In vitro antimicrobial activity of vancomycin-eluting bioresorbable β-TCP-polylactic acid nanocomposite material for load-bearing bone repair

Release of antimicrobial agents from bone healing devices can dramatically reduce the risk of implant-associated infection. Here we report the fabrication and antimicrobial activity of a multifunctional load-bearing bioresorbable material that can provide mechanical support to the healing bone all while slowly releasing an antibiotic drug. Dense beta-tricalcium phosphate (beta-TCP)-40 vol% polylactic acid (PLA) nanocomposite containing 1 wt% vancomycin (VH) was high pressure consolidated at 2.5 GPa, at room temperature, or at 120 A degrees C. Over the course of 5 weeks in TRIS solution, the beta-TCP-PLA-VH nanocomposite released approximately 90 % of its drug load. Specimens consolidated at 120 A degrees C had the highest initial mechanical properties and maintained 85 % of their compressive strength and 30 % of their bending strength after 5 weeks release. In vitro growth inhibition study showed significant antimicrobial efficacy of VH-impregnated beta-TCP-PLA against methicillin-resistant Staphylococcus aureus when exposed to both high (2 x 10(5) CFU/mL) and very high (1 x 10(8) CFU/mL) bacterial concentrations. After 1 week, total eradication of the microorganisms was achieved. The results suggest that the developed high-strength antibiotic-eluting beta-TCP-PLA nanocomposite can be a promising material for orthopedic surgical devices.