Biosynthesis Of AgNPs Research Articles

Characterization of Asafoetida Resin Silver Nanoparticles and Efficacy of Antioxidant, Antimicrobial Inhibition

Background: In recent years, biological precursor-based synthesis, particularly plant-based green synthesis, has piqued interest in the field of nanotechnology. The plant-based approach is a promising technique for the biosynthesis of nanoparticles. 
 Aim of the study: Biosynthesis nanoparticles (AgNPs) using the ethanolic extract of a resin exuded from Ferula asafoetida (resin) and evaluate its anti actinobacterial, and antioxidant properties. 
 Method: Ferula asafoetida resin was collected and processed for ethanolic extraction by soxhlet apparatus. Preliminary phytoconstituents were quantified by GC MS and NMR. Consequently, the biosynthesis of silver nanoparticles was carried out with ethanolic extract. Characterization studies of synthesized Asafoetida AgNPs were done by UV Vis spec, XRD and SEM. Bioactivity of As-AgNPs was evaluated for anti-actinobacterial activity against selected Streptomyces toxytricini D2, Streptomyces tritici D5 and antioxidants properties were proved by Antioxidant assays. 
 Result: Ferula asafoetida resin ethanolic extract can be successfully used for the biosynthesis of Ag NPs. It showed excellent antioxidant activity, including DPPH and hydroxyl radical scavenging abilities comparable to standard ascorbic acid antioxidants. Characterized silver nanoparticles have moderate antimicrobial properties.
 Conclusion: Currently, the biosynthesis of silver nanoparticles has fostered the development of a new generation of nanoproducts as well as increased scientific promise in the nanomaterial field. Asafoetida based AgNPs as novel materials can be utilized by antioxidant, antimicrobial inhibition

EFFECIENCY OF SILVER NANOPARTICALES AS ANTIBACTERIAL AGAINST AEROMONAS HYDROPHILA ISOLATED FROM INFECTED COMMON CARP

The present investigation was carried out to investigate the antibacterial efficiency of silver nanoparticles (AgNPs) in vitro against Aeromonas hydrophila using disc diffusion assay and minimum inhibitory concentration. The pathogenic A. hydrophila was isolated from infected common carp, usually diagnosed by chemical methods, and Avitek 2 compact device were used to confirm the diagnosis. The effectiveness of the prepared AgNPs was tested by chemical and biological (green synthesis using lemon extract) methods and were diagnosed by Fourier-transform infrared spectroscopy (FTIR), UV-Visible spectroscopy, Transmission electron microscopy (TEM), scanning electron microscope (SEM), which was spherical shape of the nanosilver and the size ranged between 30-50 nm. Results of disc diffusion assay showed that the chemical synthesized of AgNPs in 18hr recorded the highest inhibition zone followed by the bio-synthesized AgNPs and Oxytetracycline respectively. After 24 hr the highest inhibition zone was registered in Oxytetracycline, however after 5 days bio-synthesized AgNPs showed the higher inhibition zone which was significantly different(P≤0.05) in comparison to other products. Based on these results, both bio and chemical synthesized of AgNPs were effectively act as antibacterial against A.hydrophila. However, green synthesis using lemon extract is considered better antibacterial with low MIC than chemical AgNPs because lemon extract is regarded eco-friendly and also the low cost product compared to chemical AgNPs synthesis.

One Pot Green Synthesis and Structural Characterisation of Bio-Silver Nanoparticles Using Prunus Persica L.

The Plant mediated green synthesis of nanoparticles has attracted more attention among the researchers due to their physicochemical and biological properties and their immense applications in environmental, biomedical, agriculture, textile, and energy storage. The biosynthesis of nanoparticles using plants provides more advantages such as easy operation, eco-friendly, utilization of non-hazardous chemicals, less temperature or energy usage, etc. when compared to physical and chemical synthesis methods. In the present study, we propose aqueous extracts from the endemic-medicinal fruit Prunus persica L. as an efficient bioproduct for the green synthesis of silver - nanoparticles (AgNPs). The biosynthesized AgNPs were characterized using UV-Visible spectroscopy, Fourier transforms Infrared spectroscopy (FTIR) High-Resolution Transmission electron microscopy (HR-TEM), Scanning electron microscopy, Atomic Force Microscopy (AFM), and X-ray diffractometer (XRD). HR-TEM gives the formation of monodispersed spherical shape with a mean diameter of 12.6 ± 3.8 nm. The SAED pattern of the nanoparticles showed that the particles were highly crystalline in nature. The purity of the synthesized AgNPs samples was studied by EDS and confirmed the presence of Ag elements corresponding to TEM images. The 2D and 3D structure images of the nanoparticle were studied and the average particle size calculation has been performed using NOVA-TX software in AFM. X-ray diffraction analysis showed that the particles were crystalline in nature with face - centered cubic structure. The antimicrobial efficacy was evaluated using the resazurin assay against both Escherichia coli and Bacillus subtilis bacteria. The antimicrobial assay of the silver nanoparticles showed higher activity against Bacillus subtilis than Escherichia coli. Results confirmed this protocol as rapid, simple, eco-friendly and alternative to conventional physical, and chemical methods.

