Facile room-temperature one-pot synthesis of a gold nanoparticle-embedded hydrogel for recyclable dye degradation and antimicrobial applications

Abstract

This work reports a sustainable and equipment-free one-pot strategy for the synthesis of gold nanoparticles (Au NPs) embedded within a hydrogel matrix at room temperature. In this method, Au NPs are formed in situ through simple mixing of aqueous sodium alginate (Alg, 3 wt%), citric acid (CA, 0.5 M), and chloroauric acid (0.5 mM), where CA serves a dual role as both crosslinker and a reducing agent. The resulting hydrogel exhibits excellent catalytic activity toward the reductive degradation of organic dyes, achieving rapid decolorization efficiencies of 91% for Congo red and 97% for methylene blue within 5 min in the presence of sodium borohydride while maintaining reusability over five cycles. Besides, the material also effectively degrades real wastewater samples from the textile industry, highlighting its potential for sustainable wastewater treatment applications. Additionally, the material exhibits potent antibacterial activity against Staphylococcus aureus, Escherichia coli, and Acinetobacter baumannii. This activity is attributed to reactive oxygen species (ROS)-mediated membrane disruption, and the sustained release of Au NPs from the hydrogel matrix. This simple one-pot synthesis strategy highlights significant potential for biomedical application and environmental remediation, especially in resource-limited settings.