Biosynthesis Of AgNPs Research Articles

A review of the phytochemical mediated synthesis of AgNP (silver nanoparticle): the wonder particle of the past decade.

Silver nanoparticle (AgNP) has been one of the most commonly used nanoparticles since the past decade for a wide range of applications, including environmental, agricultural, and medical fields, due to their unique physicochemical properties and ease of synthesis. Though chemical and physical methods of fabricating AgNPs have been quite popular, they posed various environmental problems. As a result, the bioinspired route of AgNP synthesis emerged as the preferred pathway for synthesis. This review focuses extensively on the biosynthesis of AgNP-mediated through different plant species worldwide in the past 10 years. The most popularly utilized application areas have been highlighted with their in-depth mechanistic approach in this review, along with the discussion on the different phytochemicals playing an important role in the bio-reduction of silver ions. In addition to this, the environmental factors which govern their synthesis and stability have been reviewed. The paper systematically analyses the trend of research on AgNP biosynthesis throughout the world through bibliometric analysis. Apart from this, the feasibility analysis of the plant-mediated synthesis of nanoparticles and their applications have been intrigued considering the perspectives of engineering, economic, and environmental limitations. Thus, the review is not only a comprehensive summary of the achievements and current status of plant-mediated biosynthesis but also provides insight into emerging future research frontier.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13204-021-02135-5.

Photochemical synthesis of metallic silver nanoparticles using Pistacia khinjuk leaves extract (PKL@AgNPs) and their applications as an alternative catalytic, antioxidant, antibacterial, and anticancer agents

AbstractIn recent decades, antimicrobial resistance of different bacteria against various antibiotics and contamination of water resources by various dyes has been one of the most important human problems. Therefore, in this research, biogenic silver nanoparticles were synthesized using nontoxic and rapid approach using Pistacia khinjuk leaves extract (P. khinjuk) as compatible and safe reducing agent (PKL@AgNPs). Nanoparticle optimization experiments were performed at different times, temperatures and concentrations in order to achieve the most optimal conditions. The biosynthesized AgNPs were characterized in terms crystalline, morphology and structural. The Fourier‐transform infrared spectroscopy (FT‐IR) spectra showed that the phenol compounds present in the P. khinjuk leaves extract were responsible for silver ion (Ag+) reduction and stabilization of AgNPs (Ag0). X‐ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) analysis results revealed that the product were face‐centered cubic structure, homogeneous, uniformly, oval‐like and spherical morphology with size of about 35–45 nm. The biosynthesized AgNPs exhibited a high photocatalytic activity for the degradation of the methylene blue (MB) and methyl orange (MO) as hazardous contaminants. The degradation efficiency of PKL@AgNPs for MB and MO pollutants were 93.2% and 85.37% under UV and 75.18% and 70.03% under sun‐light irradiations, respectively. Furthermore, the PKL@AgNPs showed strong antibacterial and antifungal activities against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus mutans, Streptococcus mitis, Enterococcus faecalis, and Candida albicans with minimum inhibitory concentration (MIC) values of 0.58, 0.58, 0.58, 1.17, 2.34, 1.17, and 0.15 μg ml−1, respectively. The antioxidant activity of PKL@AgNPs was calculated and the results revealed that the percentage of DPPH inhibition increased (3.8% to 69.9%) with increasing the concentration of nanoparticles. Also, the PKL@AgNPs also revealed significant anticancer activity on k562 as a human leukemia cancer cell line (IC50 = 2.69 μg ml−1). All these investigations revealed that silver nanoparticles synthesized by natural extract have the potential to use as low‐cost and efficient nanoparticles for environmental and biomedical applications.

Study of Antibacterial and Anticancer Properties of bioAgNPs Synthesized Using Streptomyces sp. PBD-311B and the Application of bioAgNP-CNC/Alg as an Antibacterial Hydrogel Film against P. aeruginosa USM-AR2 and MRSA.

