Hydrothermally synthesized Ag-TiO2 nanofibers (NFs) for photocatalytic dye degradation and antibacterial activity.

This work successfully utilised eco-friendly green synthesis to produce Ag-TiO2 nanofibers (NFs). As pollution and energy limitations have become global issues, there is an ongoing need to develop more effective catalysts through straightforward and environmentally friendly methods. The Ag-TiO2 nanofibers (NFs) XRD pattern exhibits an anatase TiO2 and FCC crystal structure of Ag nanoparticles. The SEM investigation revealed a nanofiber-like surface morphology. The Ag-TiO2 nanofibers (NFs) exhibits an optical band gap energy is 2.5 eV. Methylene blue (MB), malachite green (MG), Congo red (CR), and crystal violet (CV) dye aqueous solutions were used to evaluate the photocatalytic performance of the synthesized Ag-modified TiO2 nanofibers (NFs) under direct sunlight irradiation. The effects of catalyst size on the efficient breakdown of MB dye were also investigated. The optimum catalyst concentration was found to be at 0.02 mg/mL. At 120 min of direct sunlight, the highest photosynthetic degradation efficiency (DE percentage) of 94% was achieved for MB dye. Ag-TiO2 nanofibers (NFs) have been demonstrated to have exceptional antibacterial activity against Gram-positive bacteria such as Staphylococcus aureus and Gram-negative bacteria E-Coli. Because of these great qualities, it seems likely that the Ag-TiO2 nanofibers (NFs) made could be a great photocatalyst for getting dye pollutants out of wastewater.

Investigate the suitability of g-C3N4 nanosheets ornamented with BiOI nanoflowers for photocatalytic dye degradation and PEC water splitting.

The two-step thermal polymerization and solvothermal approach is used to construct nano heterostructures of FCN and BiOI (bismuth oxeye iodide), both of which are Nobel metal-free materials. This work reports the effect nano-heterostructure on the micro-structural, light absorption capability, PEC properties and pollutant degradation efficiency of the synthesised heterostructures. The addition to that formation of FCN/BiOI nano-heterostructure enhances the solar light absorption. The FCN/BiOI nano heterostructure shows 10 times higher photocurrent density than the BCN nanostructure and 3.8 time higher that FCN. The FCN/BiOI has a high induced photo-current density (20.17 mA/cm2) and H2 evolution rate (3762 µmol h-1 cm-2) under solar light illumination (λ ≥ 420 nm) in comparison with the other. Furthermore, the photocatalytic performance of this material for the breakdown of methyl red dyes was much greater. Under solar light irradiation, the azo dyes were degraded in 90 min. The FCN/BiOI nano-heterostructure has a higher dye degradation efficiency of 97.91%. The rapid transport of photo-induced electrons in the FCN/BiOI nanocomposite is responsible for the improvement in PEC and PC performances. These impressive findings suggest that this nanocomposite might be used to facilitate the PEC water splitting and the PC degradation of MR in the presence of light. The current research provides insight on how to best tailor composition and structure for efficient FCN photo-electrocatalysis water splitting and Methyl red dye degradation.

Therapeutic effects of gold nanoparticles synthesized using Musa paradisiaca peel extract against multiple antibiotic resistant Enterococcus faecalis biofilms and human lung cancer cells (A549).

Botanical-mediated synthesis of nanomaterials is currently emerging as a cheap and eco-friendly nanotechnology, since it does not involve the use of toxic chemicals. In the present study, we focused on the synthesis of gold nanoparticles using the aqueous peel extract of Musa paradisiaca (MPPE-AuNPs) following a facile and cheap fabrication process. The green synthesized MPPE-AuNPs were bio-physically characterized by UV-Vis spectroscopy, FTIR, XRD, TEM, Zeta potential analysis and EDX. MPPE-AuNPs were crystalline in nature, spherical to triangular in shape, with particle size ranging within 50 nm. The biofilm inhibition activity of MPPE-AuNPs was higher against multiple antibiotic resistant (MARS) Gram-positive Enterococcus faecalis. Light and confocal laser scanning microscopic observations evidenced that the MPPE-AuNPs effectively inhibited the biofilm of E. faecalis when tested at 100 µg mL-1. Cytotoxicity studies demonstrated that MPPE-AuNPs were effective in inhibiting the viability of human A549 lung cancer cells at higher concentrations of 100 µg mL-1. The morphological changes in the MPPE-AuNPs treated A549 lung cancer cells were visualized under phase-contrast microscopy. Furthermore, the ecotoxicity of MPPE-AuNPs on the freshwater micro crustacean Ceriodaphnia cornuta were evaluated. Notably, no mortality was recorded in MPPE-AuNPs treated C. cornuta at 250 µg mL-1. This study concludes that MPPE-AuNPs are non-toxic, eco-friendly and act as a multipurpose potential biomaterial for biomedical applications.

