Injured cartilage does not repair itself well. These injuries can develop into the most common form of arthritis, osteoarthritis, in which cartilage within a joint breaks down and causes pain and stiffness. Surgical procedures often fail to completely restore cartilage tissue function.

As an alternative, cartilage-like, biodegradable tissue can attach to cartilage and repair it. However, producing a material that integrates properly with the cartilage has proved difficult. Many existing types of engineered cartilage must be secured with sutures or glue, but true integration requires the engineered tissue to bond with the extracellular matrix of the cartilage.

Paul et al. developed a biocompatible, photo-curable material made of GelMA-glycol chitosan hydrogels that adheres strongly to cartilage. The material is crosslinked in place, which completely fills in an injury and allows covalent binding with proteins in the cartilage extracellular matrix. The positively charged glycol chitosan is also attracted to negatively charged carbohydrates in the matrix.

“This work shows that the adhesive strength between the bioadhesive and cartilage was substantial initially and improved over time in culture, even under dynamic mechanical loading to simulate joint movement,” said author Travis Klein.

The authors found that cells can grow inside the bioadhesive to produce more cartilage matrix, which will help with the regeneration of injured tissue. The material’s performance suggests it may be a suitable alternative to existing clinical bioadhesives for repairing cartilage injuries.

To further explore the potential of these bioadhesive hydrogels for cartilage repair and regeneration, the authors plan to carry out in vivo studies to learn how this bioadhesive repairs cartilage defects and withstands physiological loading in a living organism.

Source: “GelMA-glycol chitosan hydrogels for cartilage regeneration: The role of uniaxial mechanical stimulation in enhancing mechanical, adhesive, and biochemical properties,” by Sattwikesh Paul, Karsten Schrobback, Phong Anh Tran, Christoph Meinert, Jordan William Davern, Angus Weekes, Udhaya Nedunchezhiyan, and Travis Jacob Klein, APL Bioengineering (2023). The article can be accessed at