Here, we report the extracellular biosynthesis of silver nanoparticles (AgNPs) and determination of their antibacterial and anticancer properties. We also explore the efficacy of bioAgNPs incorporated in cellulose nanocrystals (CNCs) and alginate (Alg) for the formation of an antibacterial hydrogel film. Streptomyces sp. PBD-311B was used for the biosynthesis of AgNPs. The synthesized bioAgNPs were characterized using UV-Vis spectroscopy, TEM, XRD, and FTIR analysis. Then, the bioAgNPs’ antibacterial and anticancer properties were determined using TEMA and cytotoxicity analysis. To form the antibacterial hydrogel film, bioAgNPs were mixed with a CNC and Alg solution and further characterized using FTIR analysis and a disc diffusion test. The average size of the synthesized bioAgNPs is around 69 ± 2 nm with a spherical shape. XRD analysis confirmed the formation of silver nanocrystals. FTIR analysis showed the presence of protein capping at the bioAgNP surface and could be attributed to the extracellular protein binding to bioAgNPs. The MIC value of bioAgNPs against P. aeruginosa USM-AR2 and MRSA was 6.25 mg/mL and 3.13 mg/mL, respectively. In addition, the bioAgNPs displayed cytotoxicity effects against cancer cells (DBTRG-0.5MG and MCF-7) and showed minimal effects against normal cells (SVG-p12 and MCF-10A), conferring selective toxicity. Interestingly, the bioAgNPs still exhibited inhibition activity when incorporated into CNC/Alg, which implies that the hydrogel film has antibacterial properties. It was also found that bioAgNP-CNC/Alg displayed a minimal or slow release of bioAgNPs owing to the intermolecular interaction and the hydrogel’s properties. Overall, bioAgNP-CNC/Alg is a promising antibacterial hydrogel film that showed inhibition against the pathogenic bacteria P. aeruginosa and MRSA and its application can be further evaluated for the inhibition of cancer cells. It showed benefits for surgical resection of a tumor to avoid post-operative wound infection and tumor recurrence at the surgical site.

Novel static magnetic field effects on green chemistry biosynthesis of silver nanoparticles in Saccharomyces cerevisiae

The bacteriocidal properties of silver nanoparticles (AgNPs) depend on their average diameter (toxicity increases with decreasing diameter). In the present work, we describe novel green chemistry biosynthesis of AgNPs from AgNO3 added to cell-free culture medium of baker’s yeast, Saccharomyces cerevisiae, yielding nanoparticles in the range 11–25 nm. However, when yeast was grown in a moderate static magnetic field, AgNPs obtained from the resulting cell-free culture medium, were significantly smaller (2–12 nm) than those obtained without magnetic field. These latter nanoparticles were highly crystalline, stable and near-uniform shape. Furthermore, the antibacterial activity of AgNPs obtained from static magnetic fields were greater than those from control cultures. Static magnetic fields show a promising ability to generate biocidal nanoparticles via this novel green chemistry approach.

Ultrasound-assisted biosynthesis of Ag nanoparticles using Juglans negia L. leaves extract; Evaluation of total phenols, flavonoids, antioxidant potential and antibacterial activity

The present study aimed to synthesize silver nanoparticles (AgNPs) by using black walnut (Juglans negia L.) leaf extract from Iran through a rapidly and ecofriendly ultrasound-assisted method and stirring-assisted method. The synthesized AgNPs by two methods were characterized by different techniques such as Transmission Electron Microscopy (TEM), Scanning Electron Microscope (SEM), and UV–VIS Spectroscopy, FTIR, X-Ray Diffraction (XRD). The antimicrobial activities of both synthesized silver nanoparticles by two methods and also Juglans negia L. leaf extract were determined against four gram negative and two gram positive bacteria by well diffusion method and the Minimum Inhibitory Concentration test (MIC) and the results were comparable. The minimum inhibitory concentrations were achieved for biosynthesized AgNPs with assisted ultrasound method against two gram-negative bacteria E. coli and S. typhimurium (both 8 mg/mL). However, total phenols and flavonoids content of Juglans negia L. leaves extract were also determined. Additionally, the antioxidant activity was evaluated based on 2,2-diphenyl-1-picryl-hydrazyl (DPPH). Total phenols were 78.82±6.83 mg/g gallic acid equivalent, and total flavonoids were 446.23±2.32 mg/g rutin equivalent, and antioxidant capacity was 127.26±0.04 mg/g IC50.

