Low Percent Copper Doping Limits Bacterial Adhesion on Fluorapatite-Based Bone Scaffolds

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Infectious Disease Research

Background:

• Bone grafts are crucial for reconstruction but susceptible to infection.
• Fluorapatite (FAp) is osteoconductive but lacks antimicrobial properties.
• Copper (Cu) doping offers antimicrobial potential but requires careful concentration control.

Purpose of the Study:

• To investigate low-concentration Cu doping (0.25-1.0 mol%) in FAp to create infection-resistant bone grafts.
• To assess the antibacterial efficacy and osteogenic compatibility of Cu-doped FAp (CuFAp).
• To evaluate CuFAp scaffolds in a preclinical model of contaminated bone defects.

Main Methods:

• Synthesized and characterized CuFAp with varying Cu concentrations (0.25-1.0 mol%).
• Assessed antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.
• Evaluated osteoblast viability and proliferation on CuFAp surfaces.
• Tested 0.50 mol% CuFAp scaffolds in a rat critical-size bone defect model.

Main Results:

• Successful Cu substitution in the FAp lattice confirmed, with increased grain size.
• 0.25-0.50 mol% CuFAp significantly reduced bacterial adhesion (up to 3 log-fold).
• Osteoblast viability was maintained over 72 hours at all tested Cu concentrations.
• In vivo studies showed complete bone regeneration with minimal inflammation in contaminated defects.

Conclusions:

• Low-concentration Cu doping (0.25-0.50 mol%) in FAp enhances antibacterial properties without compromising osteogenic potential.
• 0.50 mol% CuFAp scaffolds demonstrate efficacy in promoting bone regeneration in infected defects.
• CuFAp represents a promising biomaterial for developing infection-resistant bone grafts.