflatoxin M1 was demonstrated however further work is required to quantify the affinity and to incorporate the peptides into the microelectrode array.

Les capteurs électrochimiques sont des outils pour la détection fiable, peu coûteux, avec une haute sensibilité et sélectivité, pour la détermination des composés biologiques et chimiques dans les domaines du diagnostic clinique, l'environnement et l'industrie alimentaire. Particulièrement, les Immunocapteurs, alliant une très grande spécificité. Également des nouveaux techniques produisent des résultats similaires, par exemple, les capteurs basés sur la technique des Polymères à empreinte moléculaire, la quelle produise des récepteurs artificiels. La technique devient très important dans les sciences bioanalytiques parce qu'il porte des avantages inhérents sur les récepteurs naturels: une grande stabilité dans des diffèrent environnement et conditions, également comptent avec une grande flexibilité dans la conception, une large gamme de molécules peuvent être utilisées. L'objectif du travail présenté ici est de développer des capteurs électrochimiques avec une très grande affinité et spécificité pour une analyte. Les quelles comprennent des applications très divers comme dans la protection de l'environnement, la sécurité alimentaire et le domaine biomédical. La première partie de la thèse présent l'état actuel de la conception et techniques de fabrication des biocapteurs. Ensuite, les aspects généraux des immuno capteurs électrochimiques et capteurs base sur des aptamères sont présentés ici, ainsi que plusieurs exemples rapportés dans la littérature pour la détection de marqueurs biologiques du cancer. Les avantages de l'intégration nanomatériaux dans les dispositifs de détection sont présentés. Ensuite, plusieurs aspects sur la technique des Polymères à empreinte moléculaire sont introduits. La partie personnelle de contribution est structuré en trois chapitres: en premier temps la méthodologie et les résultats obtenus pour le développement de deux essais biologiques pour la détection du marqueur tumoral Mucinl. Le premier chapitre est dédié sur un capteur à base de billes magnétiques, dans le deuxième chapitre une capteur aptamère base sur des nanoparticules d'or sans aucun marquage et finalement un capteur basée sur la technique des Polymères à empreinte moléculaire, cette protocole a été appliqué pour la détection d'explosifs, des médicaments, des hormones et les pesticides
Electrochemical sensors provide reliable and inexpensive tools for the determination of biological and chemical compounds with high sensitivity and selectivity, in the fields of clinical diagnosis, environment protection and food industry. Immunosensors hold particular promise, combining the high specificity of immuno- reactions with the sensitivity of electrochemical methods. Artificial receptors based on molecularly imprinted technique attracted considerable attention in bioanalytical sciences due to inherent advantages over natural receptors, such as high stability in harsh conditions and freedom of molecular design towards a wide range of molecules. The aim of the thesis presented here was to develop electrochemical affinity sensors based on various recognition receptors for environment monitoring, food safety and biomedical field. The first part of the thesis reviews the current state of knowledge in these fields. General aspects of electrochemical immuno- and apta-sensors are presented herein, together with several examples reported in the literature for the detection of cancer biomarkers. The advantages of integrating nanomaterials in sensing devices are then presented. At last, several aspects of the molecularly imprinted polymers are introduced. The personal contribution part is structured in three chapters, that include the methodology and results obtained for the development of biosensors for the detection of Mucinl tumor marker, the first chapter being focused on bioassays based on magnetic beads and second chapter on a label-free aptasensor based on gold nanoparticles, and finally, a third chapter dedicated to the molecularly imprinted-based sensors for the detection of explosives, drugs, hormones and pesticides

