Impact of Crosslinking Degree on Chitosan and Oxidized Guar Gum-Based Injectable Hydrogels for Biomedical Applications

Evaluating the biodegradability and biocompatibility of hydrogels is essential for identifying materials suitable for biomedical applications. This study describes the fabrication of hydrogels utilizing physiological-soluble chitosan (N-succinyl chitosan, NSC) crosslinked with dialdehyde guar gum (Oxidized Galactomannan, OxGM) via the Schiff-base reaction. Hydrogels with varying volumetric ratios of NSC/OxGM, resulting in distinct NH2/CHO functional group ratios and crosslinking degrees, underwent comprehensive characterization using Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), swelling, and scanning electron microscopy (SEM). Gelation time (tgel) is assessed by rheological analysis (tgel = G ' > G ''), where tgel increased with higher crosslinking density, reaching a maximum value of approximate to 80 s. Biodegradation analysis in phosphate-buffered saline (PBS) with lysozyme (13 mg L-1) revealed that the crosslinking degree significantly influenced degradation, with lower crosslinking associated with an elevated degradation profile. Moreover, cell viability assays with fibroblastic cells demonstrated minimal cytotoxicity, but an increase in free aldehyde groups correlated with decreased cell viability. For the 75C25C hydrogel, the compressive test yielded a Young's modulus value of 67.2 kPa (+/- 8.5). These results imply that the hydrogels developed exhibit favorable biodegradability and biocompatibility, making them promising candidates for diverse biomedical applications.