Antibacterial and Osteogenic Functionalization of Titanium With Silicon/Copper-Doped High-Energy Shot Peening-Assisted Micro-Arc Oxidation Technique

Xinkun Shen; Wenjia Hu; Linchao Ping; Chongxing Liu; Lili Yao; Zhennan Deng; Gang Wu

doi:10.3389/fbioe.2020.573464

Antibacterial and Osteogenic Functionalization of Titanium With Silicon/Copper-Doped High-Energy Shot Peening-Assisted Micro-Arc Oxidation Technique

Front Bioeng Biotechnol. 2020 Oct 8:8:573464. doi: 10.3389/fbioe.2020.573464. eCollection 2020.

Authors

Xinkun Shen¹, Wenjia Hu¹, Linchao Ping¹, Chongxing Liu¹, Lili Yao¹, Zhennan Deng¹, Gang Wu^{2

3}

Affiliations

¹ School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
² Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Science, University of Amsterdam and Vrije University Amsterdam, Amsterdam, Netherland.
³ Department of Oral and Maxillofacial Surgary/Pathology, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universitetit Amsterdam, Amsterdam Movement Science, Amsterdam, Netherlands.

Abstract

Antibacterial and osteogenic functionalization of titanium (Ti) implants will greatly expand their clinical indications in immediate implant therapy, accelerate osteointegration, and enhance long-term prognosis. We had recently shown that the high-energy shot peening (HESP)-assisted micro-arc oxidation (MAO) significantly improved the bioactivity and coating stability of Ti-based substrates. In this study, we further functionalized Ti with antibacterial and osteogenic properties by doping silicon (Si) and/or copper (Cu) ions into HESP/MAO-treated coatings. Physicochemical characterization displayed that the doping of Si and Cu in HESP/MAO-treated coatings (Si/Cu-MAO) did not significantly change their surface topography, roughness, crystal structure, coating thickness, bonding strength, and wettability. The results of X-ray photoelectron spectroscopy (XPS) showed that Si and Cu in the Si/Cu-MAO coating was in the form of silicate radical (SiO₃ ^2-) and bivalent copper (Cu²⁺), respectively. The total amounts of Si and Cu were about 13.5 and 5.8 μg/cm², which released about 33.2 and 31.3% within 14 day, respectively. Compared with the control group (MAO), Si doping samples (MAO-Si) significantly increased the cell viability, alkaline phosphatase (ALP) activity, mineralization and osteogenic genes (ALP, collagen I and osteocalcin) expression of MC3T3-E1 cells. Furthermore, the addition of Cu presented good bactericidal property against both Staphylococcus aureus and Streptococcus mutans (even under the co-culture condition of bacteria and MC3T3-E1 cells): the bacteriostatic rate of both bacteria was over 95%. In conclusion, the novel bioactive Si/Cu-MAO coating with antibacterial and osteogenic properties is a promising functionalization method for orthopedic and dental implants, especially in the immediate implant treatment with an infected socket.

Keywords: antibacterial; high-energy shot peening; micro-arc oxidation; osteogenesis; titanium.