Optical sensor systems that integrate Long-Period-Gratings (LPG) as the detection arm have been proven to be highly sensitive and reliable in many applications. With increasing public recognition of threats from bacteria-induced diseases and their potential outbreak among densely populated communities, an intrinsic, low-cost biosensor device that can perform quick and precise identification of the infection type is in high demand to respond to such challenging situations and control the damage those diseases could possibly cause. This dissertation describes the development of a biosensor platform that utilizes polymer thin films, known as ionic self-assembled multilayer (ISAM) films, to be the sensitivity- enhancing medium between an LPG fiber and specific, recognition layer. With the aid of cross- linking reactions, monoclonal antibodies (IgG) or DNA probes are immobilized onto the surface of the ISAM-coated fiber, which form the core component of the biosensor. By immersing such biosensor fiber into a sample suspension, the immobilized antibody molecules will bind the specific antigen and capture the target cells or cell fragments onto the surface of the fiber sensor, resulting in increasing the average thickness of the fiber cladding and changing the refractive index of the cladding. This change occurring at the surface of the fiber results in a decrease of optical power emerging from the LPG section of the fiber. By comparing the transmitted optical power before and after applying the sample suspension, we are able to determine whether or not certain bacterial species have attached to the surface of the fiber, and as a consequence, we are able to determine whether or not the solution contains the targeted bacteria. This platform has the potential for detection of a wide range of bacteria types. In our study, we have primarily investigated the sensitivity and specificity of the biosensor to methicillin- resistant Staphlococcus aureus (MRSA). The data we obtained have shown a sensitive threshold at as low as 102 cfu/ml with pure culture samples. A typical MRSA antibody-based biosensor assay with MRSA sample at this concentration has shown optical power reduction of 21.78%. In a detailed study involving twenty-six bacterial strains possessing the PBP2a protein that enables antibiotic resistance and sixteen strains that do not, the biosensor system was able to correctly identify every sample in pure culture samples at concentration of 104 cfu/ml. Further studies have also been conducted on infected mouse tissues and clinical swab samples from human ears, noses, and skin, and in each case, the system was in full agreement with the results of standard culture tests. However, the system is not yet able to correctly distinguish MRSA and non-MRSA infections in clinical swab samples taken from infected patient wounds. It is proposed that nonspecific binding due to insufficient blocking methods is the key issue. Other bacterial strains, such as Brucella and Francisella tularensis have also been studied using a similar biosensor platform with DNA probes and antibodies, respectively, and the outcomes are also promising. The Brucella DNA biosensor is able to reflect the existence of 3 Brucella strains at 100 cfu/ml with an average of 12.2% signal reduction, while negative control samples at 106cfu/ml generate an average signal reduction of -2.1%. Similarly, the F. tularensis antibodies biosensor has shown a 25.6% signal reduction to LVS strain samples at 100 cfu/ml, while for negative control samples at the same concentration, it only produces a signal reduction of 0.05%. In general, this biosensor platform has demonstrated the potential of detecting a wide range of bacteria in a rapid and relatively inexpensive manner.
Ph. D.

Les filtres UV font partie des contaminants émergents portant un risque pour les environnements aquatiques. La quantification de ces molécules utilise généralement des techniques chromatographiques. Une méthode utilisant la spectroélectrochimie a été développée, celle-ci se base sur l’utilisation combinée d’une méthode électrochimique, la chronoampérométrie et la spectrophotométrie UV. Suite à l’application d’un potentiel oxydant, certains filtres UV voient leur spectre d’absorption modifié. La méthode développée permet l’enregistrement des spectres d’absorption UV de la solution étudiée avant et après application d’un potentiel, fixé à +1,8 V vs Ag durant 30 min. Un calcul de déconvolution utilisant le jeu de spectres obtenus permet l’identification et la quantification simultanée de quatre filtres UV. Cette méthode a été mise au point pour l’analyse d’avobenzone, d’octinoxate, d’octocrylène et d’oxybenzone. En plus de la mise au point de la méthode analytique, une campagne d’échantillonnage passif a été réalisée dans les eaux du littoral méditerranéen. Parmi les filtres UV étudiés, le bis-ethylhexyloxyphenol methoxyphenyl triazine, l’ethylhexyl triazone, l’octocrylène et le diethylamino hydroxybenzoyl hexyl benzoate ont été quantifiés à des concentrations de l’ordre du µg/L. Une étude de risque menée sur des organismes méditerranéen et tropicaux a montré l’existence d’un risque moyen à fort pour de nombreuses espèces
UV filters are part of the emerging contaminants causing a risk to aquatic environments. Quantification of those molecules usually uses chromatographic technics. A method based on spectroelectrochemistry was developed, it is based on the combined use of an electrochemical experiment, chronoamperometry, and UV spectrophotometry. Some UV filters’ spectrum are modified following oxidation. The developed method enable the recording of UV spectra before and after potential application, set at +1,8 V vs Ag during 30 min. Deconvolution using both spectra is then performed to simultaneously identify and quantify four UV filters. This method was developed for the analysis of avobenzone, octinoxate, octocrylene and oxybenzone. In addition to the analytical method, a passive sampling experiment was performed in Mediterranean waters. Among the studied UV filters, bis-ethylhexyloxyphenol methoxyphenyl triazine, ethylhexyl triazone, octocrylene and diethylamino hydroxybenzoyl hexyl benzoate were measured at concentration in the µg/L range. A risk assessment on Mediterranean and tropical species showed a medium to high risk for many species

