Recent advances in the synthesis, characterization and biomedical applications of zinc oxide nanoparticles.

Zinc oxide nanoparticles (ZnONPs) have become the widely used metal oxide nanoparticles and drawn the interest of global researchers due to their biocompatibility, low toxicity, sustainability and cost-effective properties. Due to their unique optical and chemical properties, it emerges as a potential candidate in the fields of optical, electrical, food packaging and biomedical applications. Biological methods using green or natural routes are more environmentally friendly, simple and less use of hazardous techniques than chemical and/or physical methods in the long run. In addition, ZnONPs are less harmful and biodegradable while having the ability to greatly boost pharmacophore bioactivity. They play an important role in cell apoptosis because they enhance the generation of reactive oxygen species (ROS) and release zinc ions (Zn2+), causing cell death. Furthermore, these ZnONPs work well in conjunction with components that aid in wound healing and biosensing to track minute amounts of biomarkers connected to a variety of illnesses. Overall, the present review discusses the synthesis and most recent developments of ZnONPs from green sources including leaves, stems, bark, roots, fruits, flowers, bacteria, fungi, algae and protein, as well as put lights on their biomedical applications such as antimicrobial, antioxidant, antidiabetic, anticancer, anti-inflammatory, antiviral, wound healing, and drug delivery, and modes of action associated. Finally, the future perspectives of biosynthesized ZnONPs in research and biomedical applications are discussed.

Regulation of Autophagy Machinery in Magnaporthe oryzae.

Plant diseases cause substantial loss to crops all over the world, reducing the quality and quantity of agricultural goods significantly. One of the world's most damaging plant diseases, rice blast poses a substantial threat to global food security. Magnaporthe oryzae causes rice blast disease, which challenges world food security by causing substantial damage in rice production annually. Autophagy is an evolutionarily conserved breakdown and recycling system in eukaryotes that regulate homeostasis, stress adaption, and programmed cell death. Recently, new studies found that the autophagy process plays a vital role in the pathogenicity of M. oryzae and the regulation mechanisms are gradually clarified. Here we present a brief summary of the recent advances, concentrating on the new findings of autophagy regulation mechanisms and summarize some autophagy-related techniques in rice blast fungus. This review will help readers to better understand the relationship between autophagy and the virulence of plant pathogenic fungi.

Biofabrication and characterization of cyanobacteria derived ZnO NPs for their bioactivity comparison with commercial chemically synthesized nanoparticles.

Due to unique properties of the nanoparticles (NPs) with biocompatibility, their application as drug in drug delievery and diagnostics, the recent scientific branch nanotechnology has emerged as hope in modern medicine. Zinc oxide nanoparticles (ZnO NPs) have gained tremendous interest due to their potential use as chemotherapeutic and antimicrobial agents. They are included in the category of "generally recognized as safe (GRAS) metal oxide". There is an urgent need for developing additional sources of ZnO NPs. Therefore, in the present study 30 cyanobacterial extracts were screened for ZnO NPs synthesis.. The color change of the reaction mixture from blue to pale white indicated the synthesis of ZnO NPs. It was further confirmed by UV-Visible spectroscopy that showed the absorption peak at 372 nm. The SEM analysis during screening revealed that Oscillatoria sp. synthesized smallest ZnO NPs (~40 nm) that were further optimized for their higher yield by altering reaction conditions (pH, temperature, reaction time, concentration of extract and metal precursor). Best conditions for ZnO NPs synthesis are (0.02 M zinc nitrate, 10 ml of extract volume, pH 8, at 80 °C for 3 h). The NPs were purified through calcination at 350°C and characterized by UV-Vis, FTIR, XRD, SEM-EDAX, TEM, Zeta potential and DLS analysis. The comparative analysis of purified biogenic ZnO NPs with commercial chemically synthesized ZnO NPs (CS), exhibited their superior nature as antioxidant and anti-bacterial agent against both gram-positive and gram-negative bacteria. Synergistic effects of biogenic ZnO NPs and streptomycin additionally favored for their future use as a potential biomedical agent.

Toxicological assessment of Phormidium sp. derived copper oxide nanoparticles for its biomedical and environmental applications.

Driven by the need to biosynthesized alternate biomedical agents to prevent and treat infection, copper oxide nanoparticles (CuONPs) have surfaced as a promising avenue. Cyanobacteria-derived synthesis of CuONPs is of substantive interest as it offers an eco-friendly, cost-effective, and biocompatible route. In the present study biosynthesized CuONPs were characterized and investigated regarding their toxicity. Morphological analysis using TEM, SEM and AFM showed the spherical particle size of 20.7 nm with 96% copper that confirmed the purity of CuONPs. Biogenic CuONPs with IC50 value of 64.6 µg ml-1 showed 90% scavenging of free radicals in superoxide radical scavenging assay. CuONPs showed enhanced anti-inflammatory activity by 86% of protein denaturation with IC50 value of 89.9 µg ml-1. Biogenic CuONPs exhibited significant toxicity against bacterial strains with lowest MIC value of 62.5 µg ml-1 for B. cereus and fungal strain with a MIC value of 125 µg ml-1 for C. albicans. In addition CuONPs demonstrated a high degree of synergistic interaction when combined with standard drugs. CuONPs exhibited significant cytotoxicity against non-small cell lung cancer with an IC50 value of 100.8 µg ml-1 for A549 and 88.3 µg ml-1 for the H1299 cell line with apoptotic activities. Furthermore, biogenic CuONPs was evaluated for their photocatalytic degradation potential against methylene blue dye and were able to removed 94% dye in 90 min. Free radical scavenging analysis suggested that CuONPs assisted dye degradation was mainly induced by hydroxide radicals. Biogenic CuONPs appears as an eco-friendly and cost effective photocatalyst for the treatment of wastewater contaminated with synthetic dyes that poses threat to aquatic biota and human health. The present study highlighted the blend of biomedical and photocatalytic potential of Phormidium derived CuONPs as an attractive approach for future applications in nanomedicine and bioremediation.

