Sensors Based On Gold Nanoclusters

As a new kind of luminescent nanomaterials, metal nanoclusters(NCs) have diameters below 2 nm typically. With the size approaching the Fermi wavelength of electrons, metal NCs display electrical, optical and chemical properties different from that of nanoparticles dramatically. With their distinct properties, such as strong photoluminescence, excellent photostability and good biocompatibility, metal nanoclusters are often used in the detection of targets as fluorescent probes. And most of the detection principles are based on fluorescence quenching or enhancement of metal nanoclusters. We developed a series of biosensors based on the fluorescence quenching effect from targets in this work.In the first part of this work, gold nanoclusters were synthesized with bovine serum albumin(BSA) as the template material. As proved by the experiments, the fluorescence of the nanoclusters was not affected by adding iodide alone,but when iodide mixed together with hydrogen peroxide, the quenching from hydrogen peroxide was significant enhanced. During this process, iodide was oxidized into element iodine and the so produced I2/I- mixture provided a powerful etchant toward gold. Thus a sensitive detection toward hydrogen peroxide was obtained.In the second part of this work, since hydrogen peroxide was the product of a series of enzyme reaction. Analysis of the substrates could be achieved through measurement of hydrogen peroxide. Based on this principle, fluorescent sensors toward glucose and uric acid were developed. Due to their high sensitivity, easy operation and low cost, the so-developed sensors have a significant potential application in clinical diagnosis and disease detection.