Benign nano-assemblages of silver induced by β galactosidase with augmented antimicrobial and industrial dye degeneration potential (original) (raw)
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The morphology of silver nanoparticles prepared by enzyme-induced reduction
Beilstein Journal of Nanotechnology, 2012
Silver nanoparticles were synthesized by an enzyme-induced growth process on solid substrates. In order to customize the enzymatically grown nanoparticles (EGNP) for analytical applications in biomolecular research, a detailed study was carried out concerning the time evolution of the formation of the silver nanoparticles, their morphology, and their chemical composition. Therefore, silvernanoparticle films of different densities were investigated by using scanning as well as transmission electron microscopy to examine their structure. Cross sections of silver nanoparticles, prepared for analysis by transmission electron microscopy were additionally studied by energy-dispersive X-ray spectroscopy in order to probe their chemical composition. The surface coverage of substrates with silver nanoparticles and the maximum particle height were determined by Rutherford backscattering spectroscopy. Variations in the silver-nanoparticle films depending on the conditions during synthesis were observed. After an initial growth state the silver nanoparticles exhibit the so-called desert-rose or nanoflower-like structure. This complex nanoparticle structure is in clear contrast to the auto-catalytically grown spherical particles, which maintain their overall geometrical appearance while increasing their diameter. It is shown, that the desert-rose-like silver nanoparticles consist of single-crystalline plates of pure silver. The surface-enhanced Raman spectroscopic (SERS) activity of the EGNP structures is promising due to the exceptionally rough surface structure of the silver nanoparticles. SERS measurements of the vitamin riboflavin incubated on the silver nanoparticles are shown as an exemplary application for quantitative analysis.
3 Biotech, 2020
The present study describes green synthesis of silver nanoparticles (AgNPs) and inulin hydrolyzing enzyme nanocomplexes (ENC) using Azadirachta indica (Ai) and Punica granatum (Pg) leaf extracts. Surface topology and physico-chemical characteristics of AgNPs were studied using surface plasmon resonance (SPR), FTIR, SEM, AFM and EDX analyses. Particle size analysis using dynamic light scattering and AFM studies revealed that Ai-AgNPs (76.4 nm) were spherical in shape having central bigger nano-regime with smaller surroundings while Pg-AgNPs (72.1 nm) and ENCs (Inulinase-Pg-AgNPs ~ 145 nm) were spherical particles having smooth surfaces. Pg-AgNPs exhibited significant photocatalysis of a thiazine dye, methylene blue. Both Ai-and Pg-AgNPs showed selective antibacterial action by inhibiting pathogenic Bacillus cereus, while the probiotic Lactobacillus strains remained unaffected. Ai-AgNPs showed potential anti-biofilm effect (30% viability) on B. cereus biofilms. Pg-AgNPs showed anti-cancer effect against human colon cancer cell lines (Caco-2) resulting in 40% cell death in 48 h. Enzymes (inulinase, L-asparaginase and glucose oxidase) were successfully immobilized onto nanoparticles together with the biogenic synthesis of AgNPs and recyclability of the Inulinase-Pg-AgNPs complex was demonstrated. The study elaborates characteristics of green synthesized nanoparticles and their potential applications as anti-cancer, antibacterial and antioxidant nano drugs that could be used in food and nutraceutical industries. Enzyme immobilization on AgNPs without any toxic cross-linker opens up newer possibilites in enzyme-nanocomplex research.
Biological Sciences SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES
2014
Silver nanoparticles exhibit new optical properties, which are observed neither in molecules nor in bulk metals. In the present study silver nanoparticle colloid was produced by chemical reduction method of silver salt (silver nitrate AgNO3) solution. The silver nanoparticles were characterized by using UV-VIS spectrometer and Scanning Electron Microscope (SEM). The Surface Plasmon Resonance peak in absorption spectra of silver colloidal solution showed an absorption maximum at 450 nm which indicated formation of silver nanoparticles. The size range 44nm to 56.55nm of silver nanoparticles was determined by using Scanning Electron Microscope (SEM). The absorbance range of prepared silver nanoparticles solution was checked on 1 st day, 5 th day, 18 th day and on 30 th day. There was no obvious change observed in peak position for 30 days, depicting the stability of Silver nanoparticles.
