Production Of AgNPs Research Articles

Green Synthesis of Silver Nanoparticles Using Aqueous Citrus limon Zest Extract: Characterization and Evaluation of Their Antioxidant and Antimicrobial Properties.

The current work concentrated on the green synthesis of silver nanoparticles (AgNPs) through the use of aqueous Citrus limon zest extract, optimizing the different experimental factors required for the formation and stability of AgNPs. The preparation of nanoparticles was confirmed by the observation of the color change of the mixture of silver nitrate, after the addition of the plant extract, from yellow to a reddish-brown colloidal suspension and was established by detecting the surface plasmon resonance band at 535.5 nm, utilizing UV-Visible analysis. The optimum conditions were found to be 1 mM of silver nitrate concentration, a 1:9 ratio extract of the mixture, and a 4 h incubation period. Fourier transform infrared spectroscopy spectrum indicated that the phytochemicals compounds present in Citrus limon zest extract had a fundamental effect on the production of AgNPs as a bio-reducing agent. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential (ZP), dynamic light scattering (DLS), SEM, EDX, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis, which showed crystalline spherical silver nanoparticles. In addition, the antimicrobial and antioxidant properties of this bioactive silver nanoparticle were also investigated. The AgNPs showed excellent antibacterial activity against one Gram-negative pathogens bacteria, Escherichia coli, and one Gram-positive bacteria, Staphylococcus aureus, as well as antifungal activity against Candida albicans. The obtained results indicate that the antioxidant activity of this nanoparticle is significant. This bioactive silver nanoparticle can be used in biomedical and pharmacological fields.

Biological Synthesis of Low Cytotoxicity Silver Nanoparticles (AgNPs) by the Fungus Chaetomium thermophilum-Sustainable Nanotechnology.

Fungal biotechnology research has rapidly increased as a result of the growing awareness of sustainable development and the pressing need to explore eco-friendly options. In the nanotechnology field, silver nanoparticles (AgNPs) are currently being studied for application in cancer therapy, tumour detection, drug delivery, and elsewhere. Therefore, synthesising nanoparticles (NPs) with low toxicity has become essential in the biomedical area. The fungus Chaetomium thermophilum (C. thermophilum) was here investigated—to the best of our knowledge, for the first time—for application in the production of AgNPs. Transmission electronic microscopy (TEM) images demonstrated a spherical AgNP shape, with an average size of 8.93 nm. Energy-dispersive X-ray spectrometry (EDX) confirmed the presence of elemental silver. A neutral red uptake (NRU) test evaluated the cytotoxicity of the AgNPs at different inhibitory concentrations (ICs). A half-maximal concentration (IC50 = 119.69 µg/mL) was used to predict a half-maximal lethal dose (LD50 = 624.31 mg/kg), indicating a Global Harmonized System of Classification and Labelling of Chemicals (GHS) acute toxicity estimate (ATE) classification category of 4. The fungus extract showed a non-toxic profile at the IC tested. Additionally, the interaction between the AgNPs and the Balb/c 3T3 NIH cells at an ultrastructural level resulted in preserved cells structures at non-toxic concentrations (IC20 = 91.77 µg/mL), demonstrating their potential as sustainable substitutes for physical and chemically made AgNPs. Nonetheless, at the IC50, the cytoplasm of the cells was damaged and mitochondrial morphological alteration was evident. This fact highlights the fact that dose-dependent phenomena are involved, as well as emphasising the importance of investigating NPs’ effects on mitochondria, as disruption to this organelle can impact health.

Non-Thermal Plasma Reduction of Ag+ Ions into Silver Nanoparticles in Open Atmosphere under Statistically Optimized Conditions for Biological and Photocatalytic Applications.

