A Simple Flow Reactor for Continuous Synthesis of Biographene for Enzymology Studies

The unique properties of graphene make it an intriguing platform for the attachment and enhancement of biological molecules, but it has yet to achieve its full potential in terms of biological applications. Single-layer graphene is expensive, making alternatives to this material highly desired for applications that require high-quality graphene in large quantities. In this context, we report a simple, environmentally friendly, nonlabor-intensive method for the synthesis of colloidal graphene suspensions of 3-5 layers, stabilized by bovine serum albumin, in water. The method involves a flow reactor designed to continually yield high-quality graphene colloids, synthesized, purified, and optimized all in one setup. The flow reactor is able to produce colloidal graphene sheets on a multigram scale, and these colloids were characterized by Raman spectroscopy, electron microscopy, and zeta potential studies. The average size of the sheets is 0.16μm², each consisting of 3-5 layers of graphene with little or no sp³ defects. These graphene colloids stabilized by the protein were successfully used in protein kinetic studies as well as in surface plasmon resonance protein binding studies. The ease of synthesis of these high-quality graphene colloidal suspensions in water provides an exciting opportunity for biographene to be used on an industrial scale for electronic, thermal, and enzymology applications.