Nanotheranostic Application of Fluorescent Protein-Gold Nanocluster Hybrid Materials: A Mini-review.

The gold nanoclusters (Au NCs) are a special kind of gold nanomaterial containing several gold atoms. Because of their small size and large surface area, Au NCs possess macroscopic quantum tunneling and dielectric domain effects. Furthermore, Au NCs fluorescent materials have longer luminous time and better photobleaching resistance compared with other fluorescent materials. The synthetic process of traditional Au NCs is complicated. Traditional Au NCs are prepared mainly by using polyamide amine type dendrites, and sixteen alkyl trimethylamine bromide or sulfhydryl small molecule as stabilizers. They are consequently synthesized by the reduction of strong reducing agents such as sodium borohydride. Notably, these materials are toxic and environmental-unfriendly. Therefore, there is an urgent need to develop more effective methods for synthesizing Au NCs via a green approach. On the other hand, the self-assembly of protein gold cluster-based materials, and their biomedical applications have become research hotspots in this field. We have been working on the synthesis, assembly and application of protein conjugated gold clusters for a long time. In this review, the synthesis and assembly of protein-gold nanoclusters and their usage in cell imaging and other medical research are discussed.