Abstract

Degenerative diseases like osteoarthritis (OA) affect millions of people worldwide. This wear-and-tear type disease affects an ever-increasing number of people, and the few treatments out there show minimal effectiveness. Hybrid hydrogels are promising in tissue engineering applications as scaffolds for supporting native cartilage damaged from OA. Such gels can be designed and synthesized to be biocompatible and have outstanding mechanical properties, approaching the remarkable behavior associated with native articular cartilage. However, many of these tough hybrid hydrogel scaffolds lack the potential for tissue regeneration. Our work focuses on developing and modifying tough poly(acrylamide-co-acrylic acid)/alginate hybrid hydrogel networks for cartilage repair. Different variations of hydrogel scaffolds were synthesized to closely mimic native cartilage tissue. These hydrogel scaffolds were characterized mechanically (i.e., compression, tension, resilience). Modifications to the network were performed (i.e., sulfation). By varying the composition of the hydrogels, the mechanical properties can be finely tuned. Furthermore, mechanical testing showed that our modified hybrid hydrogels can achieve a comparable compressive stiffness (>200 kPa) to that of native articular cartilage tissue. Interestingly, cyclical mechanical testing revealed the network's resilience and remarkable toughness. These results suggest that the hydrogel scaffolds have potential as tough cartilage mimics and further support their investigation in vitro. Furthermore, alternative networks are being developed to surpass the capabilities of the current hybrid hydrogel networks.

Key Points

• Modified hybrid hydrogels achieve compressive stiffness over 200 kPa, comparable to native cartilage.
• Characterization revealed outstanding mechanical properties and toughness, indicating potential for tissue mimics.
• Developments include variations in composition and sulfation alterations to enhance hydrogel networks.
• Research highlights the need for further in vitro investigations to validate effectiveness in cartilage repair.