Green Synthesis of Copper Oxide Nanoparticles from the Leaves of <i>Aegle marmelos</i> and Their Antimicrobial Activity and Photocatalytic Activities

The leaves of the Aegle marmelos plant were used for the green synthesis of copper oxide nanoparticles and further characterized by different techniques, including (Ultra Violet-Visible) UV-Vis, Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), Transmission electron microscopy (TEM) and X-ray diffraction (XRD). The UV-Vis showed a peak at 330 nm, which may be due to the Surface Plasmon Resonance phenomenon. XRD analysis showed the crystalline nature of copper oxide nanoparticles (CuO NPs). In contrast, SEM showed that nanoparticles were not aggregated or clumped, EDX showed the presence of elemental copper., and further, the TEM analysis revealed the average particle size of copper oxide nanoparticles to be 32 nm. The Minimum Inhibitory Concentration (MIC) for Escherichia coli (E. coli) and Staphylococcusaureus (S. aureus) was found to be 400 µg/mL, whereas for Candida albicans (C. albicans) and Candida dubliniensis (C. dubliniensis) it was 800 µg/mL. The zone of inhibition in the well diffusion assay showed the antimicrobial activity of copper oxide nanoparticles, and it also showed that as the concentration of copper oxide nanoparticles increased, the zone of inhibition also increased. Further, the electron microscopic view of the interaction between copper oxide nanoparticles and C. albicans cells showed that CuO NPs were internalized and attached to the cell membrane, which caused changes in the cellular structure and caused deformities which eventually led to cell death. The prepared CuO NPs showed significant photocatalytic degradation of organic dyes in the presence of sunlight

Dimercaptosuccinic Acid Functionalized Polystyrene Column for Trace Concentration Determination of Heavy Metal Ions: Experimental and Theoretical Calculation Studies

Metal ion studies in wastewater are required on a regular basis for environmental monitoring and assessment. Less metal ion concentrations and the interference from complex sample matrices remains challenging for instrumental quantification. Herein, we proposed a fix-bed solid phase extraction method, consisting of a newly prepared dimercaptosuccinic acid functionalized polystyrene beads. The ligand forms stable complex with Hg(II), Pb(II), and Cd(II), evident by experimental as well as density functional theory. The metal-ligand stabilization energy calculations, suggested the higher selectivity of polystyrene dimercaptosuccinic acid (PSDMSA) toward Pb(II) compared to Cd(II) and Hg(II). The prepared adsorbent was utilized to enrich Hg(II), Pb(II), and Cd(II) ions from environmental samples. Column parameters were studied in detail and optimized accordingly. The preconcentration factor for Hg(II), Pb(II), and Cd(II) were found to be 900, with the preconcentration limit of 0.74 µg L−1. The detection limit for Pb(II), Cd(II), and Hg(II) ions was found to be 1.3 ± 0.2, 1.5 ± 0.3, and 1.8 ± 0.3 ng L−1, respectively. The method accuracy was tested against systematic and continuous errors by standard addition method (&lt;5% RSD). Real samples was successfully analyzed following the proposed method

Biosynthesis of Gold Nanoparticles and Its Effect against <i>Pseudomonas aeruginosa</i>

Antimicrobial resistance has posed a serious health concern worldwide, which is mainly due to the excessive use of antibiotics. In this study, gold nanoparticles synthesized from the plant Tinospora cordifolia were used against multidrug-resistant Pseudomonas aeruginosa. The active components involved in the reduction and stabilization of gold nanoparticles were revealed by gas chromatography–mass spectrophotometry(GC-MS) of the stem extract of Tinospora cordifolia. Gold nanoparticles (TG-AuNPs) were effective against P. aeruginosa at different concentrations (50,100, and 150 µg/mL). TG-AuNPs effectively reduced the pyocyanin level by 63.1% in PAO1 and by 68.7% in clinical isolates at 150 µg/mL; similarly, swarming and swimming motilities decreased by 53.1% and 53.8% for PAO1 and 66.6% and 52.8% in clinical isolates, respectively. Biofilm production was also reduced, and at a maximum concentration of 150 µg/mL of TG-AuNPs a 59.09% reduction inPAO1 and 64.7% reduction in clinical isolates were observed. Lower concentrations of TG-AuNPs (100 and 50 µg/mL) also reduced the pyocyanin, biofilm, swarming, and swimming. Phenotypically, the downregulation of exopolysaccharide secretion from P. aeruginosa due to TG-AuNPs was observed on Congo red agar plate