Showing 4 results for Silver Nanoparticles
Z. Abadi, S. M. Bidoki, V. Mottaghitalab, A. Benvidi, A. Shams-Nateri,
Volume 11, Issue 3 (9-2014)
Abstract
Silver nanoparticles are being given considerable attention because of their interesting properties and
potential applications. One such exploitable use is as the major constituent of conductive inks and pastes used for
printing various electronic components. This paper presents a novel direct-writing process for fabrication of the first
deposited silver nanoparticles (AgNPs) (50-200nm) electrode via a thermal inkjet printer. In this method, AgNPs were
chemically deposited by ejection of ascorbic acid and silver nitrate solutions onto different substrates such as paper
and textile fabrics. Silver deposited patterns were used as electrodes in different electrochemical experiments and their
morphology was also investigated in SEM observations. The highest conductivity of deposited electrodes obtained on
paper as the substrate was found to be around 5.54x105 S/m. Inkjet fabricated electrodes exhibited acceptable
electrochemical behavior in experiments designed for measuring the concentration of hydrogen peroxide as a
fundamental procedure for early determination of glucose. This novel inkjet silver deposition technique is introduced
to be considered as a promising method for ultimate single step fabrication of different electrochemical bio-sensors.
A. Thakur, G. Reddy,
Volume 17, Issue 3 (9-2020)
Abstract
Mercury, one of the common pollutants in water, is known to affect human health adversely upon exposure. It is released in water not only by various natural processes but also by human activities. Methods developed so far for the detection of mercuric ions in water have limitations like sensitivity range, complex setup, skillful operation etc. Silver nanoparticles, due to unique properties, have been explored by researchers to develop better detection systems. Stable silver nanoparticles can be easily synthesized by methods of green chemistry, its reaction with mercuric ion can be easily observed by changes in color and UV-Vis spectra. The absorbance data from UV-Vis spectra can also be used in quantifying mercury concentration. In this paper, stable silver nanoparticles synthesized using silver nitrate as precursor, sodium lignosulphonate (LS) as reducing and stabilizing agent under microwave radiation are explored for detection of mercuric ions in water. Formation of AgNP was confirmed by UV-Vis band at 403.5nm. The intensity of this band showed a proportional decrease with increasing Hg+2 concentration. Hg+2 ions were detected by a distinct color change at higher concentration of Hg+2 also. The limit of detection (LOD) calculated from the observed absorbance data to be 0.7 ppm.
Richa Singh,
Volume 21, Issue 1 (3-2024)
Abstract
Drug-resistance among bacteria is a concerning issue in medical field. Silver nanoparticles (AgNPs) are one of the promising novel nano-antibiotics. In the present study, AgNPs were synthesized using cell-free extract of Acinetobacter sp. challenged with silver nitrate. Preliminary observations done using UV-Vis spectrophotometry at 420 nm. Complete reduction of silver ions to AgNPs was confirmed through cyclic voltammetry. Electron microscopy revealed formation of spherical shaped nanoparticles of size upto 20 nm. These AgNPs were furthr used to determine their effect on activity of various antibiotics against pathogenic bacteria such as Neisseria and Xanthomonas. Higher antibacterial activity of AgNPs was observed against Gram-negative bacteria. Enhanced antibacterial action of AgNPs was observed with selected beta-lactam antibiotics producing upto 3-fold increase in area of zone of inhibition. On exposure to AgNPs, the minimum inhibitory concentration and minimum bactericidal concentration of antibiotics were lowered by upto 2000 times indicating potential synergistic action of AgNPs. This study clearly signifies that the drug, proved to be inefficient due to bacterial resistance, could be made functional again in presence of AgNPs. This will help in development of novel antibacterial formulations containing antibiotics and nanoparticles to combat multiple drug-resistance in microorganisms.
Farah Zulkifli,
Volume 21, Issue 2 (6-2024)
Abstract
Researchers are increasingly focusing on green synthesis methods for silver nanoparticles due to their cost-effectiveness and reduced environmental impact. In this study, we utilized an edible bird's nest (EBN), a valuable economic resource, as the primary material for synthesizing silver nanoparticles using only water as the solvent. Metabolite profiling of the EBN extract was conducted using LC-QTOF-MS in positive mode (ESI+), revealing the presence of lipids, glycosides, peptides, polysaccharides, and disaccharides. Upon the addition of silver nitrate to the aqueous EBN extract, noticeable color changes from transparent to brown indicated the successful formation of AgNPs. Subsequent characterization of these silver nanoparticles involved UV-Visible spectroscopy, which revealed an absorption peak at 421 nm. Further characterization was carried out using FESEM, ATR-FTIR spectroscopy, and EDX analysis. The involvement of phenolic agents, proteins, and amino acids in reducing the silver particles was confirmed. The synthesized nanoparticles exhibited a spherical shape, and a particle size ranging from 10 to 20 nm. The presence of elemental silver was confirmed by a strong, intense peak around 3 keV in the EDX spectrum. To assess their potential, the antibacterial properties of the silver nanoparticles against Escherichia coli and Staphylococcus aureus were evaluated using the agar diffusion method.
