Synthesis of N-isonicotinic sulfonate chitosan and its antibiofilm activity against E. coli and S. aureus

N -(sodium 2-hydroxypropylsulfonate) chitosan (HSCS), N -sulfonate chitosan (SCS) and N -isonicotinic sulfonate chitosan (ISCS) were prepared. The structures of the prepared chitosan derivatives were characterized by nuclear magnetic resonance ( 1 H NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy and elemental analysis (EA). Antibacterial and antibiofilm activities of these chitosan derivatives were evaluated in vitro . The minimum inhibitory concentration (MIC) of HSCS and SCS against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) were 0.625 mg/mL and 0.156 mg/mL, respectively. ISCS exhibited MIC values of 0.313 mg/mL and 0.078 mg/mL against E. coli and S. aureus , respectively. ISCS demonstrated superior antibacterial and antibiofilm properties compared to SCS and HSCS. These findings suggest that the incorporation of a pyridine structure into sulfonate chitosan enhances its antibacterial and antibiofilm activities, and the prepared ISCS has a promising application prospect for controlling the reproduction of microorganisms in the field of food packaging.