Thesis (M.S.)--The Chinese University of Hong Kong. / Bibliography: leaves 103-110.

Thesis (Ph. D.)--Zürich Universität, 1907.

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 Ka Wai Wong. / "June 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / 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. / by Ka Wai Wong.

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.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Advances in pharmacology, biochemistry and biotechnology are increasingly dependant upon affinity chromatography as a preferred separation technique for the purification and characterisation of specific biomolecules. In the past few years avidin-biotin technology has been widely and successfully used in the fields of medicine, pharmacy, biology and biochemistry. The avidin-biotin complex (ABC) has been used as a mediator for affinity chromatography, affinity cytochemistry, immunoassay, histopathology, bioaffinity sensors, erosslinking and immobilisation studies. The main reason for the popularity of the ABC and its growing usefulness in biotechnology is the exceptionally high affinity (1015 M-l) and stability of the noncovalent interaction between avidin and biotin. The use of the ABC is broadening as different biotin derivatives and avidin-containing conjugates are becoming commercially available. The aim of this work was to evaluate the usefulness of a plutonic" FI 08 and the ABC conjugate to effect affinity separation. Towards this aim, the adsorption of plutonic" F108 onto hydrophobic polysulphone membrane surfaces was studied. This information was used to determine the theoretical maximum amount of pluronic" FI08 that will adsorb onto a unit surface area of the membrane. It is known that the polypropylene oxide (PPO) centre block ofthe pluronic" F I08 surfactant molecule governs the concentration of pluronic" F I 08 molecules that will adsorb onto a given hydrophobic surface. If the maximum coating concentration of plutonic" FI08 is known, one can assume that the maximum coating concentration of any pluronic derivative, with the same PPO centre block size, will be the same. Adsorption studies were carried out, the Langmuir adsorption isotherm was determined, and subsequently the fractional coating was calculated. The end-groups of plutonic" FI08 were modified as follows and the substituted pluronic was adsorbed onto a membrane that was to act as the solid support matrix in the development of an affinity system: Amino pluronic was synthesised by first tosylating pluronic" FI08, followed by azidation with NaN3 then reduction with LiAI~. The synthesised amino pluronic was then biotinylated using N-hydroxysuccinimide biotin ester. The suitability of this synthetic route was first assessed on a model compound, 2-methoxyethylamine, and validated by NMR (Nuclear Magnetic Resonance) spectroscopy. The synthetic protocol was then used to derivatise the larger pluronic molecule. The affinity system was tested on two different hydrophobic surfaces: polystyrene and polysulphone membranes (PSMs). Avidin-conjugated horseradish peroxidase was obtained and used to interact with the immobilised biotin. The enzymatic reaction of the coupled peroxidase converted the substrate, 2, 2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) to a coloured product. The colour developed is proportional to the amount of biotin that was immobilised on the hydrophobic surfaces studied. Non-covalent immobilisation of the synthesised biotin-pluronic molecule was successfully obtained onto the hydrophobic polystyrene as well as the polysulphone membrane surfaces. / AFRIKAANSE OPSOMMING: Vooruitgang in die farmakologie, biochemie en biotegnologie word al meer afhanklik van affiniteits chromatografie as die verkose tegniek vir die suiwering en karaterisering van spesifieke biomolekules. Oor die afgelope jare het die avidien-biotien tegnologie homself as baie bruikbaar bewys in die mediese, farmakologiese, biologiese en biochemiese velde. Toepassings waar die avidien-biotien kompleks betrokke was sluit in die toepassing as 'n mediator vir affiniteits chromatografie, affiniteits sitologie, immuno bepalings, histopatologie, bioaffiniteits sensors sowel as kruisbinding en immobiliserings studies en vele meer. Die hoofrede vir die gewildheid van die avidien-biotien kompleks en die groeiende bruikbaarheid in die biotegnologie is die buitengewone hoë affiniteit (l015 M-I ) en stabiliteit van die nie-kovalente interaksie tussen avidien en biotien. Die toepassingsveld van die avidien-biotien kompleks word wyer met die verskeidenheid biotien derivate en avidien-bevattende konjugate wat kommersiëel beskikbaar is. Die doel van die werk wat hier gedokumenteer word is om die bruikbaarheid van Plutonic" FI08 en die avidien-biotien kompleks, vir gebruik in 'n affiniteits chromatografie sisteem, te evalueer. Om hierdie doel te bereik is die adsorpsie van Pluronic" FI08 aan hidrofobiese polisulfoon membraan oppervlaktes bestudeer. Die eksperimentele data wat gegenireer is, is gebruik om die teoretiese maksimum hoeveelheid Pluronic wat per eenheids oppervlakte membraan adsorbeer te bepaal. Dit is reeds bekend dat die polipropileen (PPO) middel blok van die Pluronic emulgant die konsentrasie van die geadsorbeerde Pluronic molekules op 'n gegewe hidrofobiese oppervlakte bepaal. Indien die maksimum bedekkingskonsentrasie VIr maksimum oppervlakbedekking van Plutonic" FI08 bekend is, kan teoreties aanvaar word dat die bedekkingskonsentrasie vir enige Pluronic derivaat met dieselfde grootte PPO blok dieselfde sal wees. Adsorpsiestudies was uitgevoer om die Langmuir adsorpsie isoterm te bepaal. Daaropvolgend was die fraksionele bedekking bereken. Amino-pluronic was gesintetiseer deur die eindpunte van Pluronic te derivatiseer. Hierdie Pluronic derivaat was gevolglik geadsorbeer aan 'n membraan wat gedien het as die soliede oppervlakte vir die ontwikkeling van 'n affiniteits chromatografie sisteem. Amino-pluronic was gesintetiseer deur Pluronic eers te tosileer en daarna te asideer met NaN3 en laastens te reduseer met LiAI~. Die produk was gebiotinileer deur gebruik te maak van N-hidroksisuksinimied-biotien-ester. Die bruikbaarheid van hierdie sintetiese roete is eers bepaal deur van 'n model verbinding, 2-metoksiëtielamien, gebruik te maak en dit met behulp van KMR (Kern Magnetiese Resonans) spektroskopie te karakteriseer. Die affiniteits sisteem is getoets op twee verskillende hidrofobiese oppervlaktes naamlik polistireen en polisulfoon membraan oppervlaktes. Avidien gekonjugeerd met 'n peroksiedase ensiem is gebruik om met die geïmmobiliseerde biotien te assosieer. Die ensiematiese reaksie van die gekoppelde peroksiedase het die substraat 2, 2' -azino-di-(3-etiel-benzthiazolien-6-sulfoonsuur) (ABTS) omgesit na 'n gekleurde produk, waar dit teenwoordig is. 'n Reeks wasstappe is gebruik om die gemodifiseerde peroksidase ensiem wat nie aan die hidrofobiese oppervlakte gekoppel nie, weg te spoel. Hierdeur is die mate van binding aan die hirofobiese oppervlakte gekwantifiseer deur die kleur te kwantifiseer wat ontwikkelomdat die kleurontwikkeling direk proporsioneel is aan die hoeveelheid peroksidase wat nog aan die membraan gekoppel is. Nie-kovalente immobilisasie van die gesintetiseerde biotien-pluronic molekule is suksesvolop beide die hidrofobiese polistireen oppervlakte sowel as die polisulfoon membraan verkry.

