Construction of a cross-bedded tea polyphenol delivery structure in ultrahigh molecular weight polyethylene against bacteria for joint replacement

Abstract

The high jeopardy of prosthesis joint infection demands urgent development of an in-situ drug delivery joint material, while achieving sustained antimicrobial activity remains a challenge. Herein, a sedimentary rock-like “cross-bedded” drug delivery structure was constructed in the ultrahigh molecular weight polyethylene (UHMWPE) joint material. Epigallocatechin gallate (EGCG), a representative tea polyphenol, was employed as a substitute of antibiotics with antimicrobial activity. Delivery pathways composed of EGCG were highly aligned and cross-bedded with the UHMWPE matrix under the strong flow field offered by solid-state extrusion. The EGCG pathlength was thus increased in a longitudinal section, attenuating burst release and prolonging the release time of EGCG. The release of EGCG in the “cross-bedded” structure was restricted to a low concentration at the initial stage yet subsequently extended 2–3 times compared to that in the massive structure. The prolonged release ratio is nearly equivalent to the EGCG pathlength increment as calculated via a simplified mathematical model. The quantitative relationships between release behavior and antimicrobial performance proved that the cross-bedded structure was efficient in maintaining sustained antimicrobial activity. These findings offer a paradigm to achieve sustained drug therapy in UHMWPE joint material, which is constructive for treating prosthetic bacterial infections in clinical trials.