LAUSR

Graphene-based materials (GBMs) have been increasingly explored for biomedical applications. However, interaction between GBMs-surfaces and bacteria, mammalian cells, and blood components - the major biological systems in our body - is still poorly understood. In this study, we systematically explore the features of GBMs that most strongly impact the interactions of GBMs films with plasma proteins and biological systems. Films produced by vacuum filtration of GBMs with different oxidation and thickness depict different surface topography: graphene oxide (GO) and few-layer GO (FLGO) films are more oxidized, smoother and hydrophilic, while reduced GO (rGO) and few-layer graphene (FLG) are less or non-oxidized, rougher and more hydrophobic. All films promote glutathione oxidation, although lower by rGO, indicating their potential to induce oxidative stress in biological systems. Human plasma proteins, which mediate most of the biological interactions, adsorb less to oxidized films than to rGO and FLG. Similarly, clinically relevant bacteria - Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli - adhere less to GO and FLGO, while rGO and FLG favor bacterial adhesion and viability. Surface features caused by oxidation degree and thickness of the GBMs powders within the films have less influence towards human foreskin fibroblasts: all materials allow cell adhesion, proliferation and viability up to 14 days, despite less on rGO surfaces. Blood cells adhere to all films, with higher numbers in less or non-oxidized surfaces, despite none caused hemolysis (<5%). Unlike thickness, GBMs oxidation degree of GBMs platelets strongly impact surface morphology/topography/chemistry of the films, consequently affecting protein adsorption, and thus bacteria, fibroblasts and blood cells response. Overall, this study provides useful guidelines regarding the choice of the GBMs to use in the development of surfaces for an envisioned application. Oxidized materials appear as the most promising for biomedical applications that require low bacterial adhesion without being cytotoxic to mammalian cells.