Purpose: The purpose of this study was to evaluate different engineering methods for production of CN to enhance its antimicrobial activity, which will help optimize the potential for further application of these particles.
Methods: CN was prepared in solution using different molecular weights of chitosan, cross linkers (sodium sulfate or tripolyphosphate) and sonication conditions. The size of CN was measured using a nanoparticle analyzer. The antimicrobial activity of CN was assessed against E. coli O157:H7 to determine the optimal conditions for chitosan nanoparticle generation with high antimicrobial properties.
Results: It was observed that CN with a size smaller than 150 nm exerted better antimicrobial activity. In addition, the selection of sodium sulfate as a crosslinker over sodium tripolyphosphate achieved better results, as most bacteria were killed after 4 h and no regrowth was observed after 24 h. For sonication power, 60 W enhanced the antimicrobial activity compared with 96 W. The best engineering conditions that enhanced antimicrobial activity included a combination of low molecular weight chitosan with sodium sulfate as cross-linking agent at a final concentration of 0.4-0.6 %.
Significance: The optimized engineering of CN particles may be applied in future studies to assess their applicability in different fields, such as animal disease treatment as well as elimination of other pathogens from food and the environment.