Mass Production of Biocompatible Graphene Using Silk Nanofibers.

Mass production of high-quality graphene dispersions under mild conditions impacts the utility of the material for biomedical applications. Various proteins have been used to prepare graphene dispersions, rare sources, and expensive prices for these proteins restrict their large-scale utility for the production of graphene. Here, inexpensive silk proteins as an abundant resource in nature were used for graphene exfoliation. The silk proteins were assembled into hydrophobic nanofibers with negative charge, and then optimized for the production of graphene. Significantly higher concentrations (>8 mg mL) and yields (>30%) of graphene dispersions under ambient aqueous conditions were achieved compared with previous protein-assisted exfoliation systems. The exfoliated graphene exhibited excellent stability in water and fetal bovine serum solution, cytocompatibility, and conductivity, suggesting a promising future in biomedical and bioengineering applications.