Developing Nano-sanitizers Based on Natural Antimicrobial Materials for Preventing Contamination of Food Products

The Chitosan polymeric backbone may provide a natural safe and biodegradable alternative to antimicrobial chemicals and sanitizing agents for preventing contamination of food products. In this work, we present the first example of covalent attachment of Quercetin molecule, a natural phenolic compound, to Chitosan polymeric scaffold for amplification of the antimicrobial activity. The modified biopolymer has demonstrated amphiphilic characteristics that allow spontaneous self-assemble into nano-sized aggregates beyond certain concentration. The critical aggregation concentration (CAC analysis) showed that the original Chitosan parent polymer undergo self-assembly in concentration of 1.4 mg/mL as calculated using pyrene as a fluorescent probe, while the Quercetin moiety in the new Chitosan polymer has lowered the CAC value to 0.3 mg/mL. The modified Chitosan-based nanoparticles were spectroscopically characterized by multinuclear NMR and FTIR. Their thermal stability was examined using DSC and TGA analyses and compared to the original Chitosan. Gel Permeation Chromatography (GPC) was used to characterize polymer size and biological activity of this new nano-agrochemical material was studied and compared to the non-modified Chitosan.