Gargi Dinda; Dipankar Halder; Atanu Mitra
Abstract
We report the successful synthesis of copper nanoparticle (CuNP)-starch composite employing low cost green protocol without inert gas protection. UV-Vis spectroscopy, X-Ray diffraction (XRD) and Transmission electron microscopy (TEM) were used to characterize the CuNP-starch composite. Mono-disperse ...
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We report the successful synthesis of copper nanoparticle (CuNP)-starch composite employing low cost green protocol without inert gas protection. UV-Vis spectroscopy, X-Ray diffraction (XRD) and Transmission electron microscopy (TEM) were used to characterize the CuNP-starch composite. Mono-disperse almost spherical CuNP having average diameter 4.02 ± 0.076 nm was obtained. The catalytic activity of the as-synthesized CuNP-starch composite during reduction of pollutants, like, 4-nitrophenol (4-NP) and dyes, Eosine Blue (EB), Eriochrome Black T (EBT) and Brilliant Cresyl Blue (BCB by NaBH4 has been investigated. High catalytic efficiency of the composite was demonstrated by rapid decrease of the intensity of the UV-Vis absorption peaks at respective λmax of the pollutants with time when reaction mixture contained NaBH4 and small quantity of CuNP-starch composite. The rate constant of each processes was calculated by considering that the reactions follow pseudo-first-order kinetics with respect to substrate. The obtained rate constants for 4-NP, EB, EBT and BCB are 0.021S-1, 0.011S-1, 0.036S-1 and 0.032S-1 respectively. The other application, antibacterial activity was tested against Gm positive and Gm negative bacteria. Plate count and minimum inhibitory concentration (MIC) studies show higher susceptibility of Gm positive bacteria towards CuNP-starch composite. The as-synthesized CuNP-starch composite may find potential application in the field of environmental remedies and antibacterial formulations. Copyright©2018 VBRI Press.
M.K. Debanath; R.K. Saha; S.M. Borah; E. Saikia; K.K. Saikia
Abstract
In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized ...
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In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive analysis of X-rays (EDAX), high resolution transmission electron microscopy (HRTEM), UV-vis absorption spectroscopy and photoluminescence (PL) spectroscopy for their structural and optical properties. Antibacterial properties have been studied by Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria. XRD study showed hexagonal wurtzite crystal structure of the prepared ZnO:Cu and nanoformation of the as-synthesized NPs. Nanoparticle formation have been finally confirmed by HRTEM analysis. Antibacterial studies showed excellent resistance of ZnO:Cu to S. aureus and E. coli respectively. Copyright © 2018 VBRI Press.
Rachna .; Baljeet S. Saharan .; Mahender S. Yadav .; Nisha Sharma .
Abstract
A simple and efficient synthesis of silver nanoparticles (AgNPs) is reported here using red Dianthus caryophyllus flower, acting both as reducing and capping agent. The resultant silver colloids were characterized using UV-visible spectrophotometer, X-ray Diffractometer (XRD) and Transmission electron ...
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A simple and efficient synthesis of silver nanoparticles (AgNPs) is reported here using red Dianthus caryophyllus flower, acting both as reducing and capping agent. The resultant silver colloids were characterized using UV-visible spectrophotometer, X-ray Diffractometer (XRD) and Transmission electron microscope (TEM). The surface absorption plasmon response and kinematics of reduction of silver ions were observed by UV-visible spectroscopy. The crystalline fcc structure of AgNPs was confirmed by its XRD pattern. Their morphological study was done with TEM, showing spherically shaped AgNPs in the range 10-20 nm. The antibacterial action was also studied using Agar well diffusion method against pathogenic bacteria cultures (Staphylococcus aureus, Bacillus cereus and Escherichia coli). AgNPs showed better antimicrobial activity against S. aureus culture. Copyright © 2018 VBRI Press.
Rajat K. Saha; Mrinal K. Debanath; Eeshankur Saikia; Vedant V. Borah; Kandarpa K. Saikia
Abstract
ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the ...
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ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the XRD data obtained, by using the tools of Nonlinear Dynamical Theory (NLD). One of the tools used called Lyapunov Exponent, bears the signature of the dynamical evolution of the particles as well as structure formation. This is calculated in order to quantify the underlying strange attractor present in the nanosystems, which happens to be the driving force behind the structure formation. The changes in the values of this parameter with the variation of the physical and chemical conditions, would pave the way for an efficient calibration for meaningful biological applications, which happens to be the focus of the present work. Differently sized ZnO nano particles are obtained by changing dopant percentage for inhibiting human pathogenic bacteria. Calibrations are made between the Zone of Inhibition (ZOI) and Lyapunov Exponent to obtain the required dopant percentage for a given ZOI vis-à-vis the same anti-bacterial effectiveness in terms of ZOI of a ZnO doped nano particle. Copyright © 2016 VBRI Press.
Aftab H. Mondal; Mohammad T. Siddiqui; Kehkashan Siddiqui; Qazi M. Rizwanul Haque
Abstract
In the present work, biosynthesis of silver nanoparticles (AgNPs) using isolate of Shigella sp. AS8 culture supernatant as a reducing agent has been demonstrated. Synthesis of AgNPs was completed within 180 min of incubation at 35 °C under bright light condition. The biosynthesized nanoparticles ...
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In the present work, biosynthesis of silver nanoparticles (AgNPs) using isolate of Shigella sp. AS8 culture supernatant as a reducing agent has been demonstrated. Synthesis of AgNPs was completed within 180 min of incubation at 35 °C under bright light condition. The biosynthesized nanoparticles were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Dynamic light scattering (DLS), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray (EDX) and Atomic force microscopy (AFM). The formation of brown color reaction product with strong UV-vis spectrum absorption maxima at 411 nm due to surface plasmon resonance (SPR) indicated the synthesis of AgNPs. FTIR spectrum confirmed association of supernatant protein molecules with synthesized nanoparticles. DLS, TEM, FE-SEM and AFM showed biosynthesized nanoparticles were spherical in shape with an average size of 20 nm. EDX data analysis reveals presence of metallic silver. While, XRD analysis revealed that synthesized particles were pure and crystalline in nature. Further, AgNPs were evaluated as an antibacterial agent against extended spectrum β-lactamase (ESBL) positive water-borne pathogens. The results of present study suggest that biosynthesized AgNPs can be used to combat ESBL producing multidrug resistant bacteria.