Work

Chitin and cellulose nanomaterials sulfation by mechanochemistry

Year: 2025

Type: article

Abstract: Natural sulfated polysaccharides (NSP) are widely used in food, medical, and cosmetic applications. Chemical sulfation is typically required to mimic NSP properties, but it often involves toxic solvents, excess reagents, and long heating times. We report for the first time the sulfation of well-defined cellulose and (oxidized)-chitin nanomaterials by mechanochemistry using a sulfur trioxide–pyridine complex offering a greener alternative. In contrast to their unmodified counterparts, the sulfated compounds S-NanoCel, S-NanoChit, and SO NanoChit exhibited significantly lower turbidity values of 25, 45, and 158 NTU, respectively, confirming their excellent water dispersibility. The presence of covalently bound sulfate groups was confirmed by FTIR spectroscopy with characteristic bands near 1250 and 820 cm⁻¹ and 13C NMR. Elemental analysis revealed degrees of substitution (DS) between 0.22 and 0.78, with S-NanoCel showing the highest DS. X-ray diffraction showed that the unmodified nanomaterials had crystallinity values ranging from 80 to 93 %. After sulfation, the crystallinity was reduced and is no longer quantifiable, although the overall crystalline structure remained visible, with lattice arrangements corresponding to the alignment of the polysaccharide chains. Finally, biological evaluation demonstrated that sulfated oxidized chitin exhibited the strongest heparanase inhibitory activity (IC₅₀ = 0.7 µg·mL⁻¹), suggesting its potential as a heparan sulfate analog.

Source: Carbohydrate Polymer Technologies and Applications

DOI: 10.1016/j.carpta.2025.101062