Effect of surface properties on the antithrombogenicity of silk fibroin/S-carboxymethyl kerateine blend films

Polymeric blends of silk fibroin (SF) and S-carboxymethyl kerateine (SCMK) were prepared by the solvent casting method to study the effect of surface properties on the antithrombogenicity. The films of SF/SCMK showed better antithrombogenic properties than SF or SCMK alone. Among them, the film containing 50 wt% SCMK showed the best antithrombogenicity. When the SF/SCMK films were treated with methanol, the antithrombogenicity of the films was scarcely affected except the SF-rich ones. The enhanced antithrombogenic properties were explained in terms of polarity of the surface. The blend films showed an enhancement of polar contribution to surface free energy (γ_S^P) and polar stabilization energy (I_sw). SF-rich films showed high γ^P_S and I_sw values when treated with methanol. This change of surface properties was considered to be due to the fact that the conformational transition from random coil structure to β-structure of proteins may have affected the surface properties, especially the polar properties.