Surface modification of silk fibroin with poly(ethylene glycol) for antiadhesion and antithrombotic applications

Silk fibroin film surfaces were PEGylated by reaction with cyanuric chloride-activated poly(ethylene glycol) (PEG). Reactions with different concentrations of activated PEG generated films with PEG graft densities from 0.02 to 0.4 mg per square cm of silk fibroin. Increased PEGylation resulted in increased hydrophilicity as analyzed by contact angle, and a smoother morphology based on scanning electron microscopy. Increased PEGylation decreased human IgG adsorption and decreased the attachment and proliferation of human fibroblasts over two weeks. Increased concentration of PEG on the silk fibroin surfaces also decreased the proliferation of human mesenchymal stem cells and inhibited human platelet attachment. Surface PEGylated silk fibroin films could be useful antiadhesion and antithrombotic materials for biomedical applications when considered along with the unique mechanical and tailorable degradation profiles of silk fibroin.