Synthesis, characterization, and applications of iron oxide nanoparticles.

Objective: The green synthesis method for nanoparticles is getting more attention globally, due to its lesser cost, non-hazardous, and eco-friendly nature. The novelty of the present work is to investigate the anti-bacterial and degradation activity of the green synthesized Iron Oxide NPs. Methods: In this study, the Iron Oxide NPs were synthesized through a green synthesis route from leaves of Ficus Palmata. UV-Vis confirmed Iron Oxide NP's peaks between (230-290 nm), while Fourier transforms infrared spectroscopy analysis showed that several groups were involved in reduction and stabilization. Results: Results indicated that the highest photo thermal activity was shown in light and it was almost 4 folds greater than the control. Similarly, Iron Oxide NPs showed excellent antimicrobial potential against bacterial species "Salmonella typhi" "Xanthomonas Oryzae" and "Lactobacillus" at low concentrations (150 µg/mL). Hemolytic assay results showed that the toxicity was lesser than 5% at both dark and light conditions. Moreover, we also evaluated the photo-catalytic potential of Iron Oxide NPs against methylene orange. Results indicated that almost complete degradation was noted after 90 min in the presence of continuous light. All tests were performed in triplicates. All the data was subjected to P-test (P < 0.5) using Excel and graph pad (V.5.0). Conclusion: Iron Oxide NPs holds a promising future and could be used in treating diseases, and microbial pathogenesis and also could be used as a vector in drug delivery. Moreover, they can also eradicate persistent dyes and could be used as an alternative to remediate pollutants from the environment.

Green Synthesis of Cerium Oxide Nanoparticles (CeO2 NPs) and Their Antimicrobial Applications: A Review.

During the last decade green synthesized cerium oxide nanoparticles (CeO2 NPs) attracted remarkable interest in various fields of science and technology. This review, explores the vast array of biological resources such as plants, microbes, and other biological products being used in synthesis of CeO2 NPs. It also discusses their biosynthetic mechanism, current understandings, and trends in the green synthesis of CeO2 NPs. Novel therapies based on green synthesized CeO2 NPs are illustrated, in particular their antimicrobial potential along with attempts of their mechanistic elucidation. Overall, the main objective of this review is to provide a rational insight of the major accomplishments of CeO2 NPs as novel therapeutics agents for a wide range of microbial pathogens and combating other diseases.

Photo-inactivation of bacteria in hospital effluent via thiolated iron-doped nanoceria.

Hospital wastewater is a major contributor of disease-causing microbes and the emergence of antibiotic resistant bacteria. In this study, thiolated iron-doped nanoceria was synthesised and tested for killing of microbes from hospital effluent. These particles were designed to inhibit the efflux pumps of the bacteria found in hospital effluent with further ability to activate in visible light via iron doping thus generating tunable amount of reactive oxygen species (ROS). The quantum yield of the ROS generated by the nanoceria was 0.67 while the ROS types produced were singlet oxygen (36%), hydroxyl radical (31%) and hydroxyl ions (32%), respectively. The particles were initially synthesised through green route using Foeniculum vulgare seeds extract and were annealed at 200°C and further coated with thiolated chitosan to enhance the solubility and efflux pump inhibition. X-ray diffraction confirmed the polycrystalline nature of nanoparticles and uniform spherical shape with 30 nm size, confirmed by scanning electron microscope. The nanoparticles exhibited 100% bactericidal activity at 100 µg/mL against all the isolated bacteria. The enhanced bactericidal effect of iron-doped nanoceria could be attributed to efflux inhibition via thiolated chitosan as well as the production of ROS upon illumination in visible light, causing oxidative stress against microbes found in hospital effluent.

Photo-inactivation and efflux pump inhibition of methicillin resistant Staphylococcus aureus using thiolated cobalt doped ZnO nanoparticles.

Multidrug resistance (MDR) in bacteria is a major concern these days. One of the reasons is the mutation in efflux pump that prevents the retention of antibiotics and drugs in the bacterial cell. The current work is a step to overcome MDR in bacteria via inhibition of efflux pump and further photoinhibition by thiolated chitosan coated cobalt doped zinc oxide nanoparticles (Co-ZnO) in visible light. Co-ZnO were synthesized in a size range of 40-60 nm. Antibacterial activity of the Co-ZnO against methicillin resistant Staphylococcus aureus (MRSA) was found 100% at a concentration of 10 µg/ml upon activation in sunlight for 15 min. Interestingly, it was found that cobalt as a dopant was able to increase the photodynamic and photothermal activity of Co-ZnO, as in dark conditions, there was only 3-5% of inhibition at 10 µg/ml of nanoparticle concentration. Upon excitation in light, these nanoparticles were able to generate reactive oxygen species (ROS) with a quantum yield of 0.23 ±â€¯0.034. The nanoparticles were also generating heat, Because of the magnetic nature, thus helping in more killing. Thiolated chitosan further helped in blocking the efflux pump of MRSA. The current nanoparticles were also found biocompatible on human red blood cells (LD50 = 214 µg/ml). These data suggest that the MRSA killing ability was facilitated through efflux inhibition and oxidative stress upon excitation in visible light hence, were in accordance with previous findings.