Enhanced Lubrication through Porous Hydrogels Anchored with Hyaluronic Acid

Achieving sustained low-friction in hydrogels is often hindered by poor retention of boundary lubricants like hyaluronic acid (HA). Here, we report a multiphase hydrogel designed to actively manage HA lubrication. We fabricated a porous poly(vinyl alcohol) (PVA) hydrogel matrix containing polycationic chitosan quaternary ammonium salts (PQCS). This interconnected porous architecture serves a dual role: it acts as a reservoir for HA, while the PQCS provides electrostatic anchoring sites to control HA retention and release. Under load, this structure facilitates the extrusion of anchored HA to the sliding interface, establishing a continuous and self-replenishing boundary lubrication layer. Consequently, the hydrogel anchored with high-molecular-weight HA achieved a sustained and low coefficient of friction (COF < 0.05) in PBS solution. This strategy of engineering internal architecture to control lubricant dynamics at the interface offers a promising approach for designing advanced self-lubricating biomaterials like artificial cartilage.