Extracellular biosynthesis of silver nanoparticles using Bacillus sp. GP-23 and evaluation of their antifungal activity towards Fusarium oxysporum.

In last few decades nanoparticles have attracted and emerged as a field in biomedical research due to their incredible applications. The current research was focused on extracellular synthesis of silver nanoparticles (AgNPs) using cell free culture supernatant of strain GP-23. It was found that the strain GP-23 belonged to Bacillus species by 16S rRNA sequence analysis. Biosynthesis of AgNPs was achieved by addition of culture supernatant with aqueous silver nitrate solution, after 24 h it turned to brown color solution with a peak at 420 nm corresponding to the Plasmon absorbance of AgNPs by UV-Vis Spectroscopy. The nanoparticles were characterized by FTIR, XRD, HRTEM, EDX and AFM. The synthesized nanoparticles were found to be spherical in shape with size in the range of 7-21 nm. It was stable in aqueous solution for five months period of storage at room temperature under dark condition. The biosynthesized AgNPs exhibited strong antifungal activity against plant pathogenic fungus, Fusarium oxysporum at the concentration of 8 µg ml(-1). The results suggest that the synthesized AgNPs act as an effective antifungal agent/fungicide.

Sesbania grandiflora leaf extract mediated green synthesis of antibacterial silver nanoparticles against selected human pathogens.

Simple, effective and rapid approach for the green synthesis of silver nanoparticles (AgNPs) using leaf extract of Sesbania grandiflora and their in vitro antibacterial activity against selected human pathogens has been demonstrated in the study. Various instrumental techniques were adopted to characterize the synthesized AgNPs viz. UV-Vis, FTIR, XRD, TEM, EDX and AFM. Surface Plasmon spectra for AgNPs are centered at 422 nm with dark brown color. The synthesized AgNPs were found to be spherical in shape with size in the range of 10-25 nm. The presence of water soluble proteins in the leaf extract was identified by FTIR which were found to be responsible for the reduction of silver ions (Ag(+)) to AgNPs. Moreover, the synthesized AgNPs showed potent antibacterial activity against multi-drug resistant (MDR) bacteria such as Salmonella enterica and Staphylococcus aureus.

Synthesis of anisotropic silver nanoparticles using novel strain, Bacillus flexus and its biomedical application.

Synthesis of metallic nanoparticles has attracted by bacterial based production and alternative to physical and chemical approaches. The present work was focused to nominate a bacterial strain for synthesis of potential silver nanoparticles. The target was achieved by screening of 127 isolates from silver mining wastes. A strain designated S-27 found to be a potential candidate for rapid synthesis of silver nanoparticles among tested microorganisms. It was subjected to molecular characterization by 16S rDNA sequence analysis. It was found that S-27 belonging to Bacillus flexus. Synthesis of silver nanoparticles was achieved by addition of culture supernatants with aqueous silver nitrate solution, immediately it turns to brown colour solution showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles by UV-vis spectroscopy. Various instrumentation techniques, such as AFM, FESEM, XRD and FTIR, were adopted to characterize the synthesized nanoparticles. Anisotropic nanoparticles, such as spherical and triangular shaped nanoparticles, have been synthesized and sizes were found to be 12 and 65 nm, respectively. It was stable in aqueous solution in five months period of storage at room temperature in the dark. Synthesized nanoparticles showed efficacy on antibacterial property against clinically isolated multi-drug resistant (MDR) microorganisms. It is suggested that biogenic synthesis of nanoparticles have wide-application in medicine and physical chemistry and it can produce with eco-friendly, easy downstream processing and rapid scale-up processing.

Biosynthesis of silver nanoparticles from Tribulus terrestris and its antimicrobial activity: a novel biological approach.

In the recent decades, increased development of green synthesis of nanoparticles is inevitable because of its incredible applications in all fields of science. There were numerous work have been produced based on the plant and its extract mediated synthesis of nanoparticles, in this present study to explore that the novel approaches for the biosynthesis of silver nanoparticles using plant fruit bodies. The plant, Tribulus terrestris L. fruit bodies are used in this study, where the dried fruit body extract was mixed with silver nitrate in order to synthesis of silver nanoparticles. The active phytochemicals present in the plant were responsible for the quick reduction of silver ion (Ag(+)) to metallic silver nanoparticles (Ag(0)). The reduced silver nanoparticles were characterized by Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), XRD, FTIR, UV-vis spectroscopy. The spherical shaped silver nanoparticles were observed and it was found to be 16-28 nm range of sizes. The diffraction pattern also confirmed that the higher percentage of silver with fine particles size. The antibacterial property of synthesized nanoparticles was observed by Kirby-Bauer method with clinically isolated multi-drug resistant bacteria such as Streptococcus pyogens, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The plant materials mediated synthesis of silver nanoparticles have comparatively rapid and less expensive and wide application to antibacterial therapy in modern medicine.