Evaluation The Antibacterial Activity of Biosynthesis Silver Nanoparticles by Lactobacillus Gasseri Bacteria

Biosynthesis of AgNPs is a new approach in the field of nanotechnology with optimistic implementation in medicine, food control, and pharmacology. In this study, the silver nanoparticles were produced by Lactobacillus gasseri filtrate. The production of AgNPs was confirmed by the color change from yellow to brown. Using UV visible spectrophotometer at 424 nm wavelength, and X-ray diffraction, it was found that the size of the synthesized particles was 58.5 nm after applying Scherrer’s equation. The inhibitory activity of silver nitrate on the growth of some pathogenic isolates was studied Staphylococcus haemolyticus Gram positive, and Klebsiella pneumoniae Gram negative. The highest inhibitory diameter was 14.6 mm at 100% concentration (stock) against Staphylococcus haemolyticus bacteria was followed by that of Klebsiella pneumoniae bacteria with an average inhibition zone diameter reached 13.6 mm at 100% concentration. The highest effect was of AgNPs on the growth of Staphylococcus haemolyticus bacteria, as it found the average diameter of the inhibition zone reached to 29.3 mm, followed by Klebsiella pneumoniae with the average diameter of the inhibiting zone it was 22.6 mm at 100% concentration (stock). This study showed AgNPs have more antibacterial activity against Gram positive bacteria than Gram negative bacteria. The importance of this study lies in testing the effectiveness of by Lactobacillus gasseri bacteria in the biosynthesis of silver nanoparticles and studying their antibacterial activity on pathogenic bacteria.

In situ biosynthesized silver nanoparticle-incorporated synthesized zeolite A using Orthosiphon aristatus extract for in vitro antibacterial wound healing

The capability of synthesized zeolite A (SZ) to immobilize Ag ions (Ag-SZ) and Ag nanoparticles (AgNp-SZ) were comparatively studied. A novel approach of in situ biosynthesized AgNP-incorporated synthesized zeolite A (AgNp-SZ) was synthesized at an optimum volume of 0.4 mL of the Orthosiphon aristatus (O. aristatus) leaves plant extract (5%) using an in situ approach. In comparison, Ag-SZ was produced by loading the synthesized zeolite with Ag ions. All synthesized materials were characterized for their morphologies and physicochemical properties. The characterization analyses validate that the biosynthesized AgNP (<100 nm) using O. aristatus leaves extract was incorporated into the zeolite A. The antibacterial testing confirmed that these materials have antibacterial activity against Escherichia coli ATCC 11229 and Staphylococcus aureus ATCC 6538. MIC/MBC analysis demonstrated that in 0.9% saline solution, AgNP-SZ had higher antibacterial activity than Ag-SZ. The in vitro cell viability and migration assays were further examined towards human skin fibroblast cells HSF 1184. Results show that the materials are not cytotoxic to HSF 1184, and the biosynthesized AgNP-SZ promotes cell migration and proliferation higher than Ag-SZ. This research proved that the biocompatible antibacterial wound healing agent of AgNP-SZ can be synthesized using an in situ approach where the reduction process of Ag ions in the zeolite A can be performed using plant extract.

Antioxidant Properties and Potentiality of Silver Nanoparticles Biosynthesis of Thirty-Five Edible Bangladeshi Fruits

A comparison of total polyphenols (TP) and flavonoids (TF) contents, antioxidant activity, and silver nanoparticles (AgNPs) biosynthesis potentiality of 35 common edible fruits in Bangladesh were studied. Among the fruits, Emblica officinalis showed the highest content of TP (89 mg gallic acid equivalent (GAE)/g powder), reducing power (OD, 1.98 at 1 mg powder/ml), and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging activity (95.6% at 0.5 mg powder/ml) whereas the highest content (17.3 mg (+)-catechin equivalent (CE)/g powder) of TF was recorded in Garcinia cowa. The inhibitory concentration 50 (IC50) for DPPH-free radical scavenging of Annona reticulata, E. officinalis, G. cowa, Phoenix sylvestris, Psidium guajava and Syzygium cumini were 180, 21.8, 172, 188.9, 162.4 and 176.2 μg powder/ml, respectively. Litchi chinensis showed the highest total antioxidant capacity (79 mg GAE/g powder) followed by E. officinalis (69 mg GAE/g powder). The fruits showed a very strong correlation (r2 = 0.99) between TP and reducing power. P. guajava showed the highest potentiality (OD, 0.74 at 10 mg powder/ml) in the biosynthesis of AgNPs followed by S. cumini, A. reticulata and P. sylvestris. Therefore, most potential five fruits should be graded as E. officinalis &gt; S. cumini &gt; P. guajava &gt; A. reticulata &gt; P. sylvestris. Bangladesh J. Bot. 50(3): 445-451, 2021 (September)

