Antibacterial activities and cytocompatibility of zinc-contained strontium phosphate coating on titanium

Abstract

Periprosthetic joint infection (PJI) is one of the most pivotal issues accounting for clinical failure of titanium (Ti)-based implants. Therefore, it is of great significance to develop an antibacterial coating with high biocompatibility on the Ti implant surface. In this article, a novel zinc-doped strontium phosphate coating, denoted as Sr-Zn-PCC, was deposited on Ti substrates by phosphate chemical conversion (PCC) method. The texture characterizations indicated that continuous coatings containing SrHPO4, Sr3(PO4)2 and SrZn2(PO4)2 phases were formed on the Ti surface. It is found that the doping of Zn could tune the surface microstructure, roughness, wettability and corrosion resistance of the coatings. The Sr-Zn-PCC coating showed the same bacterial adhesion property at short time (2 h), but tended to hinder biofilm formation on coatings after incubation for up to 24 h. Up to 80% of Staphylococcus aureus (S. aureus) were killed within 24 h by contact with the Sr-Zn-PCC surface. Moreover, cytocompatibility assay indicated that MC-3T3 cells had good adhesion, spreading properties on the coatings, suggesting that it is a promising alloy with both excellent antibacterial ability and high biocompatibility for the applications on orthopedic implants.

Zinc-Doping Induces Evolution of Biocompatible Strontium–Calcium-Phosphate Conversion Coating on Titanium to Improve Antibacterial Property

“…In our previous study, the formation mechanism of Sr-PCC and Sr–Zn–PCC coatings prepared on Ti by PCC method has been proposed . In this research, the SrCaP coating is constructed based on the Sr-PCC coating by adding Ca to the PCC solution.…”

“…It is an essential requirement for implant materials to have biocompatibility to meet clinical needs . Sr, Zn, and Ca are all considered to be necessary elements for human metabolism. , The evaluation of the biocompatibility of Zn-doped coatings was carried out by Live & Dead, EdU, and CCK-8 assays. As shown in Figure , almost no dead cells can be observed on the surface of all sample groups, indicating that different coatings with or without Zn-doping all display excellent biocompatibility.…”

“…In our previous study, the formation mechanism of Sr-PCC and Sr−Zn−PCC coatings prepared on Ti by PCC method has been proposed. 51 In this research, the SrCaP coating is constructed based on the Sr-PCC coating by adding Ca to the PCC solution. As elements of the same main group, Sr and Ca have chemical similarities and a small difference in ionic radius (Sr 2+ =1.13 Å, Ca 2+ =0.96 Å).…”

“…72 Sr, Zn, and Ca are all considered to be necessary elements for human metabolism. 14,51 The evaluation of the biocompatibility of Zn-doped coatings was carried out 9, almost no dead cells can be observed on the surface of all sample groups, indicating that different coatings with or without Zn-doping all display excellent biocompatibility. The cells present red fluorescence in Figure 10a indicating EdU labeling after the EdU incorporation assay, and the rates of EdU-positive cells are similar in these four groups at 48 h (Figure 10b).…”