Preparation, characterization and antibacterial activities of bio-based schiff base Copper Complex intercalated montmorillonite

The direct use of antimicrobial agents has problems such as high effective dose and short antimicrobial duration. Therefore, encapsulation of antimicrobial agents in nanocontainers can improve stability and antimicrobial efficiency, reduce the risk of drug resistance, and lower the environmental impact. In this study, biomass-based Schiff base ligand (LAE-oVan) was synthesized by condensation of ethyl lauroyl arginate HCl and ortho-vanillin. Bio-based Schiff base copper complex intercalated montmorillonite was then prepared by pretreated montmorillonite (MMT) with Cu 2+ exchange, followed by chelation with LAE-oVan to form antimicrobial nanocomposites (LAE-oVan-Cu@MMT). Release behavior studies have shown that LAE-oVan-Cu@MMT has a release time of up to 2250 min, and the releasable amount of Cu 2+ and LAE-oVan was calculated to be about 35 %. Antibacterial activity was studied by zone of inhibition method, minimum inhibitory concentration method, plate colony counting method and biofilm method. The results showed that LAE-oVan-Cu@MMT achieved 99.99 % antibacterial ratio against Escherichia coli (E. coli) at 25 μg/mL within 1.5 h and Staphylococcus aureus (S. aureus) at 25 μg/mL within 3 h. Biofilms gradually decreased with increasing concentrations of LAE-oVan-Cu@MMT. Moreover, cytotoxicity studies showed that LAE-oVan-Cu@MMT had a low toxicity to L929 cells. This study provides a strategy for the development of novel antimicrobial with low toxic, eco-friendly and long term release efficiency.