International Journal of Environmental Research and Public Health, 2013
Our research focused on the production, characterization and application of silver nanoparticles (AgNPs), which can be utilized in biomedical research and environmental cleaning applications. We used an environmentally friendly extracellular biosynthetic technique for the production of the AgNPs. The reducing agents used to produce the nanoparticles were from aqueous extracts made from the leaves of various plants. Synthesis of colloidal AgNPs was monitored by UV-Visible spectroscopy. The UV-Visible spectrum showed a peak between 417 and 425 nm corresponding to the Plasmon absorbance of the AgNPs. The characterization of the AgNPs such as their size and shape was performed by Atom Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques which indicated a size range of 3 to 15 nm. The anti-bacterial activity of AgNPs was investigated at concentrations between 2 and 15 ppm for Gram-negative and Gram-positive bacteria. Staphylococcus aureus and Kocuria rhizophila, Bacillus thuringiensis (Gram-positive organisms); Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium (Gram-negative organisms) were exposed to AgNPs using Bioscreen C. The results indicated that AgNPs at a concentration of 2 and 4 ppm, inhibited
Biosynthesis and Characterization of Silver Nanoparticles
Research Square (Research Square), 2022
In this study, a quick, simple, cost-e cient, and green procedure for silver nanoparticles (AgNPs) biosynthesis was executed at 25°C using 5 easily accessible plants from Cameroon including Carica papaya, Achillea millefolium, Perilla frutescens, Ocimum gratissimum, and Garcinia kola. These plants served as capping and reducing agents, while the AgNO 3 salt was the precursor. Initially, bioreduction of metallic Ag + to Ag 0 nanoparticles was established via a reduction in pH. Biosynthesis of AgNPs was primarily a rmed visually via a color change of the reaction mixtures with the ultraviolet-visible (UV-Vis) spectroscopy absorption peaks demonstrating that the synthesized particles were indeed AgNPs. X-ray diffractometry (XRD) showed the nanoparticles were crystalline in nature and had negative zeta potential (ζ-potential) values, which indicate they could be naturally stable. The phytochemical and Fourier transform infrared (FTIR) spectroscopic analyses revealed the possible phytochemicals in each aqueous plant extract responsible for reducing the Ag + metallic ions to nanoparticles followed by capping and stabilization of the nanoparticles. The high-resolution transmission electrons microscopy (HRTEM) micrographs revealed nanoparticles of varying shapes and sizes. Also, micrographs from the scanning electron microscopy (SEM) showed clouds of polydispersed nanoparticles, which were con rmed by energy dispersive X-ray (EDX) spectroscopy to be highly composed of Ag, with strong optical peaks around 3 kV. The results thus validate that these AgNPs can be e ciently formulated using easily available tropical plants for safe applications in various sectors such as medicine and agriculture.
Journal of Applied Pharmaceutical Science, 2018
Biosynthesis of nanoparticles is the important area in applicable nanoparticles and development of nanobiotechnology. In this present investigation, we used soil bacteria Proteus sp for the biosynthesis of silver nanoparticles. The synthesized nanoparticles were visually observed and characterized using UV-vis spectrophotometer for its surface plasmn resonance, crystalline nature was identified by X-ray diffraction assay and morphology was identified using scanning electron microscope. The peak at 430 nm in UV-vis spectroscopy confirms the SPR and XRD shows the intensity of (1 1 1) and (2 2 2) confirm the crystalline nature. The 50-100 nm sized and spherical shaped nanoparticles are synthesized was confirmed by SEM. The antibacterial activity of the silver nanoparticles analysed using agar well diffusion method, shows very good zone of inhibition equals to commercially available antibiotics.
