Application Of Nanomaterials In Biological Analysis And Layer-by-layer Assembled Multilayer Film Applied In Electrochemical Catalysis

In this work, Application of nanomaterials in biological analysis and layer-by-layer assembled multilayer film applied in electrochemical catalysis were studied. How to synthetize quantum dots (QDs) toward a more simple and green way is the oal of nano-researchers, what's more, the interdiscipline of nanotechnique and life science has caught great interests of scientists.In the first part, 3-Mercaptopropyl acid-capped quantum dots (QDs) synthesized in aqueous solution were coupled to avidin-sulforhodamine, also named avidin-Texas red (ATR), via electrostatic attraction. An intensity reduction in the fluorescence emission spectrum of QDs and an enhanced fluorescence intensity of the dye were observed on account of fluorescence resonance energy transfer from the QD donors to the dye acceptors. In addition, the fluorescence characteristics of the QD-ATR conjugates were strongly related to the quantity of ATR, pH value and ionic strength.In the second part, Bioconjugation of the mercaptopropyl acid modified CdTe nanoparticles synthesized in aqueous solution to the labeling of mouse-IgG, then with the interaction with IgG antibody labeled on Rhodamine, A FRET(Fluorescence Resonance Energy Transfer) progress was studied in this work. In this work, donor-acceptor complexes were formed based on antibody-antigen interactions. Immunoglobulin antigen (mouse-IgG) wasthis work. In this work, donor-acceptor complexes were formed based on antibody-antigen interactions. Immunoglobulin antigen (mouse-IgG) was effectively conjugated to mercaptopropyl acid modified CdTe quantum dot synthesized in aqueous solution via electrostatic interaction, while organic dyes- tetramethylrhodamine isothiocyanate (TRITC) were attached to the corresponding antibody (anti-mouse IgG). The mutual affinity of the antigen and antibody brought the CdTe quantum dot and TRITC close enough together to allow the resonance dipole-dipole coupling required for fluorescence resonance energy transfer to occur. The formation of immunocomplexes resulted in fluorescence resonance energy transfer from the CdTe quantum dot donors to the TRITC acceptors.And furthermore, ZrO2/Poly(Fc-COOH) multilayer films were fabricated by a layer-by-layer deposition of ZrO2 and Poly(Fc-COOH) based on the surface sol-gel technique. The deposition process of ZrO2/Poly(Fc-COOH) multilayer films was monitored by UV-vis spectroscopy and QCM measurement, which revealed that the fabrication of ZrO2/Poly(Fc-COOH) multilayer films is a continuous and homogeneous process. The cross-sectional SEM image gave a total thickness of 64 nm for the (ZrO2/Poly(Fc-COOH))*19 (here 19 refers to the number of deposition cycles) deposited on a Ag-coated QCM resonator, which corresponds to a thickness of 3.4nm for one bilayei.A cyclic voltammetric study revealed that the number of deposition cycles of the ZrO2/Poly(Fc-COOH) multilayer films has an effect on the cathodic/anodic peak currents between the film and the electrode surface. When the number of layers is less than 5(including 5), the peak currentsincrease with the increase of number of deposition cycles. But when the number of layers is more than 5, the peak currents decrease although the amount of ferrence increases. Furthermore, we found that the Zr02/Poly(Fc-COOH) multilayer films modified electrode exhibits excellent electrocatalytic behavior toward H2O2. Thus, it is possible to develop a kind of good H2O2 sensor based on this study.