A Regenerative Hydrogel Coating

ABSTRACT Synthetic materials decorated with hydrogel coatings can accommodate the requirements of biological tissues for biocompatibility, lubricity, and flexibility. Nevertheless, these features may be subject to deterioration under long‐term severe friction conditions. Inspired by Ambystoma mexicanum , a regenerative hydrogel coating to circumventing existing notions of wear resistance is presented, which can maintain a long‐term lubricated and soft surface through the utilization of increment substances under abiotic mechanisms. The term regenerative refers to a process of directional differentiation without the use of external raw materials, whereby a hydrophobic plastic (PDHEA) is transformed into a hydrophilic hydrogel (PHEA) coating in response to external stimulation. Such a regenerative hydrogel coating can not only be repaired after local wear and reborn after full wear, but also be adjusted with the thickness and mechanical properties according to specific engineering requirements during differentiation. Furthermore, the regenerative hydrogel coating is applied for the surgery of artificial cartilage, with potential clinical applications such as long‐acting protection of bone tissue.