Mixed protein templated fluorescent gold-nanoclusters allow folic acid sensing

Protein templated nanoclusters, specifically gold nanoclusters (AuNCs), have attracted a great deal of attention in the recent years due to their biocompatibility, intense fluorescence, sensing and imaging capabilities. Often, expensive and exotic proteins with limited environmental, chemical, and thermal stabilities have been used. Herein, we present a facile and low cost, synthesis of thermally and environmentally stable, photoactive AuNCs. The protein chosen in this study is chicken egg white (EW), which contains approximately 148 different proteins including ovalbumin, lysosomes, ovotransferrin and tryptophan. The fluorescence emission spectrum of the albumen-templated AuNCs are controllable via pH of the solution. The color tunable EW:AuNC exhibit a high degree of sensitivity to folic acid (FA), offering a sensitive sensor platform for simultaneous sensing and imaging of the vitamin.