Um biossensor de afinidade química baseado no fenômeno da reflexão total interna é apresentado. Nesse, as propriedades particulares apresentadas pelas componentes ortogonais de polarização do campo elétrico da luz permitem que ambas se cancelem na vizinhança do ângulo crítico da reflexão interna, proporcionando um meio para sua determinação unívoca, permitindo monitorar o mesmo como função do índice de refração de uma amostra de interesse. Um estudo acerca dos principais aspectos teóricos envolvidos no fenômeno da reflexão total interna foi realizado, a fim de explorar e justificar os fenômenos observados. A montagem experimental utilizada nos experimentos consiste de um laser de HeNe emitindo em 633 nm, um polarizador, uma lente semicilíndrica de alto índice de refração, produzida com um vidro denso do tipo flint, um filme produzido com um anticorpo, que é depositado sobre essa lente, um analisador paralelamente orientado com relação ao eixo de transmissão do polarizador, um dispositivo transdutor, que converte um sinal luminoso em sinais elétricos, uma solução aquosa do antígeno específico e de um computador, onde as informações coletadas pelo transdutor são tratadas por meio de um programa de aquisição de dados desenvolvido em uma plataforma gráfica de programação. O programa empregado permite o acompanhamento das variações do perfil luminoso, devido à interação do filme de anticorpos com a solução de antígenos, coletado pelo transdutor em tempo real, ou seja, é possível acompanhar toda evolução da reação química entre um par de espécies químicas em tempo real. Para confirmação da efetividade da técnica, foram comparadas medidas obtidas com um refratômetro comercial, onde foi constatado que o sistema possui sensibilidade suficiente para acompanhar mudanças da ordem de 10-5 unidades do índice de refração. / A chemical affinity biosensor based on the phenomenon of total internal reflection is presented. In it, the particular properties exhibited by the orthogonal polarization components of the electric field of light allow them to cancel in the vicinity of the critical angle of the internal reflection, providing means for its univocal determination, allowing its monitoring as a function of the refractive index of a sample of interest. A study about the theoretical aspects involved in the total internal reflection phenomenon was carried out in order to explore and justify the observed phenomena. The experimental set up consists of a HeNe laser emitting at 633 nm; a polarizer; a high refractive index semi-cylindrical lens, produced with a dense flint type glass; a film produced with an antibody, which is deposited over the aforementioned lens; an analyzer oriented parallel to the transmission axis of the polarizer; a transducer device, which converts a light signal into electric signals; an aqueous solution of the specific antigen and a computer, where the information collected by the transducer is treated with a data acquisition software developed in a graphical programming platform. The software allows one to monitor changes in the light profile due to interaction of the antibody with the antigen solution, collected by the transducer in real time, i.e. it’s possible to follow the evolution of the chemical reaction between a couple of chemical species in real time. To confirm the effectiveness of the technique a comparison with measurements obtained with a commercial refractometer was carried out, where it was verified enough sensitivity to follow changes of the order of 10-5 refractive index units.