Antimicrobial activity of silver nanoparticles against proteus mirabilis isolated from patients with food diabetes ulcer

The aim of this study was to study the antibacterial activity of Silver nanoparticles synthesized by L. acidophilus and the biosynthesis of AgNPs from nonpathogenic bacterial isolates. Fifty samples were obtained during the period from December 2020 to March 2021. AgNO3 was used as a precursor for the synthesis of AgNPs. Biological AgNPs were originally shown by change the color, yellow to reddish-brown. The categorization of AgNPs accomplished by SEM, XRD, AFM, and EDS. SEM exhibited well-dispersed AgNPs, homogenous with a diameter of 40-60 nm, with inconstant shapes, mostly spherical form. XRD detected that the size of AgNPs was 34 nm. AFM also showed the three-dimensional structure of AgNPs and their diameter which was 45.82 nm. EDS exhibited that the AgNPs fabricated was 94.82% silver and 5.18 % oxygen. Silver nanoparticles displayed antibacterial action to MDR of P. mirabilis.

Characterization and bioactivities of silver nanoparticles green synthesized from Vietnamese Ganoderma lucidum

In this study, the utilization of Vietnamese Ganoderma lucidum (G. lucidum) extract was scrutinized under different operational conditions including reaction time, AgNO3:extract mass ratio, and reaction temperature to establish a rapid, cost–effective, and eco–friendly method with a high yield rate and nanoparticle stabilization. The characterization showed that the as–synthesized silver nanoparticles (AgNPs) were well–crystalline with an average size of 11.38 ± 5.51 nm. Meanwhile, the Fourier–transform infrared spectrometry of AgNPs and extract samples showed the absorption bands including –OH stretching, symmetric aliphatic bending, and C–OH stretching vibrations belonging to the presence of polyphenols, triterpenoids, and polysaccharides, respectively. These bands reveal an astounding decline in the polyphenol, triterpenoid, and flavonoid content of the crude G. lucidum extracts, which is consistent with the results obtained from colorimetric methods. In liquid chromatography–mass spectrometry of AgNPs and extract samples, various peaks were detected and they shared significant differences in intensity after the reaction. As a result, the phytochemicals from G. lucidum extracts were confirmed to play the role of reducing silver ions to AgNPs and act as a capping agent to stabilize the colloid mixture. In the biological tests, the colloidal AgNPs demonstrated an extraordinary antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans, with IC50 values of 17.97, 17.06, 1.32, 54.69, and 27.78 µg/mL, respectively. The antioxidant capacity of AgNPs was evaluated using 2,2–diphenyl–1–picrylhydrazyl free radical reagent (IC50 = 447.120 ± 0.084 µg/mL). In addition, the colloidal AgNPs possessed better anticancer activity against the human epidermic carcinoma cancer cell line (KB) with IC50 values of 190.06 ± 3.62 µg/mL when compared to the crude extract. The results of the bioactivity evaluations exhibited the potential utilization of G. lucidum extract as a natural source for the colloidal AgNPs biosynthesis and their application in various areas, particularly as an antimicrobial agent in food, pharmaceutical, and cosmetic product preservation to combat bacterial infection.

