Silver doped titanium oxide–PDMS hybrid coating inhibits Staphylococcus aureus and Staphylococcus epidermidis growth on PEEK

• Hybrid coatings were formulated to release antimicrobial silver.
• The coatings were applied to PEEK, an important orthopedic implant material.
• They inhibited bacterial growth and biofilm formation.
• Sustained release of antimicrobial silver from the coatings was achieved.
• Coating compositions could be adjusted for optimum properties and release.

Bacterial infection remains one of the most serious issues affecting the successful installation and retention of orthopedic implants. Many bacteria develop resistance to current antibiotics, which complicates or prevents traditional antibiotic-dependent eradication therapy. In this study, a hybrid coating of titanium dioxide and polydimethylsiloxane (PDMS) was synthesized to regulate the release of silver. The coatings were benefited from the antimicrobial activity of silver ion, the biocompatibility of titanium dioxide, and the flexibility of the polymer. Three studied silver doped coatings with different titanium dioxide–PDMS ratios effectively inhibited the attachment and growth of Staphylococcus aureus and Staphylococcus epidermidis in a dose-dependent manner. The coatings were successfully applied on the discs of polyether ether ketone (PEEK), a common spinal implant material and antibacterial property of these coatings was assessed via Kirby Bauer assay. More importantly, these selected coatings completely inhibited biofilm formation. The release study demonstrated that the release rate of silver from the coating depended on doping levels and also the ratios of titanium dioxide and PDMS. This result is crucial for designing coatings with desired silver release rate on PEEK materials for antimicrobial applications.

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