Gold Nanoclusters-Based Optical Probe And Its Application In Biological Detection

Gold nanoclusters with ultral-small size(<2 nm) show many molecule-like properties such as size-dependent fluorescence and discrete electronic states. Comparable to gold atom or nanoparticle, it has many advantages, such as high quantum efficiency, excellent stability, good biocompatibility, and good water solubility, etc. Now researchers explore gold nanoclusters as ideal fluorescent probes applying in many aspects. What’s more, gold nanoclusters can use to analyze various samples, but there are a few researches involving in anions analysis and functional modification. However, we find that the gold nanoclusters show similar emission spectrum according to the related reports and functional difficult, which limit its application scope. Therefore, this article contains two part work.In the first section of this work, we used the MUA as the template to prepare the gold nanoclusters, which is red glow. Studies showed that fluorescence intensity and lifetime of the water-soluble gold nanoclusters had good response to the F- with high sensitivity and high selectivity. In addition, we further took a series of experiments to study the mechanism of gold nanoclusters detecting F- such as IR, the fluorescence emission spectrum and absorption and so on. Data of Experiments indicated that the mechanism of gold nanocluster detection may be that the relationship between the F- with the carboxyl in the group of the gold nanoclustes is ptted against the relationship between the Au-S of gold nanoclustes, which hindered the charge transfer of the Au-S bond and lead to change of the fluorescence intensity of gold nanoclusters. What’s more, we succeed applying the gold nanoclusters to deteting F- in biological imaging. To the best of our knowledge, this is the first work about the gold nanoclusters applied to the detection of F- work.In the second section of this work, we used the MUA and THPC as reducing agent and protective agent to prepare the gold nanoclusters. Then we modified the Iridium complex of oxygen probe on the surface of the gold nanoclusters by amidation reaction. Thus, we got a good water solubility ratio oxygen probe, AuNCs-Ir. Under the excitation at 365 nm, the gold nanoclusters showed yellow-green fluorescence and Iridium complex showed orange fluorescence. In water solution, the fluorescence intensity and lifetime of the gold nanoclusters unchanged and the fluorescence intensity and lifetime of the Iridium complex clearly changed. By ratio method, we found probe showed good linear relation under different concentration of oxygen. At last, we succeed applied the probe in biological imaging.