Novel ionic chitosan derivatives based on pyridinium sulfonate: Synthesis, characterization, and studies on antimicrobial, antioxidant, and biocompatibility properties.

To improve the solubility, antimicrobial efficacy, antioxidant capacity, and biocompatibility of chitosan for broader applications, a series of novel ionic chitosan derivatives were synthesized in this study by amidating chitosan with carboxyl pyridinium sulfonate. These derivatives were characterized through various analytical techniques, including FTIR, H NMR, UV, TGA, and XRD. Proton NMR was particularly utilized to determine the degree of substitution. The modified chitosans showed improved water solubility. Their antimicrobial activity against gram negative E. coli and gram positive S. aureus was evaluated in vitro through inhibition rates, minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC), demonstrating high effectiveness at low concentrations. Additionally, antioxidant tests indicated that these derivatives possess significantly greater antioxidant activities compared to original chitosan, particularly the 5OHNASCS derivative which showed exceptional radical scavenging and reducing capabilities. Furthermore, the CCK-8 assay was employed to assess cytotoxicity in 293 T cells (human embryonic kidney cells), with all samples exhibiting no toxicity. Hemolysis tests were also conducted, revealing that the newly synthesized series of ionic chitosan derivatives showed no hemolytic activity, indicating good biocompatibility and potential for application as wound dressings. In summary, these newly developed ionic chitosan derivatives demonstrated excellent water solubility, antimicrobial activity, antioxidant capacity, and biocompatibility, suggesting their potential use in food and biomedical materials.