Innovating Lubrication with Polyelectrolyte Hydrogels: Sustained Performance Through Lipid Dynamics

Abstract

The lubrication process of natural joint cartilage involves a series of coordinated mechanisms, a key aspect of which is its ability to continuously extract lubricating components from synovial fluid to achieve sustained lubrication. Inspired by this natural phenomenon, this study reports a novel polyelectrolyte hydrogel, specifically integrating ε-poly-L-lysine (ε-PL), adeptly captures lipids from environment to achieve effective lubrication similar to human joints. The ε-PL within the hydrogel facilitates the dynamic sequestration of lipids, fostering interfacial self-assembly. This setup, enriched with highly hydrated lipid head groups, enhances boundary lubrication capabilities for extended performance. Through rigorous evaluation of friction coefficients and supramolecular interactions between the hydrogel and lipids, it identified hydrogen bonding, charge-dipole, and hydrophobic interactions as key to this self-assembly. The findings affirm the versatility of polyelectrolytes in synthesizing lubricating hydrogels, bridging the gap to the creation of biomimetic hydrogels that mimic natural lubrication with enhanced durability and efficiency.