Synergism of microgrooves and gallium phytate coating on PEKK based percutaneous implant with photothermal effect facilitates biological sealing of skin tissue for combating infection.

The success of percutaneous implants not only involves integration with bone tissue but also requires integration with soft tissue to form bio-sealing, which effectively prevents epithelial downgrowth and resists infection. Herein, black niobium oxide/polyetherketoneketone (PEKK) composite (BNP) with photothermal performance was fabricated, and microgrooves with widths of 30 μm, 50 μm, and 80 μm were created on BNP by femtosecond laser. BNP with a width of 50 μm (BNPg50) obviously facilitated the responses (e.g., migration and differentiation) of fibroblasts (L929 cells) and epidermal keratinocytes (JB-6 cells), and their co-culturing as well as stimulated macrophage M2 polarization. Moreover, gallium phytate (GP) was coated on BNPg50 (BNPgG), which exhibits excellent antibacterial properties for killing bacteria in vitro and resisting infection in vivo due to the synergism of Ga ions and photothermal effect. Further, BNPgG obviously facilitated the proliferation of bone marrow mesenchymal stem cells (BMSCs) while inhibiting bacterial growth under near infrared in co-culturing of cells and bacteria. The in vivo experiments demonstrated that synergies of microgrooves, GP coating, and photothermal effect remarkably encouraged bio-sealing of skin tissue for combating infection. This fundamental research advanced the understanding of soft tissue responses and biological sealing around implants, thereby highlighting their great potential for accelerating the application of percutaneous implants.