Synthesis of silver nanoparticles used chemical reduction method by glucose as reducing agent
Journal of Physics: Conference Series, 2019
Silver nanoparticles have been successfully synthesized using a chemical reduction method at room temperature using glucose as a reducing agent, silver nitrate as a source of nitrate, polyvinyl alcohol (PVA) as a stabilizing agent. The purpose of this research was to determine the effect of the mole ratio of reducing agent Glu / Ag and percentage (%) PVA (b/v) in the silver nanoparticle synthesis of the resulted product. Product characterization was analyzed by UV-Vis Spectrophotometers, XRD, and TEM. The Analysis of the UV-Vis spectra showed that the most stable particles were silver nanoparticles used PVA 3% and Glu / Ag. 1: 8 on λmax 415 to 417 nm. TEM’s characterization showed that silver nanoparticles were spherical with a dominant size range of 12,28 nm – 38,45 nm nm. The newly synthesized silver nanoparticles may have a potential for antibacterial applications.
Bio-synthesis of silver nanoparticles with antibacterial activity
Materials Chemistry and Physics, 2019
Silver nanoparticles (Ag-NPs) have potential applications in life science, food chemistry, biomedicine, photocatalysis and cosmetics fields due to its unique optical, electrical and catalytic properties besides the strong antibacterial property. Apple pomace, a by-product of apple juice production, is ample and easily available. In the present study, this green raw material was used to biosynthesize Ag-NPs for the first time. The obtained silver nanoparticles were investigated by UV-vis, TEM, XRD, and FTIR, respectively. The results showed that the concentration of AgNO 3 and the volume ratio of AgNO 3 solution to apple pomace extract were the important factors affecting the synthesis of silver nanoparticles. When the concentration of AgNO 3 was 10 mmol/L, the volume ratio of AgNO 3 solution to the apple pomace extract of 4:1(ν/ν), Ag-NPs were quickly formed. They were stable with high degree of crystallinity. The particle sizes ranged between 10-20nm and the conversation of silver ions was up to 99%. The bacteriostatic circle tests revealed that the biosynthesized Ag-NPs had a strong antibacterial activity against gram positive bacteria and gram negative bacteria. FTIR analysis demonstrated that some bio-molecules with groups of-NH 2 ,-COOH and-OH were distributed on the surface of the newly synthesized Ag-NPs. During the synthesis of silver nanoparticles, there were not any poisonous reducers and stabilizers introduced.
Synthesis and characterization of silver nanoparticles
2007
Silver nanoparticles have received considerable attention due to their attractive physical and chemical properties. The surface plasmon resonance and large effective scattering cross section of individual silver nanoparticles make them ideal candidates for molecular labeling, where phenomena such as surface enhance Raman scattering (SERS) can be exploited. In addition, silver nanoparticles have recently been shown to be a promising antimicrobial material. In the present research silver colloid was produced by sodium citrate reduction. The colloidal silver was incorporated by dip-coating to the polymer substrate. X-Ray Fluorescence Spectroscopy (XRF), Atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-VIS ) and SERS indicate that the produced structures include metallic crystalline silver nanoparticles. The surface plasmon resonance peak in absorption spectra of silver particles showed an absorption maximum at 420-500 nm. The silver - polymer nanocomposites structures with selective light properties as a result of plasmon resonance shifting in the UV-VIS wavelength region were produced.
Biosynthesis of Green Silver Nanoparticles and Its UV-Vis Characterization
2020
In a recent time, silver nanoparticles (AgNPs) have attracted a lot of attention from researchers because of their special properties. In this paper green silver nanoparticles (AgNP) were synthetized from 2, 4 and 8 % w/v orange peel extracts. The synthesis was done by the process of chemical reduction in the presence of 1 mM silver nitrate (AgNO3) solution at 23 °C at 400 rpm for 6 hours. Orange peel extracts were used as capping agent to reduce 1mM solution to silver nanoparticles. The biosynthesized AgNPs were characterized by UVVis spectroscopy in the wavelength range from 300 to 600 nm with maximum of absorption at 460 nm. The results have shown that by increasing the concentration of peel extract increase the formation of silver nanoparticles. The advantage of this green method of synthesis is the use of fruit waste to create new valuable materials with potential antibacterial activity.