Investigation of the bioactivities of N, N, N-trimethyl chitosan derivatives constructed with sulfonic zwitterionic moieties

Abstract

In this work, a novel class of sulfonic zwitterion-modified quaternary ammonium chitosan derivatives was prepared using N, N, N-trimethyl chitosan (TMCI) as the structural backbone. To verify the successful synthesis, the resulting compounds were comprehensively analyzed in terms of their molecular configurations, thermal behavior, and crystalline properties. Characterization techniques included Fourier-transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (¹H NMR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Antibacterial performance was comprehensively evaluated through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and inhibition rate assessments against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, revealing enhanced antibacterial activity following modification. Antioxidant properties were examined through DPPH, superoxide, and hydroxyl radical scavenging assays, all of which confirmed strong free radical elimination. Furthermore, cytocompatibility tests verified excellent biocompatibility, underscoring their safety for biomedical applications. Collectively, these results highlight the critical role of structural modification in regulating the bioactivity of chitosan-based systems. The multifunctional properties of these derivatives—including potent antimicrobial activity, effective oxidative stress mitigation, and favorable biocompatibility—provide a strong foundation for their potential use in biomedical materials, smart packaging, and preservation technologies.