Polydopamine (PDA) mediated nanogranular-structured titanium dioxide (TiO2) coating on polyetheretherketone (PEEK) for oral and maxillofacial implants application

Polyetheretherketone (PEEK) is being used in various biomedical devices thanks to its bio-inertness, nontoxicity, and an elastic modulus near to that of human cortical bone. However, its oral and maxillofacial applications remain challenging owing to is hydrophobicity, lack of biocompatibility, and infectious complications. To address this problem, a biocompatible nanogranular-structured TiO2 coating assisted by a mediating layer of pregrafted polydopamine (PDA) was deposited onto PEEK to modify its surface. The PDA-mediated TiO2 coated PEEK showed a unique surface layer of single anatase phase. The surface tended to become more hydrophilic with increased TiO2 deposition, and even turned super-hydrophilic with a sufficient amount of deposited TiO2. In vitro cell culture tests verified that such prepared PEEK improved adhesion and proliferation of both fibroblast and osteoblast cells, decreased the inflammatory reaction by suppressing TNF-a expression for macrophages, as well as enhanced the antibacterial activity against Staphylococcus aureus and Streptococcus mutans bacteria attachment when compared to only PDA coated and uncoated PEEK. Such a superior bio-performance is apparently correlated with anatase TiO2, as well as its improved physiochemical surface states, including altered surface energy. The PDA-mediated TiO2 nanostructured coating may bode well for oral and maxillofacial implants applications of PEEK.