In this work the development of affinity sensors for the detection of microcystin-LR based on a computationally designed artificial receptor is presented. Microcystin-LR is a cyclic heptapeptide hepatotoxin produced by Cyanobacteria (aquatic organisms also known as blue-green algae), which during blooms period can release toxins in water. Clinical signs of hepatotoxicosis have been observed in domestic animals and livestock and recently also in humans. At present, analysis of these toxins is achieved largely using conventional, time consuming and expensive techniques such as chromatographic methods (HPLC, TLC) and immunoassay. Therefore, the necessity of an easy and inexpensive method of analysis such a biosensor is becoming urgent. In this work an artificial receptor for microcystin-LR was synthesised using a combined approach of molecular imprinting and computer modelling. A computer-aided rational design was applied to study microcystin-LRlmonomers interactions in order to find an optimal composition for the synthesis of the receptor. The optimised composition, suggested by computer modelling, consisted in 1 mol of2-acrylamido-2-methyl-propanesulfonic acid and 6 mol ofurocanic acid ethyl ester for 1 mol of template. This monomer composition was then used to synthesise a molecularly imprinted polymer (MIP) and an enzyme- linked competitive assay was developed to characterise the computational receptor. In the assay, computational MIP was able both to detect 0.1 ~g rl of microcystin-LR and to distinguish the analyte among analogues such as microcystin-YR, microcystin-RR and nodularin. The computationally designed receptor was then used as a sensing element for the construction of sensor devices. A MIP-based piezoelectric sensor, capable of detecting 35 ~g rl of toxin in water, was developed. In order to improve the system sensitivity, the computational polymer was also used as a material in solid-phase extraction (SPE) for samples pre-concentration. The receptor was able to pre-concentrate up to 1,000 fold tap water samples spiked with only 1 J.1g rl of toxin. By combining MIP-based SPE and piezoelectric sensor an improved system with a minimum detectable concentration of toxin of 0.35 ~g rl was achieved. Encouraging preliminary results were also obtained in developing a MIP-based electrochemical sensor.

Le nitrate, source majeur d’azote pour la plupart des plantes,n’est pas seulement un élément nutritif mais est aussi une molécule signale. Il existe cependant des réponses au nitrate contrastées entre les différentes plantes supérieures. Chez Medicago truncatula, espèce modèle de la famille des légumineuses, le nitrate a un effet inhibiteur sur la croissance de la racine primaire en phase post-germinative. Une étude de génétique quantitative a montré qu’un transporteur de nitrate se situe au pic d’un QTL impliqué dans la croissance de la racine primaire. La caractérisation fonctionnelle de ce transporteur, nommé MtNRT1.3 et renommé MtNPF6.8, a montré que celui-ci est à double affinité pour le nitrate. Ce transporteur est alors susceptible de participer à l’influx de nitrate dans la plante. Après l’obtention de trois génotypes mutants RNAi stables, les expérimentations utilisant duK15NO3 ont montré que ce transporteur participe effectivement à l’influx de nitrate lié au système de transport à faible affinité inductible dans la plante (iLATS). En revanche,la mutation de MtNPF6.8 ne semble pas avoir de conséquence sur le métabolisme azoté. Par ailleurs, les études sur la croissance de la racine primaire ont permis de confirmer l’implication du transporteur sur ce caractère phénotypique. L’inhibition de croissance de la racine primaire observée sur nitrate chez le génotype sauvage est alors imputée, à l’échelle cellulaire, à une modulation de l'élongation cellulaire. La possibilité que l’ABA, hormone végétale, joue un rôle dans la médiation de cette réponse dépendant du nitrate, est fortement favorisée. L’ensemble de résultats, conforté par une étude de mutants exprimant ce transporteur chez A. thaliana, indique donc que MtNPF6.8 est un senseur de nitrate pour la plante en phase post germinative,ceci indépendamment de sa fonction de transport de nitrate
Nitrate, a major nitrogen source for most plants, is not only anutrient but also a signaling molecule. However, there arecontrasting responses to nitrate between different higherplants. In the model legume Medicago truncatula, nitrate hasan inhibitory effect on the primary root growth in postgerminationphase. A quantitative genetic study has shownthat a nitrate transporter is localized at the peak of a QTLinvolved in the primary root growth. Functionalcharacterization of the transporter, named MtNRT1.3 andrenamed MtNPF6.8, showed that it encodes a dual affinitynitrate transporter. MtNPF6.8 is likely to participate in thenitrate influx in the plant. After obtaining three knockdownlines by RNA interference, experiments using K15NO3 showedthat this transporter is effect involved in nitrate influx relatedto the inducible low affinity transport system (iLATS).However, mutation in MtNPF6.8 does not any effect onnitrogen metabolism. In addition, studies on the primary rootgrowth have confirmed the involvement of the transporteron phenotypic trait. In wild-type plants, cortical cell sizedecreased after nitrate treatment, showing that primary rootgrowth was due to this reduced cell elongation. Thepossibility that ABA also plays a role in mediating this nitratedependent response is heavily favored. All these results,reinforced by a study of mutants expressing this transporterin A. thaliana, indicate that MtNPF6.8 is a nitrate sensor forMedicago in the post-germination phase, independently ofits nitrate transport activity

