Preparation, characterisation and antibacterial activity evaluation of N-acetylneuraminic acid-crosslinked chitosan hydrogels

In this study, CS-NeuAc hydrogel was prepared from chitosan (CS) and N-acetylneuraminic acid (NeuAc) using cyclic freeze/thaw under 1-ethyl-3-(3-dimethylaminopropyl)-carbodiiminde/N-hydroxysuccinimide catalysis. Fourier transformed infrared spectroscopy, X-ray diffraction, and scanning electron microscopy analyses confirmed the successful synthesis of CS-NeuAc hydrogel. CS-NeuAc hydrogels were found to be equipped with suitable swelling behaviour, porosity, water evaporation rate, degradation rate, and good mechanical properties compared to CS. The swelling rate, water evaporation rate, and degradation rate of prepared hydrogel with a CS/NeuAc molar ratio of 10:1 were 710.7 ± 28.6%, 78.2 ± 1.6%, and 58.6 ± 1.5%, respectively. Moreover, CS-NeuAc hydrogel exhibited excellent biocompatibility. The evaluation of CS-NeuAc hydrogels’ antibacterial activity confirmed that they serve as effective antibacterial materials against Escherichia coli and Staphylococcus aureus with antibacterial rates above 95% and 92%, respectively, and the minimum inhibitory concentrations was above 400 μg/ml. In conclusion, CS-NeuAc hydrogel can be a candidate for biological antibacterial materials. [Display omitted] •Novel CS-NeuAc hydrogels were prepared from chitosan and N-acetylneuraminic acid.•CS-NeuAc hydrogel exhibited a three-dimensional pore network structure distributed uniformly.•CS-NeuAc hydrogels could be well evaluated by the Schott second-order kinetic model.•The CS-NeuAc hydrogel had good antibacterial property against E. coli and S. aureus.