Shape Of AgNPs Research Articles

Biosynthesis of Silver Nanoparticles by Polysaccharide of Leucaena leucocephala Seeds and Their Anticancer, Antifungal Properties and as Preservative of Composite Milk Sample

The AgNPs were synthesized using water-soluble polysaccharides extracted from the Leucaena leucocephala seeds. The UV-visible spectrum of the AgNPs showed a sharp absorption peak at 448 nm. The XRD analysis showed four major peaks of the crystalline AgNPs with planes of a face-centered cubic lattice of silver. The EDS spectrum showed a strong signal peak at ~3 keV. TEM and SEM observations showed the spherical shape of AgNPs with no particle agglomeration, and the size ranged from 8 to 20 nm. AgNPs were highly stable at -14.2 mV by zeta potential measurement. AgNPs showed significant anticancer activity against the cell lines of breast cancer, liver carcinoma, and colon carcinoma with the I C 50 value of 22.5, 12.3, and 8.9 μg mL-1, respectively. AgNPs at 900 μg mL-1 exhibited considerable antifungal activity against ten fungal pathogens. Water-soluble polysaccharide has the ability to synthesize AgNPs keeping strong antitumor, antifungal activities. The AgNPs can slow down spoilage of composite milk samples at different temperatures. In addition, the accuracy of milk-IR-analyses was not affected by different concentrations of AgNPs.

Macrolepiota-mediated synthesized silver nanoparticles as a green corrosive inhibitor for mild steel in re-circulating cooling water system.

A simple, cost effective and eco-friendly silver nanoparticle (AgNPs) was synthesized by wild edible Macrolepiota mushroom. Nanoparticles were characterized by UV-visible, FTIR, XRD analysis and TEM analysis. The characterized studies confirmed the spherical shape of AgNPs with 20-50nm size. Biocorrosion efficacy of myco-synthesized AgNPs and the mushroom extract were tested against mild steel by corrosive bacteria Bacillus thuringiensis EN2, Terribacillus aidingensis EN3 and Bacillus oleronius EN9. Weight loss analysis, EIS, and surface analysis were used to evaluate the corrosion inhibition efficiency of mild steel in various experimental systems. Reduced corrosion rate (0.07mm/y, 0.14mm/y), reduced weight loss (0.006 ± 2, 0.011 ± 2) and increased corrosion inhibition efficiency (59%, 18%) were identified in both system II and system IV. Peak intensity was reduced in both surface analysis studies (FTIR and XRD) in the presence of mushroom extract and AgNPs. EIS studies reveal that the mushroom extract and AgNPs act as a corrosive green inhibitor and adsorbs on the mild steel surfaces in cooling water tower system, which are responsible for corrosion protection.

Characterization of Talaromyces islandicus–mediated silver nanoparticles and evaluation of their antibacterial and anticancer potential

The biosynthesized silver nanoparticles (AgNPs) have been reported to possess several therapeutic applications. Silver is one of the important metals known for its bioactive properties not only as macromolecule but also as nanoparticle (NP). The current research focused on the eco-friendly synthesis of Talaromyces islandicus VSGF1(Lab code) -mediated AgNPs. The aqueous culture filtrate of T. islandicus VSGF1 was used as a reducing agent. The formation of AgNPs was confirmed by observing the color change from colorless to colloidal earthy-colored and a sharp absorption peak of ultraviolet-visible (UV-vis) spectroscopy at 400 nm. Fourier-transform infrared spectroscopy revealed the involvement of various functional groups for the formation and stabilization of AgNPs. The structure, size, and shape of mycosynthesized AgNPs were identified by X-ray diffraction (XRD), scanning electron microscopy, and atomic force microscopy (AFM) analysis. The XRD analysis exhibited crystalline nature of NPs whereas AFM analysis revealed the spherical shape of AgNP with average size range between 13 and 66 nm. The antibacterial activity of AgNPs (50 μg/ml) investigated against gram-positive and gram-negative bacteria revealed maximum zone of inhibition (ZOI) against drug-resistant Enterococcus faecalis MTCC439 (18.66 ± 0.57 mm) and Pseudomonas aeruginosa MTCC96 (16 ± 0 mm) followed by Staphylococcus aureus MTCC96 (15.33 ± 0.57 mm), Bacillus subtilis MTCC441 (14.66 ± 0.57 mm), and Escherichia coli MTCC45 (14.66 ± 0.57 mm). Further, the AgNPs evaluated for antitumor activity against human hepatocellular carcinoma (HepG2) cell line exhibited promising result with half-maximal inhibitory concentration (MIC) value at 38.17 μg/ml concentration through MTT (methylthiazolyl tetrazolium assay) assay. Apparently, this is the first report from T. islandicus to the best of our knowledge.

