Bacterial cellulose-based hydrogels carrying Lewis X trisaccharides as a system for monitoring carbohydrate–carbohydrate interactions with the naked eye

Bacterial cellulose-based hydrogels carrying Lewis X trisaccharides were prepared via a three-step synthetic route, involving (1) NaIO₄ oxidation of commercially available <i>nata de coco</i>, (2) reductive amination of the product using propargylamine, and (3) Cu⁺-catalysed alkyne-azide cycloaddition using azide-functionalised Lewis X trisaccharides. The resultant bacterial cellulose-based hydrogels were assembled in aqueous media containing Ca²⁺ or Na⁺, demonstrating ion-mediated interactions among Lewis X trisaccharides. Furthermore, reference experiments using bacterial cellulose-based hydrogels carrying <i>N</i>-acetyl-lactosaminides and those carrying <i>N</i>-acetyl-D-glucosaminides revealed that the two non-reducing terminals (i.e., β-galactoside and α-fucoside of Lewis X trisaccharide) substantially contribute to their interactions.