Atomistic understanding of interfacial interactions between bone morphogenetic protein-7 and graphene with different oxidation degrees
Bone morphogenetic protein (BMP) adsorption plays an important role in the osteoinduction properties of graphene (G)-based biomaterials. Meanwhile, the physical and chemical properties of G vary in a large range according to the different oxidation degrees. In this study, molecular dynamic simulations were utilized to understand the interfacial interactions of G's oxidation degree on the BMP-7 adsorption behaviors. According to the adsorption energy, the distance distribution of BMP-7 adsorption sites/G, and artificial intelligence based principal component analysis, the effects of G's oxidation degree on BMP-7 adsorption were systematically studied. Then, the variations of the BMP-7 configuration were explored by the analysis of the secondary structures, root mean square deviation and Ramachandran plots. It is indicated that the adsorption of BMP-7 on G is strongly related to its oxidation rate. The surface polarities and the wrinkle degrees of G can be regulated by the oxidation rate and consequently impact the interactions between BMP-7 and G. A 50% oxidation degree of G exhibits the equilibrated regulation effects on both the adsorption strength and the configurations of BMP-7. Our study provides critical information on the relationship between BMP-7 adsorption and the oxidation degree of G at the atomistic scale, which can guide the design of novel BMP-7 loaded G-based tissue engineering scaffolds.