Effect of Phytofabricated Silver Oxide Nanoparticles on Wound Pathogens

Infection control is a challenging task in the treatment of wounds and a rise in antimicrobial resistance wound pathogens which is a barrier for the wound regeneration rapidly. Therefore, there is an urgent requirement of novel antimicrobial agents to target the wound pathogens and their biofilms. Silver nanoparticles (AgNPs) are the predominant antimicrobial agent for wound treatment due to their broad spectrum antimicrobial potential against various wound pathogens. Silver nanoparticles (AgNPs) were prepared from aqueous Adenanthera pavonina seed extract. This extract plays as a reducing agent for reduction of silver nitrate to silver oxide nanoparticles. An absorption peak at 428 nm with characteristic feature of surface plasmon resonance was observed. The average size of AgNPs was found to be ~200 nm and cube in shape of AgNPs. FTIR data revealed the presence of phenolic groups that were responsible for reduction and stabilization of silver nanoparticles. Face centered cubic (FCC) crystalline structure was revealed from XRD relating to silver oxide (AgO) with good antibacterial potential. The antioxidant activity of extract increases when the concentration increases, and it can be used in the inhibition of free radicals at wound site. Antibacterial activities showed effective inhibition against various pathogens such as E.coli, Salmonella typhi, Sphingomonas, and Bacillus. Given this correspondence, the green synthesized AgNPs would be a potential antimicrobial agent for various wound treatments.

PLANT MEDIATED GREEN AND FACILE SYNTHESIS OF SILVER NANOPARTICLES AND THEIR POSSIBLE APPLICATION AS ANTIMICROBIAL AGENTS

In recent year green and eco-friendly synthesis of metal nanoparticles plays an important role in nanotechnology, medical science, industries, ceramics etc. The manuscript focuses on the green and facile synthesis of AgNPs from aqueous solution of leaf of Cassia fistula. UV-Visible spectra confirm the bio-formation of AgNPs at 412 nm with the witness of change in colour. Synthesized silver nanoparticle characterized further by FTIR, SEM, EDX and XRD spectroscopic technique. The shape of AgNPs is observed to be like oval, triangular and cylindrical respectively. EDX analysis confirmed the elemental percentage of silver 93.02%. FTIR shows shifting in bands from lower side to upside.The biosynthesized AgNPs shows antibacterial activity against E. coli and B. subtilis pathogens and it was found that AgNPs were more effective against E. coli and B. subtilis bacteria. The method used in this study for the biosynthesis of AgNPs from aqueous extracts of Cassia Fistula was green, reduce harmful chemical with no environmental hazards.

Catalytic activity of silver nanoparticles synthesized using Crinum asiaticum (Sudarshan) leaf extract

Synthesizing silver nanoparticles (Ag-NPs) from the green route has been gaining momentum in recent years since it is an eco-friendly, cost-efficient, non-toxic and straightforward use of precursors. The study presents a green route to synthesize Ag-NPs using green leaves of Crinum asiaticum and examines how biomolecules present in Crinum asiaticum lead to the formation of Ag-NPs. Biosynthesized Ag-NPs were confirmed, and the effect of varying pH, reaction temperature and plant extract concentration on the reduction of silver ions was observed. Ag-NPs exhibit an absorption peak at around 449 nm due to surface plasmon resonance. The size, morphology, crystalline structure and stability of Ag-NPs were examined using different techniques like absorption spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and zeta potential analysis. The shape of Ag-NPs was spherical and the average particle size was about 11 nm. Appreciable catalytic properties of Ag-NPs were also ascertained by reducing a toxic dye like methylene blue (MB) in the presence of NaBH4 with a rate constant of 0.097 min−1.

