In Situ Growth of Silver Nanoparticles into Reducing-End Carbohydrate-Based Supramolecular Hydrogels for Antimicrobial Applications.

Hydrogels with antibacterial activities have the potential for many biomedical applications, such as wound healing, because of their capacity to maintain a moist environment and prevent infections. In this work, an ultrasound-induced supramolecular hydrogel consisting of easily accessible reducing-end-free glucosaminylbarbiturate-based hydrogelators that serve the in situ fabrication of silver nanoparticles (AgNPs), excluding the addition of any external reducing or stabilizing agents, has been developed. The innovative synthetic approach relied on the use of N,N'-disubstituted barbituric acid derivatives as a versatile chemical platform that site-selectively reacted with the amino function of glucosamine. A series of glucosaminylbarbiturate were synthesized, and we identified one carbohydrate-based hydrogelator that produced a thixotropic supramolecular hydrogel after ultrasound-mediated breaking of an intralocked hydrogen bond. AgNPs@hydrogels were prepared through in situ reduction of silver ions mediated by the reducing properties of carbohydrates. The AgNPs@hydrogel composite revealed good antimicrobial properties toward both Gram-positive and Gram-negative bacteria. These findings contribute to the development of carbohydrate-based supramolecular hydrogels and make them promising efficient and safe soft materials for antimicrobial therapy.