A self-replenishing biocompatible hydrogel having a zwitterionic polymer embedded throughout the matrix system to act as a lubricant and a surface modified with the same zwitterionic polymer. When surface material loss occurs in the hydrogel, such as a surface crack or a scratch, the damage propagates through the matrix rupturing the pockets of lubricant. The zwitterionic polymer is then drawn into the site due to the change in entropy at the surface and the positive and negative charge groups of the side chains fuse across the damage cite due to strong electrostatic attraction causing inter-chain association.