An environmentally friendly non-thermal DC plasma reduction route was adopted to reduce Ag+ ions at the plasma–liquid interface into silver nanoparticles (AgNPs) under statistically optimized conditions for biological and photocatalytic applications. The efficiency and reactivity of AgNPs were improved by statistically optimizing the reaction parameters with a Box–Behnken Design (BBD). The size of the AgNPs was chosen as a statistical response parameter, while the concentration of the stabilizer, the concentration of the silver salt, and the plasma reaction time were chosen as independent factors. The optimized parameters for the plasma production of AgNPs were estimated using a response surface methodology and a significant model p < 0.05. The AgNPs, prepared under optimized conditions, were characterized and then tested for their antibacterial, antioxidant, and photocatalytic potentials. The optimal conditions for these three activities were 3 mM of stabilizing agent, 5 mM of AgNO3, and 30 min of reaction time. Having particles size of 19 to 37 nm under optimized conditions, the AgNPs revealed a 82.3% degradation of methyl orange dye under UV light irradiation. The antibacterial response of the optimized AgNPs against S. aureus and E. coli strains revealed inhabitation zones of 15 mm and 12 mm, respectively, which demonstrate an antioxidant activity of 81.2%.

Physiological Response of Saccharomyces cerevisiae to Silver Stress.

Silver nanoparticle (AgNP) production and their use as antimicrobial agents is a current area of active research. Biosynthesis is the most sustainable production method, and fungi have become candidates of interest in AgNP production. However, investigations into the physiological responses of fungi due to silver exposure are scanty. This present work utilized two strains of Saccharomyces cerevisiae (one used in commercial fermentation and a naturally occurring strain) to determine the physiological consequences of their transient exposure to AgNO3. The assessments were based on studies involving growth curves, minimal inhibitory concentration assays, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging, and inductively coupled plasma optical emission spectroscopy (ICP-OES). Results indicated (a) the capability of S. cerevisiae to produce silver nanoparticles, even at elevated levels of exposure; (b) strain origin had no significant impact on S. cerevisiae physiological response to AgNO3; and (c) coexposure to copper and silver significantly increased intracellular copper, silver, and calcium in treated yeast cells. In addition, electron microscopy and ICP-OES results revealed that both strains internalized silver after exposure, resulting in the shrunken and distorted physical appearance visible on SEM micrographs of treated cells. Though a promising candidate for AgNPs biosynthesis, this study analyzed the effects of transient silver exposure on S. cerevisiae growth physiology and morphology.

Biological Synthesis and Characterization of Silver Nanoparticles by Orthosyphan Rubicundas

There are many metal nanoparticles, usually formed in the range of 1 to 100 nm size. Silver nanoparticles (AgNPs) have the unique properties of silver ions and hence are useful in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The use of plants in the production of AgNPs has drawn attention due to their rapid, eco-friendly, non-pathogenic, economical protocol, and a single-step technique for the biosynthetic processes. Though till date, many researchers have explored biosynthesis of nanoparticles using different species belonging to Lamiaceae. Orthosyphan rubicundas is the plant chosen from this family for the study as it is wildly grown in the as a weed and rarely studied in the nanoparticle synthesis.The silver-based compounds were used as known as non-toxic inorganic antibacterial agents expressing their biocidal properties in many application. For characterization of AgNPs, the physicochemical properties of nanoparticles were studied, which explained the detailed result of their behaviour, efficacy, safety, and biodistribution. Characterization is performed using a variety of analytical techniques, mainly including X-ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM).

Green Synthesis and Antibacterial Activities of Silver Nano particles Mediated by Extract of Cucurbita maxima (Pumpkin) Fruit Pith

Synthesis of silver nanoparticles (AgNPs) has become a necessary field of applied science. Biological method for synthesis of AgNPs by cucurbita maxima fruit pith extracts was used. The AgNPs were identified by UV–visible spectrometry; X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). The presence of surface plasmon band around 420 nm indicates AgNPs formation. Parameter optimization showed the smallest size of AgNPs (2.86 ± 0.3 nm) was obtained with 0.1 M AgNO3 at 40oC. The present study provides the proof that the molecules within aqueous cucurbita maxima fruit pith extracts facilitate synthesis of AgNPs and highlight on value-added from cucurbita maxima fruit pith and fruit peel extracts for cost effectiveness. Also, eco-friendly medical and nanotechnologybased industries could also be provided. Size of prepared AgNPs could be controlled by temperature and AgNO3 concentration. Further studies are required to study effect of more parameters on size and morphology of AgNPs as this will help in the control of large scale production of biogenic AgNPs. The synthesized silver nanoparticles are screened antibacterial activities

