Antibacterial Chitosan-based Semi-IPN Hydrogels

In order to obtain semi-IPN hydrogels with antibacterial properties, three types of chitosan were used: commercial chitosan (CC, Sigma-Aldrich St Louis, MO, USA, ≥75% deacetylation degree, Mn = 2.056 × 10⁵ g/mol), chitosan synthesized in previous works from commercial chitin via a deacetylation process (CCH, 77% deacetylation degree, Mn = 4.7291 × 10⁵ g/mol [52 (link)]) and mineral-enriched chitosan extracted in previous works from shrimp shells (SHC, 76% deacetylation degree, Mn = 9.058 × 10³ g/mol, crystallinity 59.42% on (020) plane [52 (link)]). Vinyl benzyl trimethylammonium chloride (Sigma-Aldrich, 99%, VBTAC) was used as a monomer to generate quaternary ammonium pendant groups. The synthesis of semi-IPN hydrogels was performed following the initiation process with 4,4′-azobis-4-cyanovaleric acid (Sigma-Aldrich ≥ 98%, ACVA) in the presence of N,N′-methylenebisacrylamide (Sigma Aldrich ≥ 98%, MBA) as a crosslinking agent. The listed compounds were used without any purification. Acetic acid (Sigma-Aldrich, 99%) and pure demineralized water were also used to solubilize chitosan.