Solar energy driven photo catalytic action and antimicrobial activities of Iron oxide nanoparticles

Every year loss of crop yield (at least 20-40%) occurs by pathogenic infections that leads to loss of billions of dollars worldwide. Usage of antibiotics are limited in numerous countries for controlling bacterial diseases / infections in agricultural field. Therefore, alternative protocol is necessary to combat with microbial pathogens and to overcome the requirement to suppress use of conventional antibiotics in plant production. Nanoparticles (NPs) having antimicrobial properties can have potential to combat the bacteria and can protect the plant / crop production. Moreover, such NPs may also have potential to suppress the plant pathogens. Sol-gel method is used for synthesis of iron oxide NPs with variation in pH (1, 2, 3, 4, 5, 6, 7, 8 and 9). Magnetic field annealing (MFA) of NPs at different temperatures (200 and 300 degrees C) is done. 300 degrees C MFA samples show efficient results. X-ray Diffraction (XRD) results show magnetite phase (at pH 1, 2 and 6), mixed phases (i.e. hematite and maghemite) at pH 3-5, maghemite phase (at pH 7-8) and hematite phase (at pH 9) of iron oxide. Scanning Electron Microscopy (SEM) analysis shows particle size of similar to 50 nm for MFA iron oxide NPs (at pH 6). Raman spectroscopy results show the formation of iron oxide NPs. Furthermore, 300 degrees C MFA magnetite nanoparticles (at pH 6) proved to be potential candidate against bacteria (E. coli with inhibition zone similar to 31 mm) and against methylene blue with enhanced photo catalytic action. In-vitro activity of magnetite NPs expressively inhibited the growth of Fusarium oxysporum after 3rd and 7th day of incubation in a dose-dependent way. In-vivo studies also exhibited improved plant growth parameters after treatment with different concentrations of magnetite NPs. This work suggests that iron oxide NPs can be used in agricultural sector for protection of plant. [GRAPHICS] .

Automated summary

Crop yield loss due to pathogenic infections costs billions of dollars annually. The use of antibiotics in agriculture is limited, necessitating the development of alternative protocols to combat microbial pathogens. Nanoparticles with antimicrobial properties, such as iron oxide, show potential in protecting plant/crop production and suppressing plant pathogens. This study synthesized iron oxide nanoparticles using the sol-gel method and magnetic field annealing, and demonstrated their efficacy in inhibiting bacterial growth and enhancing photocatalytic activity. In vitro and in vivo experiments also revealed improved plant growth parameters after treatment with iron oxide nanoparticles.