Poly(N-isopropylacrylamide)-interpenetrated chitosan coils working as nanoreactors for controlled silver nanoparticle growth

A new precursor (Ag+/CS/PNIPA) arranged as a nanogel (nanoreactor) is obtained from the aqueous mixture of Ag+, chitosan (CS) and poly(N-isopropylacrylamide) (PNIPA). A model synthetic system based on the thermally induced aqueous silver ions-CS reaction to form silver nanoparticles (AgNP) is used as a starting point to assess the PNIPA role as a thermo-sensitive additive of synthesis in a low content for the production of size-controlled AgNP. As expected, the PNIPA phase transition produced by the temperature increase leads to chitosan nanogel contraction, lowering the diffusion of ionic species. PNIPA behaves as a successful additive between 5.6 and 10.5 wt% of content blended with chitosan, noticeably improving AgNP nucleation during thermal treatment at 90 °C. Higher PNIPA contents are less effective in achieving size control and broader size distributions are generated. The PNIPA effect on the nanoreactor structure is characterized by rheology, modelled and analyzed against the AgNP morphology obtained.

In Vivo and In Vitro Antimicrobial Activity of Biogenic Silver Nanoparticles against Staphylococcus aureus Clinical Isolates.

Staphylococcus aureus can cause a wide range of severe infections owing to its multiple virulence factors in addition to its resistance to multiple antimicrobials; therefore, novel antimicrobials are needed. Herein, we used Gardenia thailandica leaf extract (GTLE), for the first time for the biogenic synthesis of silver nanoparticles (AgNPs). The active constituents of GTLE were identified by HPLC, including chlorogenic acid (1441.03 μg/g) from phenolic acids, and quercetin-3-rutinoside (2477.37 μg/g) and apigenin-7-glucoside (605.60 μg/g) from flavonoids. In addition, the antioxidant activity of GTLE was evaluated. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, transmission and scanning electron microscopy (SEM), zeta potential, dynamic light scattering, and X-ray diffraction. The formed AgNPs had a spherical shape with a particle size range of 11.02–17.92 nm. The antimicrobial activity of AgNPs was investigated in vitro and in vivo against S. aureus clinical isolates. The minimum inhibitory concentration (MIC) of AgNPs ranged from 4 to 64 µg/mL. AgNPs significantly decreased the membrane integrity of 45.8% of the isolates and reduced the membrane potential by flow cytometry. AgNPs resulted in morphological changes observed by SEM. Furthermore, qRT-PCR was utilized to examine the effect of AgNPs on the gene expression of the efflux pump genes norA, norB, and norC. The in vivo examination was performed on wounds infected with S. aureus bacteria in rats. AgNPs resulted in epidermis regeneration and reduction in the infiltration of inflammatory cells. Thus, GTLE could be a vital source for the production of AgNPs, which exhibited promising in vivo and in vitro antibacterial activity against S. aureus bacteria.

Trichogenic Silver-Based Nanoparticles for Suppression of Fungi Involved in Damping-Off of Cotton Seedlings.

Mycogenic silver nanoparticles (AgNPs) produced by some biocontrol agents have shown the ability to inhibit the growth of numerous plant pathogenic fungi, which may be a unique method of disease management. This study describes the extracellular production of AgNPs by Trichoderma harzianum. The size, shape, charge, and composition of the AgNPs were subsequently studied by UV-visible spectroscopy, DLS, zeta potential, TEM, SEM, and EDX, among other methods. The AgNPs had sizes ranging from 6 to 15 nm. The antifungal activities of bio-synthesized AgNPs and two commercial fungicides (Moncut and Maxim XL) were tested against three soil-borne diseases (Fusarium fujikuroi, Rhizoctonia solani, and Macrophomina phaseolina). Cotton seedling illnesses were significantly reduced under greenhouse settings after significant in vitro antifungal activity was documented for the control of plant pathogenic fungi. The use of biocontrol agents such as T. harzianum, for example, may be a safe strategy for synthesizing AgNPs and using them to combat fungus in Egyptian cotton.

