<i>In Situ</i> Growth of Silver Nanoparticles\ninto Reducing-End Carbohydrate-Based Supramolecular Hydrogels for\nAntimicrobial Applications

Hydrogels with antibacterial activities have the potential\nfor\nmany biomedical applications, such as wound healing, because of their\ncapacity to maintain a moist environment and prevent infections. In\nthis work, an ultrasound-induced supramolecular hydrogel consisting\nof easily accessible reducing-end-free glucosaminylbarbiturate-based\nhydrogelators that serve the <i>in situ</i> fabrication\nof silver nanoparticles (AgNPs), excluding the addition of any external\nreducing or stabilizing agents, has been developed. The innovative\nsynthetic approach relied on the use of <i>N,N′</i>-disubstituted barbituric acid derivatives as a versatile chemical\nplatform that site-selectively reacted with the amino function of\nglucosamine. A series of glucosaminylbarbiturate were synthesized,\nand we identified one carbohydrate-based hydrogelator that produced\na thixotropic supramolecular hydrogel after ultrasound-mediated breaking\nof an intralocked hydrogen bond. AgNPs@hydrogels were prepared through <i>in situ</i> reduction of silver ions mediated by the reducing\nproperties of carbohydrates. The AgNPs@hydrogel composite revealed\ngood antimicrobial properties toward both Gram-positive and Gram-negative\nbacteria. These findings contribute to the development of carbohydrate-based\nsupramolecular hydrogels and make them promising efficient and safe\nsoft materials for antimicrobial therapy.