Multifunctional TPU-HAp/HA-TiO₂ membranes for prosthesis osteointegration and prevention of in situ infection

Bone defects and implant-associated infections remain major challenges in orthopedic reconstruction, requiring multifunctional biomaterials able to promote osteointegration while preventing bacterial colonization. This work aimed to develop an electrospun nanofibrous membrane based on thermoplastic polyurethane (TPU) and hydroxyapatite (HAp), coated with hyaluronic acid (HA) and functionalized with titanium dioxide (TiO₂) nanoparticles as lining of orthopedic implants. The developed membranes were characterized in terms of morphology, surface properties, mechanical performance, degradation, antibacterial activity, and biological response. The HA-TiO₂-coated membrane showed increased surface wettability and roughness compared with uncoated TPU-based membranes, while maintaining fibrous morphology. After 6 weeks in phosphate-buffered solution, uncoated membranes showed approximately 6% mass loss, whereas HA-coated membranes showed approximately 50% mass loss during the first week, consistent with partial coating removal. The TiO₂-containing membrane reduced bacterial viability after 24 h, corresponding to approximately 1.31 and 1.05 log₁₀ reductions for Escherichia coli and Staphylococcus aureus, respectively. Both human adipose-derived stem cells and SAOS-2 cells adhered to and proliferated on the HA-TiO₂-functionalized membranes, with extracellular matrix sialoprotein deposition observed after 21 days. Subcutaneous implantation in rats for 18 days showed no evident inflammatory or foreign-body response. Overall, the results support the potential of the TPU-HAp/HA-TiO₂ membrane as a multifunctional biomaterial for lining orthopedic implant interfaces, although further bone-specific and infection-relevant in vivo studies are required to establish its osteointegration and infection-prevention efficacy.