The effects of chemical crosslinking manners on the physical properties and biocompatibility of collagen type I/hyaluronic acid composite hydrogels

It is necessary to use chemical crosslinking to regulate the mechanical properties, biodegradability and biocompatibility of hydrogels. In this study, three kinds of collagen type I (Col I)/hyaluronic acid (HA) hydrogels with the same ratio and different chemical crosslinking manners were designed and fabricated, and the effects of chemical crosslinking manners on the physical properties and biocompatibility of hydrogels were investigated. The gelation time, mechanical property, swelling and degradability of hydrogels were characterized. Chondrocytes were encapsulated into these hydrogels to detect their effects on cell survival, proliferation, morphology and ECM secretion. Furthermore, the hydrogels were implanted into the back of SD rats to evaluate their biodegradability and biocompatibility in vivo. The results showed that chemical crosslinking manners of hydrogels could affect their physical properties to some extent. Chondrocytes encapsulated into these hydrogels showed a round or oval shape. ECM secretion of cells encapsulated in hydrogels increased with the elongation of culture duration, and cells encapsulated in hydrogels HA-sNHS/Col I (HSC) and HA-CHO/Col I (HCC) secreted more ECM than others. In vivo studies demonstrated that these hydrogels showed similar and acceptable inflammatory reaction.