Mosquito larvicidal potential of Solanum xanthocarpum leaf extract derived silver nanoparticles and its bio-toxicity on non-target aquatic organism.

Mosquitoes are insects of public health importance that act as a vector to transmit various vector-borne diseases in humans including dengue, malaria, filariasis and yellow fever. The continually employed synthetic insecticides have developed resistance in mosquitoes. Nano-based botanical insecticides can be considered as the best alternative due to several advantages like being simple, non-pathogenic, biodegradable and safe to the environment. The present work reported the maximum larvicidal potential of green synthesized silver nanoparticles (AgNPs) derived from the leaf extract of Solanum xanthoearpum against the third instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus over its crude leaf extract. The synthesis of AgNPs was done by adding leaf extract into silver nitrate solution in a conical flask. The characterization of AgNPs was done using different techniques such as UV-Vis, SEM, TEM, XRD, DLS and SAED. FT-IR analysis was done to find out the compound responsible for bio-reduction of silver nitrate. Larvicidal activity of AgNPs was checked against An. stephensi, Ae. aegypti, and Cx. quinquefasciatus according to WHO standard protocol and toxicity was evaluated against Poecilia reticulate. A change in colour was observed indicating the synthesis of AgNPs which was further confirmed by a strong surface plasmon resonance peak at 421nm under the UV-Vis spectrum. SEM and TEM micrographs exhibited that the most common shape of AgNPs was spherical. XRD spectrum showed crystalline nature of silver nanoparticles. FT-IR spectrum showed the presence of various functional groups such as carboxyl and hydroxyl which might be responsible for bio-reduction and capping of silver nanoparticles. Further, silver nanoparticles were very effective against An. stephensi, Ae. aegypti, and Cx. quinquefasciatus with LC50 and LC90 values of 1.90, 2.36, 2.93, 3.82, 4.31 and 7.63 ppm, respectively, as compared to aqueous leaf extract after 72 h of exposure and were non-toxic against non-target organism P. retieulata. Interpretation & eonelusion: From the above finding, it can be concluded that fabricated AgNPs can be promising eco-friendly tools for controlling mosquito vectors.

Green Synthesis of Silver Nanoparticles from Alhagi graecorum Leaf Extract and Evaluation of Their Cytotoxicity and Antifungal Activity

Green synthesis of silver nanoparticles (AgNPs) using different plant parts has shown a great potential in medicinal and industrial applications. In this study, AgNPs were in vitro green synthesized using A. graecorum, and its antifungal and antitumoractivities were investigated. Scanning electron microscopy (SEM) image result indicated spherical shape of AgNPs with a size range of 22‐36 nm indicated by using Image J program. The functional groups indicated by Fourier‐transform infrared spectroscopy (FTIR) represented the groups involved in the reduction of silver ion into nanoparticles. Alhagi graecorum AgNPs inhibited MCF‐7 breast cancer cell line growth in increased concentration depend manner, significant differences shown at 50, 100, and 150 μg/ml concentrations compared to the control. Strong antifungal activity against Candida species (C. albicans., C. glabrata, C. parapsilosis, C. tropicales, and C. krusei) was observed and the inhibition zone range from 14‐22 mm at a concentration of 0.01 mmol/ml and from 17‐27 mm at a concentration of 0.02 mmol/ml. Based on our findings, it is concluded that synthesized silver nanoparticles from A. graecorum can be used as a potential antitumor and antifungal agent for various therapeutical applications.

Biosynthesis, characterization, and evaluation of antibacterial and photocatalytic methylene blue dye degradation activities of silver nanoparticles from Streptomyces tuirus strain

