CVD graphene transfer procedure to the surface of stainless steel for stem cell proliferation

Graphene is an attractive material for tissue engineering due to its good interaction with cells (adhesion and proliferation) and its ability to protect the surface of biomaterials against corrosion. CVD graphene is a suitable candidate among the various types of graphene since it can cover large areas, however, the transfer process to the target substrates still involves several steps including the etching of metal used in chemical vapor deposition. Here, a new route of CVD graphene transfer process to the surface of austenitic stainless steel (ASS) is presented taking the advantage of not requiring an etching step. The structural stability of graphene transferred to the ASS surface was evaluated in SBF (simulated blood fluid) as well as for stem cell attachment and proliferation. CVD graphene was successfully transferred to a stainless steel surface in two steps: 1) Directly from a polymer film without the etching of copper (Direct Dry Transfer method - DDT); 2) Graphene transfer from the polymer to the ASS surface using temperature and pressure and the removal of the polymer by solvent. The area covered by graphene on the ASS surface varied according to the transfer parameters (pressure and time) and roughness of the substrate. Raman mapping results showed that graphene transferred to ASS surfaces presents a distinct structural stability in SBF of up to 28 days. All samples tested allowed mesenchymal stem cell attachment and their proliferation. The success of the transfer procedure, the structural stability presented by the graphene under ASS, its attachment capacity, and proliferation of cells provides new opportunities for graphene as a covering material for tissue engineering.