Photothermal Lubricating Composite Hydrogel Coating with Hydrated Polymer Brushes and Load‐Bearing Micropores on Ti6Al4V Implants

While titanium alloys like Ti6Al4V for joint implant are noted for their high strength, low density, and excellent biocompatibility, their clinical application is often hindered by poor wear resistance and insufficient bioactivity. Although various surface modification strategies have been explored to address these issues, the results have remained less than optimal. The purpose of this study is to develop a more effective strategy to maximize the function of Ti6Al4V as joint implant material. Hence, a photothermal lubricating composite hydrogel coating combining load-bearing micropores and hydrophilic polymer brushes is introduced on the Ti6Al4V surface. This microporous frame not only maintains the mechanical stability of the composite coating but also acts as a water reservoir, continuously replenishing water to the friction interface. The polymer brushes grafted within the micropores establish a stable hydration layer, significantly enhancing hydration lubrication performance of the composite coating. Furthermore, the composite coating can generate localized heat under near-infrared light due to its inherent photothermal effect, enabling rapid bacterial elimination and offering a strategy to reduce the risk of tissue infection. This multi-modification approach endows the composite coating with wear resistance, ultralow friction, and efficient antibacterial properties, enabling Ti6Al4V to achieve their maximum efficacy in the biomedical field.