Protein-Mediated Synthesis of Au Nanocluster Decorated Reduced Graphene Oxide: A Multifunctional Hybrid Nano-Bio Platform

The seamless integration of functional biomolecules with advanced nanomaterials not only allows for a hybrid material yielding their combined properties but also can enable novel joint functionality. In this work, the protein bovine serum albumin is used to simultaneously reduce and stabilize graphene oxide, demonstrating complete reduction of the graphene oxide to its reduced graphene oxide form. Where previous work has utilized a protein-reduced graphene oxide hybrid material as an attachment point for subsequent metal nanoparticle binding, this effort establishes an in situ methodology to directly synthesize tailored metal nanoclusters within the stabilizing protein complex. The successful synthesis of gold metal nanoclusters within the protein component of the hybrid system is verified, allowing for the creation of high-density protein-nanocluster ensembles on the graphene substrate. Utilizing the sensitive nature of the high-density protein-nanocluster materials, a protease sensor platform is demonstrated to detect the presence of trypsin, which is a biomarker for acute pancreatitis, at concentrations below 100 ng/mL.