A Simple Approach to Design Proteins for the Sustainable Synthesis of Metal Nanoclusters.

Metal nanoclusters (NCs) are considered ideal nanomaterials for biological applications owing to their strong photoluminescence (PL), excellent photostability, and good biocompatibility. This study presents a simple and versatile strategy to design proteins, via incorporation of a di-histidine cluster coordination site, for the sustainable synthesis and stabilization of metal NCs with different metal composition. The resulting protein-stabilized metal NCs (Prot-NCs) of gold, silver, and copper are highly photoluminescent and photostable, have a long shelf life, and are stable under physiological conditions. The biocompatibility of the clusters was demonstrated in cell cultures in which Prot-NCs showed efficient cell internalization without affecting cell viability or losing luminescence. Moreover, the approach is translatable to other proteins to obtain Prot-NCs for various biomedical applications such as cell imaging or labeling.