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Current researches on detrimental chemical hazards have successfully put forward the noxious effects of toxic metal ion and released harmful organic dyes (such as TB and Rh-B) upon discharge into the environment. However, the exposure of Hg2+ ions is the most alarming among all. In order to get rid of its deleterious effects, the detection of Hg2+ ion is urgent. Motivated by this, we have for the first time presented an accurate picomolar level detecting colorimetric sensor stabilized by Hibiscus mutabilis leaf extract. It manifested outstanding selectivity, superb single shot response, and high sensitivity towards Hg2+ ion with a reliable detection limit of 48 pM. Moreover, our synthesized nanoparticles were found eligible as a capable photon induced catalyst for the degradation of commercially discharged toxic anthropogenic organic dyes TB and Rh-B, which were degraded up to 94% and 97%, respectively. The used experimental approaches to support our investigation were UV-Vis, DLS, HRTEM, XRD, FESEM, XPS, and zeta potential analysis. It was ensured that Ag(Hg) amalgam formation was the mechanism for the detection of Hg2+ ion. Intriguingly, the sensitivity of the system was progressively promoted to a lower detection limit (30 pM) in the presence of high salt concentration. We anticipate that this research could pose revolutionary impact and can encourage the scientists to follow the "go green" strategy for the development of risk free supplementary nanoparticles to fight against environmental hazards. [ABSTRACT FROM AUTHOR]

This study describes the eco‐friendly, low‐cost and room‐temperature synthesis of gold nanoparticles from Musa balbisiana leaf extract, which acts as both reducing and stabilizing agent, and characterized by ultraviolet−visible (UV–vis) light spectroscopy, fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE‐SEM), analytical transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDAX) and dynamic light scattering (DLS) instruments. These nanoparticles showed an average diameter of 33.83 ± 3.39 nm, which was confirmed from the size distribution histogram. The bactericidal activity of these nanoparticles was confirmed using bacteria Escherichia coli and Staphylococcus aureus at 1 and 2 nM minimum inhibitory concentrations, respectively. The interaction between nanoparticles and human serum albumin (HSA) was investigated, as this plays significant roles in biological systems. The nature of interaction, binding parameters and structural variation of HSA in the presence of these nanoparticles have been evaluated using several useful spectroscopic approaches such as UV–vis, FTIR, time‐resolved and steady‐state fluorescence, and circular dichroism in addition to the measurement of zeta potential. This interaction study revealed that static quenching occurs in this process with minimal alteration in the secondary structure, but the native structure of HSA remained unaltered. The binding constant and thermodynamic parameters of this interaction process were also evaluated. [ABSTRACT FROM AUTHOR]

In recent years, green synthesized nanoparticles from plant extract have drawn a great interest due to their prospective nanomedicinal application. This study investigates a proficient, safer, and sustainable way for the preparation of AgNPs using medicinal plant Pongamia pinnata (family: Leguminoseae, species: Pinnata) seeds extract without using any external reducing and stabilizing agent. Both ultraviolet-visible spectrum at λmax = 439 nm and energy dispersive X-ray spectra proof the formation of AgNPs. An average diameter of the AgNPs was 16.4 nm as revealed from transmission electron microscope. Hydrodynamic size (d = ~19.6 nm) was determined by dynamic light scattering (DLS). Zeta potential of AgNPs was found to be -23.7 mV, which supports its dispersion and stability. Fourier transform infrared study revealed that the O -- H, C = O, and C-O-C groups were responsible for the formation of AgNPs. The antibacterial activity of the synthesized AgNPs was checked against Escherichia coli ATCC 25922. AgNPs at its LD50 dose exhibited synergistic effect with ampicillin. Because protein-AgNPs association greatly affects its adsorption, distribution, and functionality and can also influence the functions of biomolecules. So in order to understand the adsorption and bioavailability, we investigated by fluorescence, ultraviolet-visible, and circular dichroism spectroscopic methods the interaction of synthesized AgNPs toward human serum albumin. The binding affinity and binding sites of human serum albumin toward AgNPs were measured by using the fluorescence quenching data. The circular dichroism spectroscopic results revealed that there was a negligible change of α-helical content in their native structure. Overall, these AgNPs show versatile biological activities and may be applied in the field of nanomedicine. [ABSTRACT FROM AUTHOR]

This study describes the eco-friendly, low-cost and room-temperature synthesis of gold nanoparticles from Musa balbisiana leaf extract, which acts as both reducing and stabilizing agent, and characterized by ultraviolet-visible (UV-vis) light spectroscopy, fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), analytical transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDAX) and dynamic light scattering (DLS) instruments. These nanoparticles showed an average diameter of 33.83 ± 3.39 nm, which was confirmed from the size distribution histogram. The bactericidal activity of these nanoparticles was confirmed using bacteria Escherichia coli and Staphylococcus aureus at 1 and 2 nM minimum inhibitory concentrations, respectively. The interaction between nanoparticles and human serum albumin (HSA) was investigated, as this plays significant roles in biological systems. The nature of interaction, binding parameters and structural variation of HSA in the presence of these nanoparticles have been evaluated using several useful spectroscopic approaches such as UV-vis, FTIR, time-resolved and steady-state fluorescence, and circular dichroism in addition to the measurement of zeta potential. This interaction study revealed that static quenching occurs in this process with minimal alteration in the secondary structure, but the native structure of HSA remained unaltered. The binding constant and thermodynamic parameters of this interaction process were also evaluated., (© 2019 John Wiley & Sons, Ltd.)