Silver nanoparticles (AgNPs) are a promising technology for the design of antimicrobial agents against drug-resistant pathogens. It could also be used for the photocatalytic degradation of dyes used in industries such as methylene blue (MB). In this study, 17 different actinomycetal strains isolated from hydrocarbon-contaminated soils collected from an oil distribution company in Algeria were evaluated for their ability to produce NPs. After a selection process, S16 was the main strain capable of synthesizing AgNPs extracellularly. The strain S16 was determined using molecular identification based on the sequencing of the 16S rDNA gene. Among various techniques used for the synthesis of AgNPS, a technique using a temperature of 30 °C, pH of 7, a metal salt concentration of 1 mM, and a period of 72 h in the dark were found to be more effective in the biosynthesis of the AgNPs. The biosynthesized AgNPs that were analyzed by UV–visible spectroscopy resulted in a specific peak at a wavelength of (λ = 400 nm). The DRX analyses showed characteristic peaks of the AgNPs at (1 1 1), (2 0 0), (2 2 2), and (3 1 1), which validated the presence and crystalline nature of the biosynthesized NPs. Zetasizer analysis showed an average size and zeta potential of 64 nm (−32.3 mV), while the SEM-EDS analysis confirmed the spherical shape of AgNPs and the presence of Ag atoms in the elemental composition. The biosynthesized AgNPs indicated adequate antibacterial activity against 5 out of the 6 strains tested in this study, using minimum inhibitory concentration (MIC) that ranged from 217.18 μg/mL to 1137.5 μg/mL. The AgNPs were combined with commercial antibiotics and the synergistic effect of the combination was also assessed against MRSA which resulted in increased antibacterial activity of AgNPs in the presence of the strain S16. Furthermore, the photocatalytic degradation of the methylene blue (MB) was evaluated under sunlight and UV irradiations using biosynthesized AgNPs. The AgNPs showed photocatalytic decolorization potential of 71.3% for MB dye (20 ppm) under sunlight irradiation within 6 h of incubation, while only 11.25% of the MB dye degraded using UV irradiation.

Antitumor Activities of Biosynthesized Silver Nanoparticles using Dodonaea viscosa (L.) Leaves Extract

Biosynthesis of silver nanoparticles (AgNPs) from plant extracts is considered one of the green chemistry methods, as this method is characterized by ease, fast and low cost to manipulate. Interestingly, AgNPs have an important role, especially in nano-medicine. Using AgNPs for cancer therapy are an affordable way to control tumor growth and constitute a choice strategy to fight cancer cells. First type of conventional cancer treatment is surgical treatment then radiation and chemotherapy. However, these treatments may work for some cancer subtypes, and have various side effects, in most cases, with high doses. In this study, silver nanoparticles (AgNPs) were biosynthesized using Dodonaea viscosa leaves extract. The formation of these particles was confirmed through the color change, UV-Visible Spectrophotometer displaying at 463nm.While the particles characterization was done by Surface Plasmon Resonance (SPR) band and Fourier Transform Infra-Red (FT-IR) spectroscopy which revealed the effective functional groups that have ability to bio-reduction silver ion Ag+. In addition, X-ray diffraction (XRD) determined the crystal structure of silver nanoparticles, as shown by the peaks at 2θ values of 38.1874, 46.2491, 57.5409 and76. 8313ο.The atomic force microscopy (AFM) analysis showed the size and the surface properties of biosynthesized nanoparticles, and the silver nanoparticles had an average size of 60.22 nm. Finally, scanning electron microscopy (SEM) showed spherical shape of AgNPs and having different average diameter D1 (21.10), D2 (21.39) and D3 (11.86) nm. In vitro, the synthesized AgNPs exhibited potential anti-tumor activities against human lung cancer (A549) and ovarian cancer (SK-OV-3) carcinoma cell lines in a dose-dependent manner with IC50 of 1.73 and 2.23µg.ml-1, respectively. Our results showed the promising use of AgNPs as an alternative treatment for cancer cells directly and selectively on A549 cell line at concentrations (2.000, 1.699, 1.398 and 1.301 μg /mL).

Solar radiation-induced synthesis of bacterial cellulose/silver nanoparticles (BC/AgNPs) composite using BC as reducing and capping agent.

In the present work, a simple, novel, and ecofriendly method for synthesis of silver nanoparticles (AgNPs) and BC/AgNP composite using bacterial cellulose (BC) nanofibers soaked in AgNO3 solution under induction action of solar radiation. The photochemical reduction of silver Ag + ions into silver nanoparticles (Ago) was confirmed using UV visible spectra; the surface plasmon resonance of synthesized AgNPs was localized around 425nm. The mean diameter of AgNPs obtained by DLS analysis was 52.0nm with a zeta potential value of -9.98mV. TEM images showed a spherical shape of AgNPs. The formation of BC/AgNP composite was confirmed by FESEM, EDX, FTIR, and XRD analysis. FESEM images for BC showed the 3D structures of BC nanofibers and the deposited AgNPs in the BC crystalline nanofibers. XRD measurements revealed the high crystallinity of BC and BC/AgNP composite with crystal sizes of 5.13 and 5.6nm, respectively. BC/AgNP composite and AgNPs exhibited strong antibacterial activity against both Gram-positive and Gram-negative bacteria. The present work introduces a facile green approach for BC/AgNP composite synthesis and its utility as potential food packaging and wound dressings, as well as sunlight indicator application.