Pseudomonas indica-Mediated Silver Nanoparticles: Antifungal and Antioxidant Biogenic Tool for Suppressing Mucormycosis Fungi.

Mucormycosis is considered one of the most dangerous invasive fungal diseases. In this study, a facile, green and eco-friendly method was used to biosynthesize silver nanoparticles (AgNPs) using Pseudomonas indica S. Azhar, to combat fungi causing mucormycosis. The biosynthesis of AgNPs was validated by a progressive shift in the color of P. indica filtrate from colorless to brown, as well as the identification of a distinctive absorption peak at 420 nm using UV-vis spectroscopy. Fourier-transform infrared spectroscopy (FTIR) results indicated the existence of bioactive chemicals that are responsible for AgNP production. AgNPs with particle sizes ranging from 2.4 to 53.5 nm were discovered using transmission electron microscopy (TEM). Pattern peaks corresponding to the 111, 200, 220, 311, and 222 planes, which corresponded to face-centered cubic forms of metallic silver, were also discovered using X-ray diffraction (XRD). Moreover, antifungal activity measurements of biosynthesized AgNPs against Rhizopus Microsporus, Mucor racemosus, and Syncephalastrum racemosum were carried out. Results of antifungal activity analysis revealed that the biosynthesized AgNPs exhibited outstanding antifungal activity against all tested fungi at a concentration of 400 µg/mL, where minimum inhibitory concentrations (MIC) were 50, 50, and 100 µg/mL toward R. microsporus, S. racemosum, and M. racemosus respectively. In addition, the biosynthesized AgNPs revealed antioxidant activity, where IC50 was 31 µg/mL when compared to ascorbic acid (0.79 µg/mL). Furthermore, the biosynthesized AgNPs showed no cytotoxicity on the Vero normal cell line. In conclusion, the biosynthesized AgNPs in this study can be used as effective antifungals with safe use, particularly for fungi causing mucormycosis.

Silver Nanoparticle Production by the Cyanobacterium Cyanothece sp.: De Novo Manipulation of Nano-Biosynthesis by Phytohormones.

Background: Numerous cyanobacteria have the potential to reduce metallic ions to form pure metal nanoparticles in a green biosynthesis process. Aim: To investigate the production capacity of silver nanoparticles by the cyanobacterium Cyanothece sp. and to examine the effect of five different phytohormones, indole acetic acid, kinetin; gibberellic acid; abscisic acid; and methyl jasmonate, on this capacity. Methods: The cyanobacterial strain was grown for 60 days and the harvested cyanobacterium biomass was incubated with 0.1 mM of AgNO3. Percentage conversion of Ag+ to Ag0 was calculated to indicate the AgNPs’ production capacity. Different concentrations of the five phytohormones were added to cultures and the AgNP production was monitored throughout different time intervals. Results: Cyanothece sp. biosynthesized spherical AgNPs (diameter range 70 to 140 nm, average diameter 84.37 nm). The addition of indole acetic acid and kinetin provoked the maximum conversion (87.29% and 55.16%, respectively) of Ag+ to Ag0, exceeding or slightly below that of the control (56%). Gibberellic and abscisic acids failed to elevate the Ag+ to Ag0 conversion rate (45.23% and 47.95%, respectively) above that of the control. Methyl jasmonate increased the Ag+ to Ag0 conversion rate to 90.29%, although nearly all the cyanobacterial cultures died at the end. Conclusion: Phytohormones could be used to induce or inhibit the green production of AgNPs with the cyanobacterium Cyanothece sp. This novel manipulation technique may have several applications in agriculture or biomedicine.

Evaluation of the inhibitory impact of biosynthesized silver nanoparticles using Bacillus cereus and Chromobacterium violaceum bacteria on some intestinal protozoa.

