Brush-like copolymer and MXene-functionalized PVA/PEEK scaffolds: enhancing lubrication in metatarsophalangeal joint prostheses.

Prosthetic wear remains a key challenge in metatarsophalangeal (MTP) joint replacement, where improved lubrication is essential for reducing interfacial wear and extending implant lifespan. Inspired by the lubrication mechanisms of natural joints, this study proposes a biomimetic strategy that combines a brush-like copolymer with two-dimensional nanomaterials to enhance the tribological performance of artificial MTP joint materials. A brush-like polymer (HAPA) was synthesized by covalently grafting PAMPS side chains onto hyaluronic acid (HA), mimicking the natural lubricin-HA complex. HAPA and MXene nanosheets were incorporated into polyvinyl alcohol (PVA) hydrogel and physically interlocked within porous polyetheretherketone (PEEK) via freeze-thaw cycles to form a cartilage-inspired composite (PVA/HAPA/MXene-PEEK). The composite exhibited a high water content of 83.0% and characteristic biphasic lubrication behavior. Moreover, it exhibited exceptional lubricating performance against various counterface materials, reducing the coefficient of friction with TC4 to as low as 0.033. This improvement is attributed to the hydration layer provided by HAPA and the potential interfacial lubrication contribution of MXene. The composite further showed good cytocompatibility. Overall, this design offers a promising biomimetic strategy for improving lubrication in MTP joint prostheses, while noting that direct evidence of MXene transfer and antibacterial activity warrants future investigation.