Antimicrobial chitosan-based hydrogels: A novel approach to obtain sanitizers

The study presents novel hydrogels obtained by crosslinking chitosan with both furfural and glutaraldehyde via dynamic imine bonds. Scanning electron microscopy confirmed the formation of porous networks with a mean diameter of the pores between 15 and 35 μm, while the supramolecular characterization by polarized optical microscopy and wide-angle X-ray diffraction proved the gelation mechanism. The hydrogels presented great rheological properties, along with an anti-creep behavior. The resulting materials were highly adhesive and had great antioxidant activity, leading to an inhibition of 78 % of DPPH free radicals, and exhibiting antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi, reaching a maximum of the diameter of the inhibition zone of 31 mm against Candida albicans. The MTS assay, performed on NHDF cells confirmed the non-toxicity of the hydrogels, the viability of the cells remaining at values higher than 90 % for all samples, revealing their potential for bioapplications. In vitro release studies of the furfural monoaldehyde showed distinct release kinetics for each hydrogel, emphasizing their versatility. Fitting the data on different mathematical models indicated a diffusion-controlled release mechanism during the entire release process. All these findings highlighted the potential of these hydrogels to be used as biocidal agents for topical applications.