English

Spillage of protoscoleces within hydatid fluid during surgery for hydatid cyst is the main reason for its recurrence. Therefore, to inactivate the protoscoleces, various scolicidal substances have been tested. However, novel and more efficient agents are needed owing to several associated complications. This study focused on the effects of green synthetic Silver Nanoparticles (AgNPs) from Zizyphus spina- christi leaves on Echinococcus granulosus protoscoleces. Also, to evaluate the blood compatibility of Ag NPs. The Ag NPs were identified by ultraviolet-visible (UV-Visible) spectrophotometer, X-ray diffraction (XRD), Scanning electron microscopy imaging, and Energy-dispersive X-ray spectroscopy (EDX). Hydatid fluid was aspirated aseptically from cysts of infected sheep liver. The protoscoleces were exposed to Ag NPs at several concentrations. Also, scanning electron microscopy for ultrastructural changes and in vitro erythrocytes lysis was performed. The Ag NPs were spherical; the particles' size reached 50 nm, and presented a surface plasmon peak around 460 nm. The current study's findings indicated the powerful in vitro scolicidal efficacy of the green biosynthesized AgNPs. Several morphological alterations were observed on the protoscoleces by optical and scanning electron microscopy. Lysis of RBCs at different doses of Ag NPs was significantly (P≤0.05) less than the positive control value, thus proposing its biocompatibility. This work suggests that chemicals like polyphenols present in the extract of Z. spina- christi act as reducing and stabilizers agents to create Ag NPs Nevertheless, further investigations are needed to investigate the Ag NPs scolicidial effects in animal models.

O-004. Circulating SIGLEC6 is deranged in preeclampsia and may be a biomarker of disease severity

In this study, the utilization of Vietnamese Ganoderma lucidum (G. lucidum) extract was scrutinized under different operational conditions including reaction time, AgNO3:extract mass ratio, and reaction temperature to establish a rapid, cost–effective, and eco–friendly method with a high yield rate and nanoparticle stabilization. The characterization showed that the as–synthesized silver nanoparticles (AgNPs) were well–crystalline with an average size of 11.38 ± 5.51 nm. Meanwhile, the Fourier–transform infrared spectrometry of AgNPs and extract samples showed the absorption bands including –OH stretching, symmetric aliphatic bending, and C–OH stretching vibrations belonging to the presence of polyphenols, triterpenoids, and polysaccharides, respectively. These bands reveal an astounding decline in the polyphenol, triterpenoid, and flavonoid content of the crude G. lucidum extracts, which is consistent with the results obtained from colorimetric methods. In liquid chromatography–mass spectrometry of AgNPs and extract samples, various peaks were detected and they shared significant differences in intensity after the reaction. As a result, the phytochemicals from G. lucidum extracts were confirmed to play the role of reducing silver ions to AgNPs and act as a capping agent to stabilize the colloid mixture. In the biological tests, the colloidal AgNPs demonstrated an extraordinary antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans, with IC50 values of 17.97, 17.06, 1.32, 54.69, and 27.78 µg/mL, respectively. The antioxidant capacity of AgNPs was evaluated using 2,2–diphenyl–1–picrylhydrazyl free radical reagent (IC50 = 447.120 ± 0.084 µg/mL). In addition, the colloidal AgNPs possessed better anticancer activity against the human epidermic carcinoma cancer cell line (KB) with IC50 values of 190.06 ± 3.62 µg/mL when compared to the crude extract. The results of the bioactivity evaluations exhibited the potential utilization of G. lucidum extract as a natural source for the colloidal AgNPs biosynthesis and their application in various areas, particularly as an antimicrobial agent in food, pharmaceutical, and cosmetic product preservation to combat bacterial infection.

Synthesis of Silver Nanoparticles Using L.Rosa Flowers Extracts: Thermodynamic and Kinetic Studies on the Inhibitoty Effects of Nanoparticles on Creatine Kinase Activity

The present work investigates the synthesis of silver nanoparticles (AgNPs) by a biological method using L.Rosa flower extract and silver nitrate as precursors. Optimum conditions of synthesis were studies, such as pH, temperature, concentration of extract, concentration of silver nitrate, and stability with time. Characterization of AgNPs was carried out using UV-visible Spectroscopy, Scanning Electron Microscopy, X-Ray Diffraction, Fourier Transform Infrared and Transmission Electron Microscopy. The biosynthesized AgNPs exhibited inhibitory effects on creatine kinase activity in the sera of patients with myocardial infarction, compared with control subjects. Thermodynamic and kinetic studies of creatine kinase were performed. Further studies on other biological activities were performed to exploit AgNPs full potential. In conclusions, the present study utilize a simple, cheap and environmentally green method to synthesize silver nanoparticles. This single step procedure is more suitable for large scale production as it is rapid and eliminates the elaborate processes employed in the other bio-based protocols (e.g. by using fungi and bacteria).