Nano materials are utilized to improve the performance of some pharmaceuticals and materials, as well as to lessen the collateral damage they cause. The purpose of this study was to look at the effect of silver nanoparticles (AgNPs) produced by bacteria on some trophozoites of intestinal parasites. The silver nanoparticles were synthesized using Bacillus cereus (BAgNPs) and Chromobacterium violaceum (ChAgNPs) bacteria. The AgNPs production was confirmed by several tests and techniques, such as electron microscopy. The results of the analysis showed that the size of these particles was within the range of 21-96.71 nm for both BAgNPs and ChAgNPs. In vitro and in vivo efficacy were tested on some trophozoites of intestinal parasites. The effect of the AgNPs on Entamoeba histolytica trophozoites in culture was significantly higher compared to metronidazole. The highest percentage of inhibition was 70.6% and 76.5% for the particles prepared from B. cereus and C. violaceum without significant differences between the two bacteria, compared to 57.6% inhibition for metronidazole. The in vivo effect of the AgNPs on Giardia lamblia exceeded that of metronidazole and led to the total disappearance of the stages from mice faeces after 3-4 days. Likewise, Tritrichomonas muris numbers were also reduced in infected mice treated with AgNPs, with the highest inhibition rate of 81.3%. From above can concluded these bacterially produced nanoparticles have proven strong efficacy, and it is possible to recommend their use independently after conducting studies on the extent of their effects on the body and proving their safety.

Synthesis of silver nanoparticles using Lactobacillus bulgaricus and assessment of their antibacterial potential.

Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.

Phenolic Content, Antioxidant, Antibacterial, and Anti-Acetylcholinesterase Activities of Biosynthesized and Characterized Silver Nanoparticles from Tunisian Medicinal Lichen Species.

Lichens produce a myriad of bioactive compounds that can be exploited as reducing and capping agents in the green process of synthesizing nanoparticles. In this study, we exploit a simple, environmentally safe method for synthesizing silver nanoparticles (AgNPs), using aqueous extracts of three lichen species (Lobaria pulmonaria, Ramalina farinacea, and Evernia prunastri) for the first time. Characterization showed that the three lichen species selected could be perfectly suitable as reducing agents to produce AgNPs. First, ultraviolet-visible spectroscopy confirmed the presence of metallic silver with a maximum absorbance at 425 nm. Second, Fourier transform infrared spectroscopy analysis confirmed the chemical compounds involved in reduction. Third, the elemental composition of AgNPs was illustrated by energy dispersive X-ray spectroscopy. Finally, scanning electron microscopy images displayed the size and shape of biosynthesized particles. The prepared extracts containing AgNPs showed high contents of phenolic compounds and high antioxidant activities on three assays (DPPH, ferric reducing power, and chelating power). Moreover, since bacteria are developing resistance to many common antibiotics, AgNPs produced in an environmentally safe method are an interesting replacement. The antibacterial assessment revealed more effective activity against Gram-negative than Gram-positive bacteria and a bactericidal effect against all strains tested. In this study, we present a pioneering evaluation of acetylcholinesterase inhibition by lichen-based AgNPs. The three extracts exhibited strong enzyme inhibition, with IC50 values of 3.46 ± 0.09, 3.59 ± 0.02, and 4.34 ± 0.03 mg/mL for L. pulmonaria, R. farinacea, and E. prunastri, respectively. The green approach presented would encourage the nontoxic production of AgNPs, suggesting pharmaceutical applications.

Biological Synthesis of Silver Nanoparticles and their Biomedical Activity: A Review

Nanotechnology studies the various phenomena of physio-chemical procedures and biological properties for the generation of nanosized particles, and their rising challenges in the various sectors, like medicine, engineering, agriculture, electronic, and environmental studies. The nanosized particles exhibit good anti-microbial, anti-inflammatory, cytotoxic, drug delivery, anti-parasitic, anti-coagulant and catalytic properties because of their unique dimensions with large surface area, chemical stability and higher binding density for the accumulation of various bio-constituents on their surfaces. Biological approaches for the synthesis of silver nanoparticles (AgNPs) have been reviewed because it is an easy and single-step protocol and a viable substitute for the synthetic chemical-based procedures. Physical and chemical approaches for the production of AgNPs are also mentioned herein. Biological synthesis has drawn attention because it is cost-effective, faster, non-pathogenic, environment-friendly, easy to scale-up for large-scale synthesis, and having no demand for usage of high pressure, energy, temperature, or noxious chemical ingredients, and safe for human therapeutic use. Therefore, the collaboration of nanomaterials with bio-green approaches could extend the utilization of biological and cytological properties compatible with AgNPs. In this perspective, there is an immediate need to develop ecofriendly and biocompatible techniques, which strengthen efficacy against microbes and minimize toxicity for human cells. The present study introduces the biological synthesis of silver nanoparticles, and their potential biomedical applications have also been reviewed.