Chow Ka-man.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (leaves 52-55).
Abstracts in English and Chinese.
Chapter 1 --- Introduction
Chapter 1.1 --- Chemical sensors --- p.1
Chapter 1.2 --- Quartz crystal microbalance --- p.4
Chapter 1.3 --- Concept of affinity mass sensor --- p.8
Chapter 1.4 --- Film immobilization technologies --- p.9
Chapter 1.5 --- Research outlines --- p.13
Chapter 2 --- Experimental
Chapter 2.1 --- Sensor fabrication --- p.14
Chapter 2.2 --- Flow-through cell --- p.16
Chapter 2.3 --- Analysis procedures --- p.19
Chapter 2.4 --- Response curve --- p.19
Chapter 2.5 --- Experimental setup --- p.21
Chapter 3 --- Detection of ascorbic acid by affinity mass sensor based on 3-aminophenylboronic acid
Chapter 3.1 --- Conventional analytical methods --- p.23
Chapter 3.2 --- Research method - affinity mass sensor based on APBA --- p.24
Chapter 3.3 --- To locate the binding site in ascorbic acid --- p.25
Chapter 3.3.1 --- Steric energy calculated by molecular modeling --- p.26
Chapter 3.4 --- Optimization of experimental variables --- p.29
Chapter 3.4.1 --- Effect of pH --- p.29
Chapter 3.4.2 --- Effect of sample volume --- p.30
Chapter 3.4.3 --- Effect of flow velocity --- p.30
Chapter 3.5 --- Calibration and Reproducibility --- p.32
Chapter 3.6 --- Kinetic analysis --- p.33
Chapter 3.7 --- Stability of sensor --- p.37
Chapter 3.8 --- Interference studies --- p.37
Chapter 3.9 --- Determination of ascorbic acid in real samples --- p.39
Chapter 3.9.1 --- Results and Discussion --- p.39
Chapter 3.10 --- Comparison with conventional ascorbic acid sensors --- p.42
Chapter 3.11 --- Summary --- p.42
Chapter 4 --- Boronic acid derivatives for the detection of sugars
Chapter 4.1 --- Scope of this work --- p.43
Chapter 4.2 --- Results and Discussion --- p.44
Chapter 4.3 --- Summary --- p.49
Conclusion --- p.50
References --- p.52
List for tables --- p.56
List for figures --- p.57
Appendix I --- p.59
Appendix II --- p.61

