Insights into the interactions between collagen and a naturally derived crosslinker, oxidized chitosan oligosaccharide

Collagen has been widely applied to biomaterials. However, it must be chemically fixed before it can be used. The aim of this work is to study on the crosslinking effect of a naturally derived oxidized chitosan oligosaccharide (OCOS) on collagen type I. The physicochemical properties and biocompatibility of the crosslinked collagen (OCOS-Col) were evaluated. The FTIR spectroscopy showed that crosslinking via OCOS had no impact on the structural integrity of collagen. DSC and TG tests showed that the thermal stability of crosslinked collagen was improved significantly, while the crosslinking density test indicated that the amino groups of collagen could predominantly react with the available aldehyde groups of OCOS. The mechanical properties, hydrophilicity, and enzymatic degradation test showed that the crosslinked material had improved properties. However, the porosity test showed that the crosslinked material was more compact, which was consistent with the AFM observation that crosslinked collagen revealed a denser network structure. Cytotoxicity test showed that the crosslinked collagen was conducive to cell adhesion, growth, and proliferation. In conclusion, this work reveals that OCOS stabilized collagen as a crosslinker, preserved its triple helical structure, and reserved its good biocompatibility. OCOS was proven to be a safe and reliable crosslinker for collagen. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48489.