Study On Optical Biosensor Method Based On Novel Nanoparticles

With the rapid development and in-depth study of the life sciences, biological molecules play an increasingly important role in biology, therefore it is important that establish a detection method which is fast, accurately, real-time detection and analysis of various types of biological molecules in the biomedical, clinical diagnosis and treatment, the environment monitoring and material science, etc. Nanomaterials has unique physical and chemical properties, it can improve the signal to noise ratio of chemical, biological sensor, the combination of the two can can build a series of new optical biosensor technology that has high sensitivity, high selectivity and simple operation and low cost using in the detection of biomolecules. This study used hydrothermal method and microwave-assisted hydrothermal method to synthesis copper sulfide nanorods, ceria nanopspheres and gold nanoclusters, based on these three nanomaterials, we have established new optical sensing method to detect hydrogen peroxide, melamine and creatinine. Specific contents are as follows:One-pot hydrothermal approach was used to synthesis copper sulfide (CuS) nanorods which exhibited intrinsic peroxidase-like activity and according to colorimetric detection of hydrogen peroxide. Under the conditions of the presence of H2O2, the substrate o-phenylenediamine (OPD) is catalytically oxidized OxOPD with the color change phenomenon of visually observable. In this case, use UV-visible spectrometry to achieve absorbance determination of oxidation products OxOPD and the quantitative detection of H2O2 with a linear range 1.0-1000.0 μmol L-1 and a detection limit of 1.1* 10 "7 mol I/1.CeO2 nanospheres were synthesized via microwave-assisted hydrothermal method, it showed good stability and dispersion in water, CeO2 nanospheres exhibited intrinsic peroxidase-like activity. After a certain amount of H2O2 with melamine occurred addition reaction, CeO2 nanospheres as the catalyst will catalyze the oxidation-reduction reaction between remaining H2O2 and 2,2’-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) to produce a colored compound OxABTS. OxABTS absorbance decreased with increasing contents of melamine and showed a good linear relationship, so as to establish a novel detection method for trace amounts of melamine in dairy products.One-pot hydrothermal approach was used to synthesis gold nanoclusters (AuNCs), sodium cholate was as a stabilizer and a reducing agent. Sodium cholate was a surface biologically active agent, it showed hydrophilic portion and lipophilic portion, chemically distinct functional groups, structural steel and low price and other characteristics, therefore sodium cholate an ideal template for preparing gold nanoclusters. The average diameter of AuNCs was 5 nm, it showed high stability and emited bright blue light under ultraviolet light. On this basis, this work was also used fluorescence enhancement phenomenon of AuNCs to detect melamine in dairy products, the fluorescence intensity of AuNCs with the concentration of melamine exhibited a good linearity, wider detection range (0.025-1.0 nmol I/1) and lower detection limit (2.30 × 10-3 nmol L-1).Fluorescent gold nanoclusters (AuNCs) were synthesized via microwave-assisted hydrothermal method. AuNCs was confirmed as a fluorescent probe for high sensitivity and selectivity detection of creatinine in human blood and urine. When added creatinine to one system, the blue fluorescence of AuNCs would be significantly enhanced, which attributed to the formation of hydrogen bonds between AuNCs caused AuNCs aggregation. The effects of pH, concentration of AuNCs, reaction time and temperature on the detection of creatinine were investigated. Under the optimal conditions, trace amounts of creatinine could be detected. The linear working range is 0.1-100.0 nmol L-1 with a detection 7.54×10-3 nmol L-1 at a signal-to-noise ratio of 3.