Investigation of morphological and biochemical changes of zinc oxide nanoparticles induced toxicity against multi drug resistance bacteria.

BACKGROUND: Biofilms are microbial colonies that remain enclosed in an organic polymeric matrix substance on biotic and abiotic surfaces, allowing them to colonize medical equipments and involved in most device associated life intimidating infections. Due to their antimicrobial resistance there is an urgent need to discover novel biofilm preventive and therapeutic agents. METHODS: ZnO NPs were synthesized using cyanobacteria Gleocapsa gelatinosa cell extract through green and cost-effective approach. Physiochemical characterization was done to determine their morphologies and size distribution. Antibiofilm and eradication activity of ZnO NPs was determined. Cell viability and internalization ability of ZnO NPs into biofilm was analyzed by flow cytometry. Confocal microscopy was done to visualize the disrupted biofilm morphology treated with ZnO NPs. RESULTS: It was observed that ZnONPs were spherical in shape with 31-35 nm size and were moderately dispersed. ZnO NPs exhibited high antibiofilm activity against B. cereus and E. coli with minimum biofilm inhibitory concentration (MBIC) of ZnO NPs at 46.8 µg ml-1 and 93.7 µg ml-1. Flow cytometry analysis confirmed the reduced bacterial cell viability due to increased permeability, altered bacterial growth and enhanced production of intracellular ROS. Disruption of membrane integrity exhibited with reduced exopolysaccharides secretion and leakage of nucleic acids through UV-Vis spectroscopy. Results of confocal microscopy highlighted strong interaction of ZnO NPs with intracellular components leading to biofim destruction. CONCLUSIONS: This study emphasizes the potential mechanisms underlying the selective bactericidal properties of ZnO NPs and highlighted the strong interaction of ZnO NPs with intracellular components leading to biofim destruction. Therefore, ZnO NPs could be considered as a promising antibiofilm agent and thus could expand the possibility to use as therapeutic agent.

Screening, characterisation and bioactivities of green fabricated TiO2 NP via cyanobacterial extract.

The present study was aimed at exploring 37 strains of cyanobacteria for the biofabrication of TiO2 NP and evaluation of their antioxidant, antifungal, antibacterial and hemolytic activity. Screening of cyanobacterial strains was done via SEM, followed by optimisation and characterisation of the best strain. Synechocystis NCCU-370 appeared as the best strain for the synthesis of TiO2 NP in terms of size (73.39 nm) and time (24 h) after screening. Following optimisation, nanoparticles were synthesised in 12 h having an average grain size of 16 nm. The aqueous extract preparation required heating of 5 mg/ml of powdered biomass to 60 °C for 10 min. Optimum conditions for the synthesis of TiO2 NP were found to be pH 7, 30 °C and 12-h cell extract exposure to 0.1 mM of salt. Antioxidant activity was evaluated via DPPH, ABTS and FRAP assay. Antifungal potential was explored against Candida albicans (MIC = 125 µg/ml), Candida glabrata (MIC = 500 µg/ml) and Candida tropicalis (MIC = 250 µg/ml), whereas antibacterial potential was gauged for Bacillus cereus (MIC = 31.25 µg/ml), Escherichia coli (MIC = 31.25 µg/ml) and Klebsiella pneumoniae (MIC = 500 µg/ml) strains. Biogenic TiO2 NP demonstrated partial synergistic effect and excellent biocompatibility.

Toxicity of NSAID drug (paracetamol) to nontarget organism-Nostoc muscorum.

Due to many folds increase in application of human and veterinary medicines, pharmaceuticals, a new category of pollutants, have emerged in our environment. They exist as residues in rivers, sewage effluents, streams, surface, ground, and potable water. Paracetamol (acetaminophen) is one such drug that is used as an antipyretic and analgesic medicine. It is a non-steroidal antiinflammatory drug (NSAID) and is easily available in the market because no medical prescription is necessary for its purchase and use. Paracetamol remains physiologically active even after their expiry period. Their detection in the environment in bioactive form has resulted in adverse effects on nontarget species. To determine the effect of paracetamol on aquatic photosynthetic organic (Cyanobacteria-Nostoc muscorum), present study was performed. Paracetamol (25 mg/L, 50 mg/L, 75 mg/L, 100, 125, and 150 mg/L) exposure showed toxic responses on the test organism by generating oxidative stress (MDA, H2O2, O2.-). Paracetamol caused a significant decrease in growth of cyanobacteria and showed EC50 113.68 mg/L after the 6th day of treatment. Photosynthetic pigments (chlorophyll, carotenoid, and phycobiliprotein) decreased with paracetamol increase. Antioxidant enzymatic (SOD, CAT, APX, GST, and GR) and osmolyte (Proline) also increased with increase in paracetamol to counteract the oxidative stress.