Green synthesis and characterization of silver nanoparticles using Pteris vittata extract and their therapeutic activities

Green synthesis and characterization of silver and copper nanoparticles and their use as an effective adsorbent for chromium removal and recovery from wastewater

Chromium (Cr) is one of the hazardous heavy metals that is naturally carcinogenic and causes various health problems. Metallic nanoparticles such as silver and copper nanoparticles (Ag NPs and Cu NPs) have gained great attention because of their unique chemical, physical, and biological attributes, serving diverse and significant role in various useful and sustainable applications. In the present study, both of these NPs were synthesized by green method in which Azadirachta indica plant extract was used. These nanoparticles were characterized by using advanced instrumental techniques such as Fourier transmission infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope attached with energy-dispersive spectroscopy (SEM-EDS), and elemental mapping. These environmentally friendly nanoparticles were utilized for the batch removal of Cr from the wastewater. For analysis of adsorption behaviour, a range of kinetic isotherm models (Freundlich, Temkin, Dubinin, and Langmuir) and kinetic models (pseudo-first-order and pseudo-second-order) were used for the Cu-NPs and Ag-NPs. Cu NPs exhibited the highest Cr removal efficiency (96%) within a contact time of 10-15 min, closely followed by Ag NPs which achieved a removal efficiency of 94% under the similar conditions. These optimal outcomes were observed at a sorbent dose of 0.5 g/L for Ag NPs and 0.7 g/L for Cu NPs. After effectively capturing Cr using these nanoparticles, the sorbates were examined through SEM-EDX analysis to observe how much Cr metal was attached to the nanoparticles, potentially for future use. The analysis found that Ag-NPs captured 18% of Cr, while Cu-NPs captured 12% from the aqueous solution. More precise experimental conditions are needed for higher Cr removal from wastewater and determination of the best conditions for industrial-level Cr reuse. Although nanomaterial exhibit high efficiency and selectivity for Cr removal and recovery from wastewater, more research is necessary to optimize their synthesis and performance for industrial-scale applications and develop efficient methods for Cr removal and recovery.

Antimicrobial effect of pimozide by targeting ROS-mediated killing in Staphylococcus aureus

In spite of the higher nosocomial and community-acquired infections caused by Staphylococcus aureus, emerging drug resistance is a leading cause of increased mortality and morbidity associated with the overuse of antimicrobials. It is an emergent need to find out new molecules to combat such infections. In the present study, we analyzed the antibacterial effect of pimozide (PMZ) against gram-positive and gram-negative bacterial strains, including methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) S. aureus. The growth of MSSA and MRSA was completely inhibited at concentrations of 12.5 and 100 μg/mL, respectively, which is referred to as 1× minimum inhibitory concentration (MIC). The cell viability was completely eliminated within 90 min of PMZ treatment (2× MIC) through reactive oxygen species (ROS)-mediated killing without affecting cell membrane permeability. It suppressed α-hemolysin production and biofilm formation of different S. aureus strains by almost 50% at 1× MIC concentration, and was found to detach matured biofilm. PMZ treatment effectively eliminates S. aureus infection in Caenorhabditis elegans and improves its survival by 90% and is found safe to use with no hemolytic effect on human and chicken blood tissues. Taken together, it is concluded that PMZ may turn out to be an effective antibacterial for treating bacterial infections including MSSA and MRSA.

Biogenic silver based nanostructures: Synthesis, mechanistic approach and biological applications

The alarming impact of antibiotic resistance sparked the quest for complementary treatments to overcome the confrontation over resistant pathogens. Metallic nanoparticles, especially silver nanoparticles (Ag NPs) have gained a much attention because of their remarkable biological characteristics. Moreover, their medicinal properties can be enhanced by preparing the composites with other materials. This article delves a comprehensive review of biosynthesis route for Ag NPs and their nanocomposites (NCs) with in-depth mechanism, methods and favorable experimental parameters. Comprehensive biological features Ag NPs such as antibacterial, antiviral, antifungal have been examined, with a focus on their potential uses in biomedicine and diagnostics has also been discussed. Additionally, we have also explored the hitches and potential outcomes of biosynthesis of Ag NPs in biomedical filed.

Innovative green/non-toxic Bi2S3@g-C3N4 nanosheets for dark antimicrobial activity and photocatalytic depollution: Turnover assessment

Herein, green and non-toxic bismuth sulphide@graphitic carbon nitride (Bi₂S₃@g-C₃N₄) nanosheets (NCs) were firstly synthesized by ultrasonicated-assisted method and characterized with different tool. Bi₂S₃@g-C₃N₄ NCs antimicrobial activity tested against three types of microbes. As well the heterostructured Bi₂S₃@g-C₃N₄ NCs was investigated for removing dye and hexavalent chromium under visible light and showed high efficiency of photocatalytic oxidation/reduction higher than g-C₃N₄ alone, attributing to lower recombination photogenerated electron-hole pairs. Bi₂S₃@g-C₃N₄ NCs showed high antimicrobial efficiencies against Staphylococcus aureus (S. aureus) as a Gram positive bacterium, Escherichia coli (E. Coli)as a Gram negative bacterium and Candida albicans (C. albicans) and that the disinfection rates are 99.97%, 99.98% and 99.92%, respectively. The core mechanism is that the bacterial membrane could be destroyed by reactive oxygen species. The Bi₂S₃@g-C₃N₄ NCs is promising for environmental disinfection including water and public facilities disinfection and solar photocatalytic depollution. Turnover number (TON) and Turnover frequency (TOF) are used as concise assessment indicator for photocatalytic efficiency.

Green Synthesis and Characterisation of Silver Nanoparticles Using Cassia tora Seed Extract and Investigation of Antibacterial Potential

Nanoparticle research is fascinating and getting hold of consequences due to the wide variety of applications in the biomedical field. Green synthesis of nanoparticles is a cost-effective and eco-friendly approach. It can be synthesised using fungi, algae, plant, yeast, bacteria, microbial enzymes etc. Our current research study focuses on the green synthesis of silver nanoparticles using seed extract of Cassia tora. The colour change from yellow to red colour confirms the formation of silver nanoparticles. The synthesised silver nanoparticles were characterised by Ultraviolet-Visible spectroscopy, Fourier-transform infrared (FTIR), X-ray diffraction analysis (XRD), Scanning Electron Microscopy (SEM) and antibacterial efficacy against three different strains were analysed. The surface plasmon resonance of synthesised AgNPs using Cassia tora seed extract shows maximum absorption peak at 423 nm in UV-visible spectroscopy. X-ray diffraction displays the crystalline nature of synthesised AgNPs and they exhibited four distinct peaks at 36.69°, 42.92°, 63.27° and 76.46°. The particle size of synthesised AgNPs observed through SEM was found to be 55.80 nm, 58.97 nm, 61.06 nm, 63.26 nm and 64.80 nm. S.aureus exhibited maximum zone of inhibition of 12 mm and 13 mm when treated with 25 and 50 μl of the synthesised nanoparticles. Thus, the green synthesised silver nanoparticle using Cassia tora seed extract proved to possess strong anti-bacterial activity.