Microwave synthesis of graphene oxide decorated with silver nanoparticles for slow-release antibacterial hydrogel

Inorganic antibacterial materials, graphene oxide (GO), and silver nanoparticles (AgNPs) are considered promising antibacterial materials due to their excellent biocompatibility, broad-spectrum antibacterial properties, and non-drug resistance. In this manuscript, Branched polyethyleneimine (PEI) stabilized GO-AgNPs antibacterial nanocomposites (PEI-GO-AgNPs) were integrated with Pluronic F127 to develop a slow-release antibacterial hydrogel for more stable and sustained antibacterial effect. Antibacterial mechanism has been proposed according to the experimental observation. The synergistic effect of PEI-GO-AgNPs resulted in the death of bacteria and molds. PEI reduced the aggregation of PEI-GO-AgNPs nanomaterials to capture/adsorb pathogens effectively and increased the contact between Ag and pathogens. The sharp edges of the GO nanosheets can physically cut the bacterial cells then the Ag can interact with the cell membrane, disrupting the permeability and material transport of the cell membrane. The antibacterial test showed that the antibacterial rate of 10 μg/mL PEI-GO-AgNPs against bacteria (Escherichia coli) and molds (Candida albicans) are 99.86% and 99.94%. It is worth to mention that the PEI-GO-AgNPs were well dispersed in normal saline within a week. In addition, PEI-GO-AgNPs released 72% Ag from the prepared Pluronic F127 hydrogel within one week.