Cartilage-mimetic hydrogels with multifunctions from grape seed protein and chitosan

Designing hydrogels with antibacterial, antifouling, lubricating, wet-adhesive, and highly mechanical properties is crucial for articular cartilage replacement. However, achieving such a combination remains a big challenge. To tackle this issue, a PCG matrix with a compressive strength of 42 MPa was prepared from polyvinyl alcohol, grape seed protein and chitosan via the multiple linkages (crystalline domains, hydrogen bonds, and ionic interactions). Next, the introduction of sulfobetaine methacrylate in the top layer endowed the hydrogel antifouling and lubricating performances. Subsequently, ciprofloxacin (CIP) was encapsulated via the self-assembly of soybean lecithin (SL) in water using the thin-film hydration method, followed by soaking the pre-hydrogel into the aqueous dispersion. Compared with PCG hydrogel, the antibacterial effects on E. coli and S. aureus were increased by 2250% and 1700% respectively. Meanwhile, the SPA gel achieved antibacterial rate of ~100% against both types of bacteria. In addition, the hydrophilic phosphatidylcholine groups of SL formed a boundary lubrication layer, reducing the coefficient of friction to 0.018. Finally, a gelatin-tannic acid adhesive layer was coated on the bottom to obtain the resultant SPA gel. The amino acids and polyphenol groups endowed the hydrogel with robust wet adhesion. Owing to the biocompatible materials and green process, the obtained SPA hydrogel had a cell viability of 96.7%, indicating excellent cytocompatibility. This biomimetic design successfully replicated the structures and performances of articular cartilages, making it promising for cartilage replacements.