碩士
國立成功大學
奈米科技暨微系統工程研究所
97
Some specific proteins existing and correlating with disease in the blood or the food, its concentration changes or structural change, is considered as the symbol of disease development. On clinic, immunoassay is applied to detect these substances and measure the antibody or antigen concentrations owing to their high bio-specific recognition interaction with their complementary target. In fact, the drawback of immune analytical instrument which based on optical method not only is high price and complicated operation, but false negative detection is often occurred. Among this, the fail in eluting processes for cleaning away the unbonding substances to be the main reason can be considered. To promote this, a microfluidic immuno-chip which is made by micro electro-mechanical technology and combining two zones that are modified (1) a series of insulator-coated electrodes as electro-wetting on dielectric (EWOD) construction and (2) a antibody (IgG) - modified gold electrode. The former is designed for creating a droplet containing target sample and transporting it in chip by EWOD. By stepwise operating the electrodes rapidly to be hydrophilic and hydrophobic, the sample was moved to the sensing zone. The later is for detecting the concentration of target sample based on measuring the extent of impedance change. The self-assembly monolayer, 11-MUA, possessing a thiol group in one side will spontaneously bind onto gold electrode and a carboxylic group in the other side was activated by the agents of EDC/NHS that may promote the bind with antibody through its amino group. After the blocking treatment with bovine albumin serum, this zone will be used as for detecting Protein A. we also treated the intersection of zone 1 and 2 by oxygen plasma to allow the sensing zone to be more hydrophilic that will spontaneously achieve movement and promote the feasibility in sample transportation and electrode elution. Moreover, AC eletroosmosis flow (ACEOF) was introduced by setting the sensing electrode at 8 Vpp with 500 Hz before detection that will reduce the time for affinity reaction dawn to be 50 sec from 1 hr. As a result, the resistance change (ΔRet) by electro-chemical impedance spectroscopy for detecting protein A showed a linear correlation in the range of 1-50 ng/ml. The microfluidic system can be systemized for multiplex immuno-detection chip in the future.

Adenosine Triphosphate (ATP) can be released as a signal between cells in an autocrine and paracrine manner that binds purinergic receptors. Highly conserved, purinergic receptors expressed on the cell surface of neurons and astrocytes are capable of being activated across eight orders of magnitude from hundreds of nanomolar ATP to millimolar. Genetically encoded fluorescent protein biosensors have been used to detect ATP outside the cell, but a high affinity extracellular ATP sensor is required to study the ATP signaling dynamics from nanomolar to micromolar magnitudes. Previously, our lab developed a first generation sensor of extracellular ATP called ECATS1 (Conley et al.). To develop an improved sensor, we caried out site-directed mutagenesis of the sensor's ATP binding site and identified a mutant that exhibited a 4-fold increase in ATP binding affinity in solution. We then optimized the membrane-tethering of the sensor to achieve the 4-fold increase in extracellular ATP binding affinity when measured on live cell.s This second-generation sensor was dubbed ECATS2. As a proof-of-concept application, we sought to detect ATP release from cells using in vitro models of edema. We subjected HEK293A cells to hypo-osmotic shock (HOS), revealing ATP release at micromolar levels. Then we tested HOS in cultured cortical astrocytes, also revealing micromolar ATP release. However, when we tested neuron-astrocyte co-cultures, we no longer observed ATP release in response to HOS. Interestingly, this implies that co-culture either entirely prevented ATP release from astrocytes or dampened it into the nanomolar range below the limit of ECATS2 detection. Thus, we have validated the development of a higher affinity, second-generation sensor and used it to discover that ATP release from astrocytes after HOS can be affected by the presence of neurons.