High diversity of microalgae as a tool for the synthesis of different silver nanoparticles: A species-specific green synthesis

Autotrophic microorganisms can be useful for the green synthesis of nanoparticles (NPs), but there is a lack of knowledge to affirm if the high variety of microorganisms is connected to a potential high diversity of NPs. Here, aqueous extracts of two cyanobacteria (Synechococcus elongatus and Microcystis aeruginosa) and four microalgae (the chlorophytes Coelastrum astroideum and Desmodesmus armatus; and the charophytes Cosmarium punctulatum and Klebsormidium flaccidum) were used for the biosynthesis of silver nanoparticles (AgNPs). The nanoparticle characterization was performed by UV–Visible absorption spectrum, Fourier Transforms Infrared (FT-IR), Transmission Electron Microscopy (TEM) and Energy Dispersive X-Ray Spectroscopy (EDS). This is the first study trying to establish some connection between the taxonomical diversity of microalgae and cyanobacteria and the synthesis of different silver nanoparticles. All algal and cyanobacterial extracts resulted in the synthesis of well-disperse and crystalline AgNPs, with no agglomerate formation. TEM analysis showed spherical AgNPs shape with size range within 1.8–5.4 nm. FTIR analysis demonstrated the presence of hydroxyl groups of peptidoglycan nature acting as stabilizing agents in the surface of the AgNPs. The nanoparticle shape and kind of stabilizing biomolecules were highly similar, but their size was significantly different, which can affect the NP properties. There was no pattern for the AgNPs in terms of the microorganism phyla. Our results showed a very high potential for the use of cyanobacteria and microalgae in the green synthesis of NPs since the variety of AgNPs obtained was species-specific.

Effect of green synthesized silver nanoparticles on optical behavior of feldspathic porcelain

In this study, pomegranate peel extract (PPE) was used for the green synthesis of silver nanoparticles (AgNPs). The AgNPs were characterized by X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM). TEM micrograph showed the spherical shape of AgNPs sized between 30 and 50 nm. XRD confirmed the face-centered cubic (FCC) crystalline structure of AgNPs. The antibacterial activity and cellular toxicity of the modified porcelain with AgNPs were also studied. The results of biocompatibility of modified porcelain with AgNPs revealed that samples decreased the viability of L929 cells and after treatment with AgNPs samples antibacterial activity was significantly increased. The effect of AgNPs on the optical behavior (color change (ΔE), contrast ratio (CR), and translucency parameter (TP)) of feldspathic porcelain was investigated by clinical spectrophotometer. It was shown that addition of AgNPs to feldspathic porcelain significantly increased the TP and decreased the CR compared to the control group. The results of this study indicate that addition of AgNPs up to 500 µg/mL AgNPs to VitaVM9 feldspathic porcelain did not cause the clinically recognizable threshold color change (ΔE = 2.69) and increases the ceramic translucency.

Larvicidal and antioxidant activity of green silver nanoparticles synthesized using Musa acuminate peel extract against Aedes aegypti

The present study pertains to the exploitation of biowaste generated through Banana (Musa acuminate L.) peels for the synthesis of green silver nanoparticles (AgNPs) and their bioactivity was evaluated for managing the dengue vector, Aedes aegypti. UV-VIS specrtophotometery was used for confirming AgNPs synthesis and a peak was observed at 426 nm. Characterization of AgNPs was done using Scanning electron microscopy which depicted spherical shape of AgNPs while Transmission electron micrographs revealed their size to be ranging from 20 to 50 nm. AgNPs bioactivity was studied against III instar larvae following 24, 48 and 72 h exposure and values of LC50 and LC90 were analyzed using probit analysis. LC50 values ranged from 10.69 to 25.15 ppm with AgNPs at various time exposures. Antioxidant potential of these AgNPs was also evaluated to supplement these findings. This study highlights the potential of biowastes as a potent larvicide against Aedes aegypti.

