Injectable self-crosslinking hydrogels for meniscal repair: A study with oxidized alginate and gelatin

Injectable in situ gelling hydrogels are viable treatment options for meniscal injuries occurring in athletes. The present study aims to develop an injectable hydrogel via borax complexation of oxidized alginate, followed by a self-crosslinking reaction with gelatin through a Schiff's base reaction. Gelation kinetics and degree of crosslinking could be controlled by changing the concentration of components and the formation of Schiff ;'s base formation was confirmed by Raman spectroscopy. The injectable alginate dialdehyde-gelatin (15ADA20G) hydrogel showed 423 ± 20 % water uptake, had an average pore size of 48 μm and compressive strength 295 ± 32 kPa. Phase contrast images, scanning electron micrographs and actin staining depicted adhesion, profuse proliferation, and distribution of fibrochondrocytes on the hydrogel demonstrating its cytocompatibility. Application of hydrogel at the pig meniscal tear ex vivo showed good integration with the host meniscal tissue. Further, the histology of 15ADA20G hydrogel filled meniscus showed retention of hydrogel in the close proximity of meniscal tear even after 3days in culture. The self-crosslinking injectable hydrogel offers a niche for the growth of fibrochondrocytes.