Surface functionalization of titanium substrates with cecropin B to improve their cytocompatibility and reduce inflammation responses.

Bacteria-related inflammation is a common postoperative complication in orthopedic implantation. In this study, cecropin B (CecB), a cationic peptide, was immobilized onto the surfaces of titanium substrates to improve their cytocompatibility and reduce inflammation responses. Polydopamine film was coated onto the surfaces of titanium substrates as an intermediate layer for the further immobilization of the CecB, which was confirmed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement, respectively. Osteoblasts grown onto the CecB-immobilized titanium substrates displayed significantly higher (p<0.01) cell viability than that of native titanium substrates (controls). Gram-positive bacteria - Bacillus subtilis, Staphylococcus aureus and Gram-negative bacteria - Escherichia coli, Pseudomonas aeruginosa were employed for antibacterial characterization. Media-borne assay and anti-biofilm formation showed that CecB-immobilized titanium substrates inhibited the adhesion and growth of bacteria. Macrophages cultured onto CecB-immobilized titanium substrates demonstrated statistically lower (p<0.01) levels of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) than those of the control groups. The results indicated that the immobilization of CecB onto titanium substrates was responsible for improved cytocompatibility and reduced inflammation responses. The approach presented here has great potential in the development of antibacterial titanium-based implants in clinical applications.