Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface

Area of Science:

• Biomaterials Science
• Nanotechnology
• Surface Chemistry

Background:

• Hydroxyapatite (HA) coatings on implants enhance osseointegration but risk bacterial colonization.
• Developing antibacterial implant surfaces is crucial for preventing post-surgical infections.

Purpose of the Study:

• To create an antibacterial hydroxyapatite surface by immobilizing silver nanoparticles (Ag NPs) using a polydopamine (PDA) intermediate layer.
• To evaluate the antibacterial efficacy and stability of the functionalized implant surface for medical applications.

Main Methods:

• Stainless steel 316L was coated with PDA, followed by Ag NP metallization (12-24h immersion).
• A second PDA layer was applied, then biomineralization in Simulated Body Fluid (SBF) for 3 days.
• Surface characterization used X-ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy, and Contact Angle measurements.

Main Results:

• Successful immobilization of Ag NPs and HA agglomerations on the PDA film was confirmed.
• Ag metallization for 24 hours achieved a 97.88% bactericidal ratio against viable bacteria.
• Silver ions were released for up to 7 days, crucial for early infection prevention.

Conclusions:

• The developed PDA-Ag-HA functionalized surface exhibits significant antibacterial properties and stability.
• This coating technology is suitable for complex metal surfaces in dental and orthopedic implants.
• The method offers a promising strategy for creating infection-resistant medical implants.