Physicochemical properties and antimicrobial activity of nanocomposite films based on carboxymethylcellulose and silver nanoparticles

AbstractSilver nanoparticles (AgNPs) stabilized by sodium carboxymethylcellulose (Na‐CMC) with degree of substitution (DS) 0.65‐0.90 and degree of polymerization (DP) 200‐600 were synthesized by photochemical method. The structural, physico‐chemical, and physico‐mechanical properties as well as antimicrobial activity of polymer films containing the Na‐CMC and AgNPs were studied. The shape, quantity, and size of the AgNPs embedded into the Na‐CMC films were determined by UV‐Vis spectroscopy, ZETASIZER Nano ZS, atomic force microscopy and transmission electron microscopy. It was found that the increase of silver nitrate concentration in solution of Na‐CMC followed by photoirradiation leads to the change of size and shape of AgNPs. The AgNPs in the range of size from 5 to 35 nm were found to enhance the microbicidal activities of the Na‐CMC films.

Green synthesis of silver nanoparticles from Eriobotrya japonica extract: a promising approach against cancer cells proliferation, inflammation, allergic disorders and phagocytosis induction

Nanoparticles (NPs) have biological activities like antibacterial, antifungal, drug delivery, immunomodulation and antitumor activities. The aim of the current study was to investigate some of biomedical applications of silver NP synthesis using extracts from leaves of Eriobotrya japonica. Colour changes, UV–visible spectroscopy, SEM, zeta potential, dynamic light scattering, FTIR and XRD were used to confirm AgNPs formation. The UV–vis spectrum absorption band was observed at almost 430 nm. The SEM image shows quasi-spherical shape of AgNPs. The zeta potential demonstrated the negative surface charge of NPs. FTIR results showed the functional groups of AgNPs. Crystalline nature of AgNPs was confirmed by XRD pattern. MTT assay was used to study the anti-proliferative activity against MCF-7 and HeLa cells. Apoptosis was tested using a DNA-fragmentation test, and expression of P53. AgNPs inhibited the proliferation of MCF-7 and HeLa cells, and reduced inflammation. Treatment with AgNPs significantly decreased allergic disorder. AgNPs stimulated the phagocytosis process in BMDMs. The results suggested that AgNPs could be a promising therapy for future and preventing inflammation, reduce allergic disorders and prevent bacterial infection through the up-regulation of phagocytosis. Hence, future work such as developed and improved NPs as adjuvants, immune-modulating substances and nano-drug delivery system is needed.

Ecofriendly Synthesis of Silver Nanoparticles by Terrabacter humi sp. nov. and Their Antibacterial Application against Antibiotic-Resistant Pathogens

It is essential to develop and discover alternative eco-friendly antibacterial agents due to the emergence of multi-drug-resistant microorganisms. In this study, we isolated and characterized a novel bacterium named Terrabacter humi MAHUQ-38T, utilized for the eco-friendly synthesis of silver nanoparticles (AgNPs) and the synthesized AgNPs were used to control multi-drug-resistant microorganisms. The novel strain was Gram stain positive, strictly aerobic, milky white colored, rod shaped and non-motile. The optimal growth temperature, pH and NaCl concentration were 30 °C, 6.5 and 0%, respectively. Based on 16S rRNA gene sequence, strain MAHUQ-38T belongs to the genus Terrabacter and is most closely related to several Terrabacter type strains (98.2%–98.8%). Terrabacter humi MAHUQ-38T had a genome of 5,156,829 bp long (19 contigs) with 4555 protein-coding genes, 48 tRNA and 5 rRNA genes. The culture supernatant of strain MAHUQ-38T was used for the eco-friendly and facile synthesis of AgNPs. The transmission electron microscopy (TEM) image showed the spherical shape of AgNPs with a size of 6 to 24 nm, and the Fourier transform infrared (FTIR) analysis revealed the functional groups responsible for the synthesis of AgNPs. The synthesized AgNPs exhibited strong anti-bacterial activity against multi-drug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 6.25/50 and 12.5/50 μg/mL, respectively. The AgNPs altered the cell morphology and damaged the cell membrane of pathogens. This study encourages the use of Terrabacter humi for the ecofriendly synthesis of AgNPs to control multi-drug-resistant microorganisms.

