Chitosan grafted with maleic anhydride and ethylenediamine: Preparation, characterization, computational study, antibacterial and cytotoxic properties

The design and synthesis of chitosan derivatives have been carried out to improve its biological properties, particularly its antimicrobial activity. Thus, this study aimed to obtain the modified chitosan (MC) by grafting maleic anhydride (M-Chitosan) and subsequent reaction with ethylenediamine (EM-Chitosan) to evaluate its bacterial activity. The MC was characterized by elementary analysis, XRD, FTIR, and TG. In addition, the products formed in the chemical reactions were confirmed by computational calculations using the Density Functional Theory (DFT) at level B3LYP/6-31G(d). The antibacterial activity of chitosan and MC was evaluated against Staphylococcus aureus and Escherichia coli, while the cytotoxic potential was tested on normal human fibroblast cells (GM07492A). The antibacterial activity showed that chitosan, M-Chitosan, and EM-Chitosan provided a better inhibitory effect against the Gram-positive strain. In vitro cytotoxicity test showed that the derivatives presented cytotoxicity on GM07492A cells, with great decrease after incorporation of the amino group. Overall, chitosan and its derivatives showed to be promising as biomaterials for pharmaceutical and biomedical applications.