Controlled fabrication of biocompatible graphene oxide Langmuir-Blodgett films by size and surface property manipulation

Controlled fabrication of uniform graphene oxide (GO) films is of great demand for many applications such as biomedical and biosensing materials. Surface-supported GO films with different surface coverage and density have been successfully fabricated by Langmuir-Blodgett (LB) method. The dialyzed GO sheets with sizes of smaller than 200 nm are used for LB assembly so as to achieve well control over the quality of the GO films. The dialysis procedure can remove soluble impurities from the GO sheets to adjust the surface composition and physicochemical properties. GO sheets within nanometer sizes can avoid edge folding and stacking during LB assembly and get better control of interactions between GO sheets. These aspects help to fabricate the uniform LB assemblies of GO sheets successfully, which can then be transferred onto the solid surface to give GO films with controlled surface coverage and density. The surface-supported GO films show high stability and biocompatibility, which can mediate cell growth and proliferation. The study not only provides ways for controlling the physicochemical properties of the GO sheets but also depicts the controlled fabrication of uniform GO films for specific applications.