Biomimetic pore-throat engineered ultrahigh molecular weight polyethylene with sustained tea polyphenol release for infection-resistant joint implant material.

To address the limitations of systemic antibiotics in treating prosthetic joint infections (PJI), ultrahigh molecular weight polyethylene (UHMWPE)-based polyphenol delivery systems have been developed as an antibiotic-free strategy. However, challenges exist in achieving sustained antimicrobial efficacy and enhancing overall performance. To achieve threshold-insensitive sustained release, a biomimetic pore-throat structure inspired by geologic capillary transport mechanisms was engineered within UHMWPE. This structure was constructed through strategic co-incorporation of polyethylene oxide (PEO) and a sub-permeation-threshold tea polyphenol (epigallocatechin gallate, EGCG as representative). PEO-encapsulated EGCG clusters formed expanded pore-throat networks with enhanced distribution uniformity, facilitated by hydrogen bonding between PEO's ether groups and EGCG's phenolic hydroxyls. This microstructure enabled swelling-regulated drug release obeying Korsmeyer-Peppas kinetics. The PEO concentration directly modulated sustained EGCG release through capillary action and swelling-erosion. The resulting composites achieved > 80 % antibacterial efficacy against major pathogens while PEO simultaneously formed boundary-hydrated lubrication layers that reduced the friction coefficient to 0.065. Combined with favorable biocompatibility and effective suppression of bacterial-induced inflammation, this biomimetic strategy establishes a material-level, proof-of-concept approach with potential for future development toward infection-resistant orthopedic devices.