Rational design of biocompatible IPNs hydrogels containing carboxymethyl starch and trimethyl chitosan chloride with high antibacterial activity

Antimicrobial hydrogels have enticed a major concern for repairing soft tissues, particularly prohibiting bacterial infections that are frequently accompanied by impaired wound healing. Nevertheless, the development of new antibacterial hydrogel ingrained with excellent cell affinity is one of the robust challenges. This study aims for the first time to design a new class of antibacterial hydrogels with high biocompatibility through the formation of a water-soluble polyelectrolyte complex by performing a physical crosslinking reaction between the cationic trimethyl chitosan chloride (TMC) and anionic carboxymethyl starch (CMS) polymers. The structure of as-prepared hydrogels was characterized using different spectral and surface techniques including FTIR, ¹H-NMR, SEM, and XRD. The data stated that the hydrogels prepared with a high TMC content possess a high surface area and small pore size compared to other samples, suggesting more occurred interactions with CMS chains. Then, the antibacterial activity was investigated against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as two pathogenic bacteria. The as-developed hydrogel with a high TMC mass achieved superior inhibition zones with diameters of 26 and 24 mm for E. coli and S. aureus, respectively, compared to that of pure TMC (20, and 18 mm). Moreover, the cytotoxicity of the hydrogels was examined against two normal cell lines such as VERO and lung (Wi38) cells lines. The cell viability of hydrogel was recorded 100% up to concentrations lower than 62.5, and 125 μg/mL for normal lung and VERO cell lines, respectively.