Preventing Antibiotic-Resistant Infections: Additively Manufactured Porous Ti6Al4V Biofunctionalized with Ag and Fe...

Area of Science:

• Biomaterials Engineering
• Nanotechnology
• Orthopedic Surgery

Background:

• Implant-associated infections pose a significant clinical challenge, exacerbated by multidrug-resistant microbes.
• Surface modification of implants is crucial for preventing infection and enhancing osseointegration.
• Silver (Ag) doping shows antibacterial efficacy but can impede bone regeneration at high concentrations.

Purpose of the Study:

• To investigate the synergistic antibacterial effects of co-immobilizing silver (Ag) and iron (Fe) nanoparticles (NPs) on additively manufactured porous titanium.
• To evaluate the impact of Ag/Fe NP co-functionalization on implant biocompatibility and bone regeneration.
• To develop a novel strategy for preventing implant-associated infections while promoting bone healing.

Main Methods:

• Additively manufactured porous titanium scaffolds were surface-biofunctionalized using plasma electrolytic oxidation with a Ca/P-based electrolyte containing Ag NPs, Fe NPs, or both.
• Surface morphology and elemental composition were analyzed.
• In vitro antibacterial assays were performed against methicillin-resistant *Staphylococcus aureus* and *Pseudomonas aeruginosa*.
• Preosteoblast proliferation and calcium-sensing receptor activation were assessed.

Main Results:

• The biofunctionalized titanium surfaces exhibited porous TiO2 structures embedded with Ag and Fe NPs.
• Sustained release of Ag and Fe ions was observed for up to 28 days.
• Specimens with Ag NPs and Ag/Fe NPs demonstrated significant bactericidal activity against tested pathogens.
• Synergistic antibacterial effects were observed, allowing for a threefold reduction in Ag concentration.
• The Ag/Fe NP-functionalized scaffolds enhanced preosteoblast proliferation and Ca-sensing receptor activation, indicating improved biocompatibility.

Conclusions:

• Surface biofunctionalization of porous titanium with Ag and Fe NPs is a viable strategy for preventing implant-associated infections.
• The synergistic action of Ag and Fe NPs reduces the required Ag concentration, mitigating potential adverse effects on bone regeneration.
• This approach holds significant promise for clinical applications in orthopedic surgery, promoting both infection prevention and bone healing.