In considering the concept of surface-immobilised liposomes as a drug release system, two factors need to addressed, the interfacial surface density of the liposomes for maximum drug loading and the stability of these liposomes to allow for controlled drug release. This thesis investigates a multilayer system for the affinity immobilisation of liposomes and their stability to various applied stresses. In the work presented here an allylamine monomer was used to create plasma coatings that were stable, thin and amine-rich. The aging studies using AFM showed these films to rapidly oxidise on exposure to water. The freshly deposited films were used for further surface modifications, by the covalent grafting of PEG layers of different interfacial densities under the conditions of varying polymer solvation. The AFM was used to measure the interaction forces between the grafted PEG layers and modified silica interfaces. It was found that the polydispersity of the PEG species resulted in bridging interactions of ???brush???-like PEG layers with the silica surface. These interactions were screened minimised by increasing the ionic strength of the solution. Although the densely grafted PEG layers were found to be highly protein-resistant by the XPS and QCM-D some minor protein-polymer adhesions were observed by the AFM. The densely anchored biotinylated PEG chains served as an optimum affinity platform for affinity-docking of NeutrAvidinTM molecules, which assembled in a rigid, 2-D layer as confirmed by the QCM-D. The submonolayer surface density of NeutrAvidin, as determined by Europium-labelling, was attributed to steric hindrance of the immobilised molecules. The final protein layer enabled specific binding of biotin-PEG-liposomes as a highly dissipative, dense and stable layer verified by tapping mode AFM and QCM-D. We found that these liposomes were also stable under a range of stresses induced by the shearing effects of water, silica probe and HSA layer at increased loads and velocities. The frictional response of the liposome layer also demonstrated the viscoelasticity and stability of these surface immobilised liposomes. Finally, the minimal adhesive interaction forces, as measured by the AFM, demonstrated the repellency of these liposomes to commonly found proteins, such as HSA.

In considering the concept of surface-immobilised liposomes as a drug release system, two factors need to addressed, the interfacial surface density of the liposomes for maximum drug loading and the stability of these liposomes to allow for controlled drug release. This thesis investigates a multilayer system for the affinity immobilisation of liposomes and their stability to various applied stresses. In the work presented here an allylamine monomer was used to create plasma coatings that were stable, thin and amine-rich. The aging studies using AFM showed these films to rapidly oxidise on exposure to water. The freshly deposited films were used for further surface modifications, by the covalent grafting of PEG layers of different interfacial densities under the conditions of varying polymer solvation. The AFM was used to measure the interaction forces between the grafted PEG layers and modified silica interfaces. It was found that the polydispersity of the PEG species resulted in bridging interactions of ???brush???-like PEG layers with the silica surface. These interactions were screened minimised by increasing the ionic strength of the solution. Although the densely grafted PEG layers were found to be highly protein-resistant by the XPS and QCM-D some minor protein-polymer adhesions were observed by the AFM. The densely anchored biotinylated PEG chains served as an optimum affinity platform for affinity-docking of NeutrAvidinTM molecules, which assembled in a rigid, 2-D layer as confirmed by the QCM-D. The submonolayer surface density of NeutrAvidin, as determined by Europium-labelling, was attributed to steric hindrance of the immobilised molecules. The final protein layer enabled specific binding of biotin-PEG-liposomes as a highly dissipative, dense and stable layer verified by tapping mode AFM and QCM-D. We found that these liposomes were also stable under a range of stresses induced by the shearing effects of water, silica probe and HSA layer at increased loads and velocities. The frictional response of the liposome layer also demonstrated the viscoelasticity and stability of these surface immobilised liposomes. Finally, the minimal adhesive interaction forces, as measured by the AFM, demonstrated the repellency of these liposomes to commonly found proteins, such as HSA.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 118-128).