Characterization of a fluorescence probe based on gold nanoclusters for cell and animal imaging

A facile approach to synthesize gold nanoclusters (Au NCs) with bluish green fluorescence using histidine as both reductant and capping agent was reported. The UV-visible absorption and photoluminescence spectra measurement was performed to explore its optical properties under different circumstances (preparing condition, temperature, pH, storing time). Then, MPA, a NIR organic dye, was conjugated to Au NCs (Au-MPA) for in vivo fluorescence imaging application. Low cytotoxicity and high affinity to tumor of this nanoprobe was proved at the cellular level, and its bio-distribution in normal nude mice and MCF-7 tumor-bearing mice was also investigated. Consequently, the results demonstrated the promising potential of the green Au NCs conjugated with NIR dye as nanoprobes in bioimaging and related fields.