Effect of electrolyte pH value and current density on the electrodeposition of silver nanoparticles into porous silicon

Nanostructured porous silicon (PS) can be used as a template for the growth of noble metal nanoparticles for the subsequent development of metal/semiconductor hybrid structures with application in several fields. The current work reports on the electrodeposition of silver nanoparticles (AgNPs) into columnar PS layers. In particular, the size, morphology, and surface density of the AgNPs grown into PS were studied as a function of the electrolyte pH value and the infiltration current density. Furthermore, the optical properties of the hybrid PS + AgNPs structures were analyzed. The experimental results show a remarkable reduction in the size of AgNPs and increased growth rate upon reducing the acidity of the electrolyte and upon increasing the current density. In addition, a remarkable reduction of the average reflectance is observed under specific fabrication conditions. In particular, as the pH values of the electrolyte increase, the optical reflectance decreases. This relation is attributed to the reduction in the AgNPs size. On the other hand, increasing the infiltration current density increases the average reflectance due to increasing surface density of the AgNPs. These results demonstrate that the size and shape of AgNPs can be controlled by adjusting the applied infiltration current density and the pH value of the electrolyte depending on the intended application.

Polyacrylamide hydrogels doped with different shapes of silver nanoparticles: Antibacterial and mechanical properties

The incorporation of nanoparticles into a hydrogel matrix enables the development of innovative smart materials with enhanced biophysical properties. In this proof-of-concept study, we encapsulated different shapes (spherical, triangular and rod) of silver nanoparticles (AgNPs) within a hydrogel matrix of polyacrylamide (PAA) and N-methylenebisacrylamide (MBA) (PAA-MBA) to investigate whether these hydrogels exhibited shape-dependent antimicrobial and mechanical properties. We examined the mechanism of adsorption of different shapes of AgNPs using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Results showed that the adsorption of AgNPs was primarily occurring on the surface/outer pores of the PAA-MBA hydrogel and that rod AgNPs demonstrated a relatively slower adsorption within the hydrogel matrix. The mechanical properties of AgNP-doped hydrogels were evaluated using rheology and atomic force microscopy (AFM) quantitative imaging. We observed a higher storage and Young’s modulus which proved that the incorporation of the various shapes of AgNPs increased the mechanical properties of the hydrogels with no significant differences between the different shapes. While both spherical and triangular AgNP-doped hydrogels showed strong antimicrobial activity, the hydrogel with the rod AgNPs had a relatively lower antimicrobial activity. Overall, our preliminary results demonstrated that nanocomposite hydrogels were promising materials for applications in the future development of wound dressings.

Biomedical and photocatalytic applications of biosynthesized silver nanoparticles: Ecotoxicology study of brilliant green dye and its mechanistic degradation pathways

The preparation of nanoparticles from biological materials is an economic and environmentally friendly strategy with several advantages. The current study is focused to synthesize silver nanoparticles using Petroselinum crispum plant extract. Various characteristics of biologically synthesized AgNPs were determined with UV–Visible (UV/Vis) Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, and High-Resolution Transmission Electron Microscopy (HRTEM). The plasmonic resonance peak at 425 nm ensured the formation of AgNPs. The FTIR analysis showed that the as-synthesized particles contain alcoholic and polyphenolic constituents, which are responsible for their capping and reduction. The HRTEM results revealed spherical shape of AgNPs with size ranging from 25 to 90 nm. The as-synthesized particles demonstrated excellent antibacterial properties against Gram positive and Gram-negative bacteria. The antioxidant applications of the particles were determined with 2,2-diphenyle-1-picrylhydrazyl (DPPH). Moreover, the photocatalytic application of the synthesized AgNPs was evaluated for brilliant green dye (BG). The results demonstrated high degradation of BG due to small size and well-dispersed nature of AgNPs. Degradation products of BG were identified to suggest degradation pathways. The eco-toxicity of the BG and constituents derived from the dye were studied with Ecological Structure Activity Relationship (ECOSAR) software.