Mechanochemical exfoliation of graphite

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 facilitates
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 provide 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. Development of
such potentially scalable and toxin-free methods are critical for
producing cost-effective biocompatible graphene, enabling numerous
possible biomedical and biological applications. A methodical study was
performed to identify 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.