Revisiting the Classical Multicomponent Hantzsch Reaction to Form Fluorescent Dextran Hydrogels with Antibacterial Activity

There has been considerable interest in developing hydrogels derived from natural polysaccharides that combine controllable luminescent properties, enhanced functionality, and inherent biocompatibility. Herein, the classical multicomponent Hantzsch reaction was explored to fabricate luminescent dextran-based hydrogels with antibacterial activity. This reaction facilitates the formation of 1,4-dihydropyridine (DHP) derivatives from cross-linking of acetoacetylated dextran, aldehyde, and NH4OAc. Both low molecular weight aldehydes (formaldehyde and glutaraldehyde) and polyaldehyde (oxidized dextran) have been successfully applied in the Hantzsch cross-linking strategy, resulting in a series of intrinsically luminescent hydrogels (DHPD) with tunable gelation kinetic, mechanical properties, and operating windows. The DHPD hydrogels exhibited superior antibacterial activity, achieving an antimicrobial rate of over 90% against Gram-negative bacteria (Escherichia coli). Notably, significantly promoted wound healing and anti-inflammation effects were achieved in E. coli-infected wound models by the DHPD-F2 hydrogel dressing. Therefore, the Hantzsch cross-linking strategy provides a robust platform for the fabrication of photoluminescent dextran hydrogels, offering promising potential for advanced antibacterial wound dressing applications.