Protein-assisted scalable mechanochemical exfoliation of few-layer biocompatible graphene nanosheets

Abstract

A facile method to produce few-layer graphene (FLG) nanosheets is developed using protein-assisted mechanical exfoliation. The predominant shear forces that are generated in a planetary ball mill facilitate the exfoliation of graphene layers from graphite flakes. The process employs a commonly known protein, bovine serum albumin (BSA), which not only acts as an effective exfoliation agent but also provides stability by preventing restacking of the graphene layers. The latter is demonstrated by the excellent long-term dispersibility of exfoliated graphene in an aqueous BSA solution, which exemplifies a common biological medium. The development of such potentially scalable and toxin-free methods is critical for producing cost-effective biocompatible graphene, enabling numerous possible biomedical and biological applications. A methodical study was performed to identify the effect of time and varying concentrations of BSA towards graphene exfoliation. The fabricated product has been characterized using Raman spectroscopy, powder X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The BSA-FLG dispersion was then placed in media containing Astrocyte cells to check for cytotoxicity. It was found that lower concentrations of BSA-FLG dispersion had only minute cytotoxic effects on the Astrocyte cells.

Biocompatible 2D Materials via Liquid Phase Exfoliation

“…Graphite can also be exfoliated by ball milling using BSA as an intercalating agent. [ 94 ] The BSA‐coated graphene showed negligible cytotoxicity on astrocytes at a low concentration, but induced cell death at a higher concentration. The cytotoxicity was mainly derived from residual endotoxins in BSA, as endotoxins can trigger inflammatory responses and further lead to a deleterious impact on cells.…”