|Name||Mr. Ziyang Huang|
|Organization or Institution||university of central florida|
Antimicrobial Magnesium Hydroxide Nanoparticles as an Alternative to Cu Biocide for Crop protection
Ziyang Huang1,2, Parthiban Rajasekaran2, Ali Ozcan1,2 and Swadeshmukul Santra1,2,3,4
1Department of Chemistry, 2NanoScience Technology Center, 3Department of Materials Science and Engineering, 4Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826.
Plant disease contributes to 10-16% of global harvest loss thus limiting food supply. Copper (Cu) based bactericides/fungicides are extensively applied to control a broad spectrum of crop diseases. Prolonged use of Cu biocides increases the risk of development of Cu resistance and their accumulation in soil. There is a strong need to develop Cu alternatives. Low cost, abundant and environmental friendly magnesium hydroxide (Mg(OH)2) has been suggested has antimicrobial activity at certain concentrations. In this study, Mg(OH)2 nanoparticles (NPs) were synthesized through alkaline precipitation method. In addition, water-soluble citrate or betaine was used as a capping agent to control particle size, surface charge, and to prevent particles aggregation. X-ray diffraction results showed all as-synthesized Mg(OH)2 NPs were brucite Mg(OH)2. The morphology of as-prepared Mg(OH)2 were observed through Scanning electron microscopy and transition electron microscopy. Electron microscopy study confirmed the formation of ~10 nm size cubical NPs with citrate and ~ 100 nm size lamellar NPs with betaine. When screened for antimicrobial properties, as-prepared Mg(OH)2 particles showed enhanced antimicrobial properties against model plant pathogens such as Xanthomonas alfalfae, Pseudomonas syringae, and Escherichia coli. In bacterial killing (CFU) assay, as-prepared Mg(OH)2 NPs exhibited bacterial growth inhibition as early as 4 hours and by 24 hours post-treatment. Phytotoxicity studies on tomato plants indicated as-prepared Mg(OH)2 NPs caused very little tomato plant tissue injury compared to Cu products. Thus, Mg(OH)2 NPs synthesized by our method present themselves as potential Cu alternative biocides for crop protection.