Fabrication, Mechanical Properties, and Biocompatibility of Graphene-Reinforced Chitosan Composites

TLDR

Graphene/chitosan composites are potential scaffold materials for tissue engineering. Graphene sheets were synthesized by DC arc‑discharge, dispersed in chitosan/acetic acid, cast into films, and their mechanical properties were evaluated by nanoindentation while biocompatibility was assessed in vitro. Adding 0.1–0.3 wt % graphene to chitosan raised the elastic modulus by over 200 %, and the composites supported L929 cell adhesion comparable to pure chitosan, while the absence of metal impurities obviates purification steps.

Abstract

Few-layered graphene sheets, synthesized by direct current arc-discharge method using NH3 as one of the buffer gases, were dispersed in chitosan/acetic acid solutions. FTIR and X-ray photoelectron spectroscopy showed the presence of oxygen-containing functional groups on the surface of graphene sheets that may assist the good dispersion of graphene in chitosan solution. Graphene/chitosan films were produced by solution casting method. The mechanical properties of composite films were tested by nanoindentation method. With the addition of a small amount of graphene in chitosan (0.1−0.3 wt %), the elastic modulus of chitosan increased over ∼200%. The biocompatibility of graphene/chitosan composite films was checked by tetrazolium-based colorimetric assays in vitro. The cell adhesion result showed that the L929 cell can adhere to and develop on the graphene/chitosan composite films as well as on pure chitosan film, indicating that graphene/chitosan composites have good biocompatibility. Because there is no metallic impurity in graphene raw materials, the time-consuming purification process for removing metal nanoparticles entrapped in carbon nanotubes is thus avoided when graphene is used to prepare biomedical materials. Graphene/chitosan composites are potential candidates as scaffold materials in tissue engineering.