Mycogenic fabrication of silver nanoparticles using Picoa, Pezizales, characterization and their antifungal activity

In this work, silver nanoparticles have been mycofabricated from Picoa sp. (a desert truffle) for the first time. Also, the antifungal activity of Picoa-AgNPs has been investigated against three pathogenic fungi, including Pythium sp., Aspergillus flavus, and Aspergillus niger, which can cause severe damage to health and agriculture. Morphology and physico-chemical characteristics of the mycofabricated AgNPs were thoroughly described by UV–VIS, XRD, FESEM, TEM, FT-IR and Zeta Potential analyses. The optimum synthesis time of the AgNPs during the reaction progress was 60 min and outstanding at the peak of 440 nm. Nano-irregular shapes with an average size of 19.5 nm and high stability (−20.9 mV) have been recorded. FT-IR spectra showed high amino acid content in the Picoa sp. extract efficiently will achieves the bioreduction reaction of Ag ions to Ag atoms. The higher inhibition percentage of Picoa-AgNPs was 30.81% against Pythium sp. at the concentration of 10%, while the concentration of 5% showed a low inhibitory effect (13.51%). The concentration of 5% exhibited an inhibitory impact reached 16.67% against Aspergillus niger. These findings have shown a promising outlook for the use of Picoa (Pezizales) in the production of AgNPs for its use as antifungal nanodrug.

Development of nanobiomaterial for wound healing based on silver nanoparticles loaded on chitosan hydrogel.

The online version contains supplementary material available at 10.1007/s13205-021-03030-0.

Interaction Insight of Pullulan-Mediated Gamma-Irradiated Silver Nanoparticle Synthesis and Its Antibacterial Activity.

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV–Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410–420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles.

Synthesis of Isatin Derivatives Using Silver Nanoparticles as Green Catalyst: Study of Molecular Docking Interactions in SARS-CoV-2 3c-Like Protease and Determination of Cytotoxic Activities of the Compounds

The coronavirus disease (COVID-19) is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). As isatin-containing compounds exhibit several remarkable biological activities, isatin derivatives were prepared to combat the global pandemic caused by SARS-CoV-2 that is gripping the world. Herein, the synthesis of novel isatin derivatives has been reported. The cytotoxic activities of the compounds were determined using cancer cell (MCF-7) and normal cell (MCF-10A and MRC-5) lines. In silico molecular docking experiments were conducted using AutoDock Vina. We have successfully predicted the binding energies and the number of hydrogen bonds present. We have also identified the residues involved in hydrogen bond formation. The target compounds were synthesized using Schiff base following cyclization and Knoevenagel condensation reactions. We have focused on the recyclable synthesis of silver nanoparticles (AgNPs) using the extracts obtained from Dipteryx odorata. The extracts were used to reduce silver ions for the production of AgNPs. The synthesized nanoparticles exhibited excellent catalytic activities during the synthesis of isatin derivatives in ethanol. The formation of the target isatin derivatives has been confirmed using the Fourier transform-infrared (FT-IR), proton nuclear magnetic resonance (1H NMR) spectroscopy, 13C NMR spectroscopy, mass spectrometry, and elemental analysis techniques. Compound 3e was found to be the most active compound when tested against the MCF-7 cancer cell line (IC50=20.5 μM). The activity was comparable to the activities of standard doxorubicin and other compounds. In silico molecular docking experiments were conducted to study the spike protein in SARS-CoV-2 (PDB ID: 6LU7). Compound 3c exhibited high binding ability (−9.4 kcal/mol). The inhibition ability was studied using hydroxychloroquine as a standard. Results from docking studies revealed that the inhibition ability of compound 3c was higher than the inhibition abilities exhibited by other compounds. The synthesized compound 3e is a potential antiviral drug that can be used for treating the COVID-19 disease.

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.