by Lee Tin-wan.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.
Includes bibliographical references (leaves 79-84).
Abstracts in English and Chinese.
Chapter 1. --- Introduction
Chapter 1.1 --- Chemical sensors --- p.1
Chapter 1.2 --- Quartz crystal microbalance --- p.5
Chapter 1.3 --- Film immobilization technologies --- p.11
Chapter 1.4 --- Research Outlines --- p.13
Chapter 2. --- Saccharide detection by affinity mass sensor
Chapter 2.1 --- Concept of affinity mass sensor --- p.15
Chapter 2.1.1 --- Affinity chromatography --- p.15
Chapter 2.1.2 --- Basis of affinity mass sensor --- p.17
Chapter 2.1.3 --- Saccharide sensing --- p.19
Chapter 2.2 --- Experimental --- p.20
Chapter 2.2.1 --- Flow-through cell --- p.21
Chapter 2.2.2 --- QCA 917 quartz crystal analyzer --- p.21
Chapter 2.2.3 --- Experimental setup --- p.25
Chapter 2.2.4 --- Sensor fabrication --- p.29
Chapter 2.2.5 --- Analysis procedures --- p.29
Chapter 2.3 --- Results and Discussion --- p.30
Chapter 2.3.1 --- Formation of boronate complex --- p.30
Chapter 2.3.2 --- Response curve --- p.31
Chapter 2.3.3 --- Ligand (APBA) immobilization --- p.32
Chapter 2.3.4 --- Effect of various operating parameters --- p.35
Chapter 2.3.5 --- Calibration and reproducibility --- p.38
Chapter 2.3.6 --- Kinetics analysis --- p.39
Chapter 2.3.7 --- Stability of sensor --- p.44
Chapter 2.3.8 --- Determination of fructose in real samples --- p.44
Chapter 2.3.9 --- Comparison with conventional saccharides sensors --- p.46
Chapter 2.4 --- Summary --- p.47
Chapter 3. --- Sol-gel fabrication of affinity mass sensor
Chapter 3.1 --- Principle of sol-gel method --- p.48
Chapter 3.2 --- Encapsulation of organic molecules in sol-gel matrices --- p.51
Chapter 3.3 --- Experimental --- p.53
Chapter 3.3.1 --- Preparation of alkoxide solutions --- p.53
Chapter 3.3.2 --- Film deposition on QCM --- p.55
Chapter 3.3.3 --- Film characterization and surface analysis --- p.56
Chapter 3.4 --- Results and Discussion --- p.57
Chapter 3.4.1 --- Optimization of conditions for sol-gel process --- p.57
Chapter 3.4.1.1 --- Choice of catalyst --- p.57
Chapter 3.4.1.2 --- "H2O: TEOS ratio, R" --- p.59
Chapter 3.4.1.3 --- Ligand loading --- p.60
Chapter 3.4.1.4 --- Surface active agent --- p.60
Chapter 3.4.1.5 --- Temperature --- p.61
Chapter 3.4.1.6 --- Ageing and drying --- p.62
Chapter 3.4.2 --- Characterization of APBA encapsulated film --- p.62
Chapter 3.4.3 --- Performance of the sol-gel derived sensor --- p.65
Chapter 3.4.3.1 --- Calibration --- p.65
Chapter 3.4.3.2 --- Stability --- p.66
Chapter 3.4.3.3 --- Selectivity --- p.68
Chapter 3.4.4 --- Applicability of the sol-gel derived sensor --- p.69
Chapter 3.4.5 --- Comparison between sensors fabricated via crosslinking method and the sol-gel method --- p.70
Chapter 3.4.5.1 --- Surface uniformity --- p.70
Chapter 3.4.5.2 --- Reproducibility in mass deposition --- p.72
Chapter 3.4.5.3 --- Stability --- p.72
Chapter 3.4.5.4 --- Sensitivity towards fructose standard --- p.73
Chapter 3.4.5.5 --- Comparison of precision and accuracy --- p.73
Chapter 3.5 --- Summary --- p.75
Conclusion --- p.77
References --- p.79
Titles for tables --- p.85
Captions for figures --- p.86
Appendix I --- p.88
Appendix II --- p.89
Appendix III --- p.95

by Shao Bing.
Thesis (Ph.D.)--Chinese University of Hong Kong, 1997.
Includes bibliographical references (p. 111-122).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.

碩士
樹德科技大學
人類性學研究所
102
The paper reports the results of a study that examined the relationships among love schemas, affinity-seeking behaviors and reactions to a romantic break-up. We asked 553 participants to recall the affinity-seeking strategies employed to initiate a romantic relationship and reactions to a romantic break-up and compared those strategies to their self-reported love schemas. Consistent with previous studies, relationships among love schemas, affinity-seeking behaviors and reactions to a romantic break-up were found, indicating that male students and female students relied on somewhat different strategies for affinity-seeking behaviors and reactions to a romantic break-up. Love schemas were also found to be correlated with the coping strategies employed in affinity-seeking and reactions to a romantic break-up. Implications of these results suggest that love schemas were good indicators to predict the strategies for affinity-seeking behaviors and reactions to a romantic break-up, and could be useful reference to promote affective education in senior high school in Taiwan. Limitations of the study and avenues for future research were discussed.