Au 3+ -Induced gel network formation of proteins

The formation of protein gel networks in aqueous systems is a result of protein intermolecular interactions after an energy input, like heating. In this research, we report that a redox reaction between Au 3+ ions and proteins can also lead to the formation of a protein gel network. Amino acids, like cysteine and tyrosine, get oxidized and form covalent bonds with neighboring protein molecules, while Au 3+ ions get reduced to Au + and Au 0 , nucleate and form gold nanoparticles. The protein gel network formation occurs within 2 h at room temperature and can be tuned by varying Au 3+ /protein ratio and accelerated by increasing the incubation temperature. The proposed Au 3+ -induced gel network formation was applied to different proteins, like egg yolk high-density lipoprotein, bovine serum albumin and whey protein. This research opens new insights for the investigation of the metal–protein interactions and may aid in the design of novel hybrid-soft nanocomposite materials.