Antibacterial Applications of Biosynthesized AgNPs: A Short Review (2015-2020)

Bacterial resistance to a wide spectrum of antimicrobial medicines has evolved as a major public health concern. Antibiotics are medications that are used to kill microorganisms that could cause serious illness or death. Nanotechnology has exploded as a significant and appealing field of research, with innovative features and functionalities in a variety of fields. Silver is a versatile antibacterial and anticancer medicinal agent in the form of nanoparticles. Silver Nanoparticles (AgNPs) have been implicated in a wide variety of medicinal benefits. This review article addresses antibacterial applications of biosynthesized AgNPsthat have been researched over the last decade. AgNPs' antimicrobial potential against a variety of bacterial agents is discussed.

Spectral and structure characterization of Ferula assafoetida fabricated silver nanoparticles and evaluation of its cytotoxic, and photocatalytic competence

This study aims to develop an eco-friendly method for rapidly synthesizing silver nanoparticles (AgNPs) using Asafoetida ethanol extracts and to validate AgNPs synthesis using UV–vis spectroscopy (absorption spectrum), FTIR (functional groups), XRD (crystallinity), FE-SEM (size of the particles) and SEM-EDAX (Purity). Furthermore, to evaluate the anti-proliferative effect of Ag NPs against grown cultured L6 cell lines, studies have shown that AgNPs biosynthesis inhibits cancer cell growth compared to control cell lines. UV–vis absorption verified the existence of Ag NPs, and the spectrum was observed at 480 nm. Functional groups are present in the synthesized Ag NPs were shifted on 528.48 cm−1 confirmed using an FT-IR spectrum. Consequently, anti-cancer efficacy observed the IC50 value of As Ag NPs against L6 cells was 1.0 μg/mL for 48 h. Finally, using a halogen lamp, studies explored the photocatalytic degradation of AgNPs against the methylene blue radioactive dye and achieved a 96 percent degradation rate in 90 min. Asafoetida mediated silver nanoparticles show grater photodegradation for methylene blue dye, which is present in textile industries, when exposed to solar light, and it has a wide range of potential applications in wastewater treatment. As a whole, biosynthesized silver nanoparticles showed excellent cytotoxic, antioxidant, and photocatalytic dye degradation effects.

Biosynthesis of Silver Nanoparticles Using Orange Peel Extract for Application in Catalytic Degradation of Methylene Blue Dye

Interest in the biosynthesis of silver nanoparticles (AgNPs) has been steadily increasing primarily due to their numerous applications in various fields, low-cost, use of non-toxic environmentally-friendly materials and easy implementation. This study focused on the biosynthesis of AgNPs using orange peel extract (OPE), optimization of process conditions, and application in catalytic degradation of methylene blue (MB) dye used in the textile industry. A central composite design in response surface methodology resulted in optimum conditions of 0.0075 g dry peel/mL for OPE concentration, pH of 11 and 1.5 mM silver nitrate concentration. The optimum conditions for the response variables corresponded to the peak absorbance of 0.79 and SPR wavelength of 403.8 nm in UV-vis spectra, and minimum particle size of 12.9 nm. In addition, peak absorbance and SPR wavelength appeared to be related to the size of the AgNPs. A full-factorial design for the catalytic degradation of MB dye by the biosynthesized AgNPs for 1 h indicated the maximum influence of AgNPs compared to the concentrations of MB dye and NaBH4 in decreasing order. The MB dye was reduced rapidly with NaBH4 in the presence of AgNPs due to their catalytic action. The findings of the study show the potential of OPE for the biosynthesis of AgNPs with excellent catalytic activity for the treatment of MB dye in industrial effluent.

Investigation of the Oxidative Stress Response of a Green Synthesis Nanoparticle (RP-Ag/ACNPs) in Zebrafish.

