Preparation of water‐soluble and biocompatible graphene

Graphene as a two‐dimensional material is particularly attractive because of its excellent electrical conductivity, mechanical properties, large surface area, low coefficient of thermal expansion and very high aspect ratio. However, the water insoluble property of graphene restricts its application in biomedical fields. Therefore the objective of this reported work is to find an efficient way to synthesise water‐soluble and biocompatible graphene for biomedical applications. A stable aqueous graphene oxide (GO) solution was first obtained in the presence of non‐ionic Pluronic copolymer. The GO‐tripolymer showed good solubility in phosphate buffered saline (PBS) and the same UV absorption peaks as GO. Since a traditional reducing agent such as hydrazine had large toxicity, reduced GO (RGO) obtained by hydrazine reduction has some toxicity. In this work, a non‐toxic reducing agent of ascorbic acid, galactose or bovine serum albumin was used as a RGO‐tripolymer solution. The RGO‐tripolymer exhibited good solubility in PBS. Finally, the cytotoxicity of RGO‐tripolymers was investigated. Any RGO‐tripolymer showed low cytotoxicity.