Study On Optical Analysis Method Based On Metal Nanoclusters

With the development of nano-science, nano-materials have been used in physics, chemistry, materials, biology, mechanics and other fields. As a kind of new fluorescent nanomaterial, metal nanoclusters have many advantages such as small size, strong fluorescence, stable against aggregation, large stokes shift and good biocompatibility. In recent years, metal nanoclusters have been widely used in establishing biochemistry sensors and cell imaging. This paper would focus on the study of chemiluminescence properties of gold nanoclusters and fluorescence properties of copper nanoclusters and explore the new applications of metal nanoclusters in biosensing.This thesis is divided into two chapters. The first chapter is the review, a brief introduction to the basic concepts of metal nanoclusters, summed up the synthesis, optical properties and applications in biosensing of metal nanoclusters. The second chapter is the research report consisted of two parts as follows.1. Determination of trypsin by chemiluminescence based on gold nanoclusters-H202-G-quadruplex-hemin DNAzyme systemThis work introduced BSA stabilized gold nanoclusters (BSA-Au NCs) into chemiluminescence analysis and successfully constructed Au NCs-H2O2-DNAzyme chemiluminescence system. The effects of pH and metal ions on the chemiluminescence intensity of Au NCs-H2O2-DNAzyme system were investigated. We also discussed the chemiluminescent properties of Au NCs-H2O2-DNAzyme system. Thereby, a new method for chemiluminescent determination of trypsin was established attributed to the hydrolysis of the BSA templates in the presence of trypsin. A good linear relationship was obtained between the CL intensity and the concentrations of trypsin in the range of 1.0×10-10 g/mL to 1.0×10-7 g/mL and 1.0×10-7 g/mL to 1.0×10-5 g/mL respectively with a detection limit at 28 pg/mL which was 71 times lower than the fluorescent method. This work would extend the research field of metal nanoclusters and promote the chemiluminescence applications in the field of biochemistry and analytical determination.2. Poly(thymine)-templated copper nanoclusters as fluorescent probes for the detection of L-cysteineA simple and sensitive method for the detection of L-cysteine was established using fluorescent copper nanoclusters (Cu NCs) synthesized by polythymine (poly T) as a probe. In the presence of L-cysteine, the fluorescence of Cu NCs was tremendously quenched through a robust Cu-S bond between -SH in cysteine molecule and Cu of Cu NCs. Compared with the conventional assay, the experiment can be completed within 10 minutes without any separation steps. Under the optimized experimental conditions, the probe exhibited excellent performance in the range from 3μM to 50μM with a detection limit of 0.56μM. Moreover, the developed bioassay was successfully applied to selective detection and determination of L-cysteine in human urine samples.