Silver nanoparticles (AgNPs) are prominent nanomaterials that are efficiently used in different industries including medical products, water treatment, and cosmetics. However, AgNPs are known to cause adverse effects on the ecosystem and human health. In this study, aqueous extract of Rumex patientia (RP) was used as a reducing and stabilizing agent in AgNP biosynthesis. The obtained activated carbon (AC) from Chenopodium album (CA) plant was combined with RP-AgNPs to synthesize RP-Ag/AC NPs. Next, the effects of these green synthesis RP-Ag/AC NPs on zebrafish (Danio rerio) embryos and larvae were investigated. First, we characterized the RP-Ag/AC NPs by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) and determined LC50 value as 217.23mg/L at 96h. Next, the alterations in survival rate, hatching rate, and morphology of the larvae at 96h were monitored. The survival rates decreased in a dose-dependent manner. Morphological defects such as yolk sac edema, pericardial edema, spinal curvature, and tail malformation in the NP-treated larvae were observed. RP-Ag/AC NPs stimulated the production of neuronal NOS (nNOS) and 8-OHdG in zebrafish brain tissues in a dose-dependent manner and enhanced neutrophil degeneration and necrosis at concentrations of 50 and 100mg/L. Thus, the obtained data suggest that the green synthesis process is not sufficient to reduce the effect of oxidative stress caused by AgNPs on oxidative signaling.

Silver Nanoparticles Biosynthesis, Characterization, Antimicrobial Activities, Applications, Cytotoxicity and Safety Issues: An Updated Review.

Rapid advances in nanotechnology have led to its emergence as a tool for the development of green synthesized noble metal nanoparticles, especially silver nanoparticles (AgNPs), for applications in diverse fields such as human health, the environment and industry. The importance of AgNPs is because of their unique physicochemical and antimicrobial properties, with a myriad of activities that are applicable in various fields, including the pharmaceutical industry. Countries with high biodiversity require the collection and transformation of information about biological assets into processes, associations, methods and tools that must be combined with the sustainable utilization of biological diversity. Therefore, this review paper discusses the applicable studies of the biosynthesis of AgNPs and their antimicrobial activities towards microorganisms in different areas viz. medicine and agriculture. The confirmed antiviral properties of AgNPs promote their applicability for SARS-CoV-2 treatment, based on assimilating the virus’ activities with those of similar viruses via in vivo studies. In this review, an insight into the cytotoxicity and safety issues of AgNPs, along with their future prospects, is also provided.

Biosynthesis of Silver Nanoparticles Using Juglans Regia Green Husk (Walnut) Water Extract and evaluation Antibacterial activity

Biosynthesis of Ag-NPs at room temperature by using Juglans regia (J. regia) green husk extract which acts as reductant and stabilizer, simultaneously. The Ag/J. regia were characterized by using UV–visible, zeta potential, TEM, and AFM. Formation of Ag/ J. regia was determined by UV–vis spectroscopy, where absorption maxima surface plasmon at 400-460 nm. The zeta potential analysis indicated that J. regia green husk extract was negative and increasing in Ag/ J. regia. TEM images show the mean particle size was 31.37 nm with the standard deviation of 7.1 nm, where confirm by AFM measurements. The XRD study indicates the crystalline nature of the Ag-NPs. The antibacterial activity of Ag-NPs was investigated against Gram-positive and Gram-negative bacteria by the disc diffusion method were found to have high antibacterial activity. These results show that Ag-NPs can be useful in different biologic research and biomedical applications.

Synthesis of silver nanoparticles using living electroactive biofilm protected by polydopamine

SummaryThe biosynthesis of metal nanoparticles from precious metals has been of wide concern. Their antibacterial activity is a main bottleneck restricting the bacterial activity and reduction performance. Here, bio-electrochemical systems were used to harvest electroactive biofilms (EABs), where bacteria were naturally protected by extracellular polymeric substances to keep activity. The biofilm was further encapsulated with polydopamine (PDA) as additional shield. Silver nanoparticles (AgNPs) were biosynthesized on EABs, whose electroactivity could be fully recovered after Ag+ reduction. The PDA increased bacterial viability by 90%–105%, confirmed as an effective protection against antibacterial activity of Ag+/AgNPs. The biosynthetic process changed the component and function of the microbial community, shifting from bacterial Fe reduction to archaeal methanogenesis. These results demonstrated that the electrochemical acclimation of EABs and encapsulation with PDA were effective protective measures during the biosynthesis of AgNPs. These approaches have a bright future in the green synthesis of nanomaterials, biotoxic wastewater treatment, and sustainable bio-catalysis.