Polyelectrolyte-Functionalized NanoMOFs for Highly Efficient Aqueous Lubrication and Sustained Drug Release.

This study demonstrates the hybridization of polyelectrolyte brushes with anti-inflammatory drug-loaded nanoMOFs that can achieve highly efficient aqueous lubrication and sustained drug release for the synergistic therapy of osteoarthritis (OA). Poly(3-sulfopropyl methacrylate potassium salt) (PSPMK) brushes are grown on the surface of the UiO-66-NH2 via one-pot grafting polymerization, which served as a general surface modification method of NH2 -MOFs to grow the polymer brushes. The growth of the PSPMK brushes greatly enhance the stability, dispersity, and swollen property of the AS-UiO-66-NH2@PSPMK in aqueous media. Using as lubricating additives, the UiO-66-NH2 @PSPMK achieves not only reductions in both coefficient of friction and wear volume over 70% and 99% but also supports high load-carrying capacity and long-term durability. The PSPMK brushes can be served as an universal interfacial modification soft layer that can significantly improve the aqueous lubricating performance of other types of NH2 -MOFs. After encapsulating the anti-inflammatory aspirin (AS), the AS-UiO-66-NH2 @PSPMK shows both sustained drug release and good biocompatibility toward the human normal chondrocytes. This work establishes anti-inflammatory drug-loaded UiO-66-NH2 @PSPMK as a potential multifunctional joint lubricant for OA treatment.