ANTIOXIDANT ACTIVITY AND CAPACITY OF SILVER NANOPARTICLES BIOSYNTHESIS OF COMMON FRUITS AQUEOUS EXTRACTS OF THE SUNDARBAN FOREST

Fruits provide numerous health-promoting polyphenols and antioxidants. The Sundarbans mangrove forest of Bangladesh produces various fruits, and off them ten to twelve are known to be consumed or used as an ingredient in food preparations. These fruits were used in this study to evaluate the total polyphenols (TPH) contents following the method of Folin-Ciocalteu’s; and the antioxidant activity by measuring 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals scavenging, reducing power and total antioxidant capacity. Additionally, capacity of silver nanoparticles (AgNPs) biosynthesis of the fruits was determined spectrophotometrically. Sonneratia apetala fruit showed the highest TPH content (45.7 mg of gallic acid equivalent (GAE)/g powder). The fruit also showed the largest antioxidant activity attributed to the DPPH free radicals scavenging, reducing power, and total antioxidant capacity. Additionally, S. apetala fruit showed the highest capacity in the AgNPs biosynthesis (OD, 0.41; 10 mg powder/mL). Avicennia officinalis, Ceriops decandra, Heritiera fomes, and S. apetala fruits showed scavenging of 50% DPPH free radicals at 81, 34.7, 61.2, and 33.5 µg powder/mL, respectively. Contents of total polyphenols in these fruits displayed strong positive correlations with reducing power (r2 = 0.97), total antioxidant capacity (r2 = 0.85) and scavenging DPPH free radicals (r2 = 0.85) whereas that for the AgNPs biosynthesis capacity was small (r2 = 0.32). Thus, the aqueous extract of S. apetala fruit is the most potential in antioxidant activity and biosynthesis of AgNPs.

Biosynthesis of silver nanoparticles using the extract of Alpinia galanga rhizome and Rhus semialata fruit and their antibacterial activity

Biosynthesis of silver nanoparticles (AgNPs) has been reported in this study using the Ethanol extract of Alpinia galanga rhizome and Rhus semialata fruit found in Nagaland, India. The black solid phase obtained after the termination of the reaction was collected as the synthesized AgNPs which were then characterized through FT-IR, UV–vis spectroscopy, XRD, SEM, TEM, SAED and EDX studies. XRD studies revealed the nanocrystalline phase and cubic structure of the synthesized AgNPs. The particle size of the synthesized AgNPs ranged from 10.732 nm to 34.927 nm with an average diameter of 17.625 nm for Alpinia galanga extract and 10.264 nm to 16.441 nm with an average diameter of 7.289 nm for Rhus semialata extract. The phytochemical screening and FT-IR spectra revealed the presence of carbohydrate, flavonoid, phenol, protein, and tannin. The antibacterial activity of the synthesized AgNPs was also investigated in vitro showing a comparable activity against Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus. Maximum inhibition was shown by AgNPs of Rhus semialata extract against Bacillus subtilis with an inhibition zone of 15 mm. The antibacterial study showed promising results for their possible application in the pharmaceutical and medical industries.

Efficacy of Calotropis gigantea L. flower extract and biosynthesized silver nanoparticles against fungal pathogens

Following the emergence of resistant fungal pathogens, plants mediated biosynthesized silver nanoparticles (AgNPs) have been recognized as promising tools to combat fungal pathogens. This study evaluated the potency of Calotropis gigantea L. in producing AgNPs followed by testing their antifungal effects against fungal pathogens. AgNPs were successfully produced utilizing the aqueous extract of C. gigantea flower extract. The biosynthesized AgNPs were characterized by UV-Vis spectroscopy, SEM, EDX and XRD analyzes. The visible brown color validated the synthesis of AgNPs and the UV-Vis spectrum revealed a maximum absorption at 438 nm. The SEM and EDX analyzes revealed that the AgNPs were rod shaped ranging from 10 nm to 150 nm in size along with the presence of elemental Ag. The X-ray diffraction further indicated that the biosynthesized AgNPs were crystalline in nature. The C. gigantea flower extract and biosynthesized AgNPs effectively mitigate the fungal growth viz.: Aspergillus aculeatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Cryptococcus neoformans, Phialophora verrucosa and Sporothrix schenckii. The maximum inhibition in growth by biosynthesized AgNPs was observed against P. verrucosa (13 mm) whereas the flower extract of C. gigantea was most effective against P. verrucosa (14.5 mm) and S. schenckii (13.5 mm). These findings may suggest C. gigantea flower extract as a green solution for biosynthesizing AgNPs with tremendous potentiality towards controlling human and plant pathogenic fungus.

Single-step biogenic synthesis of silver nanoparticles using honeybee-collected pollen

In this work, we describe a simplified and bottom-up synthesis of silver nanoparticles (AgNPs) using pollen collected by Andean honeybees as a natural reducing and capping agent for the first time. The biosynthesized AgNPs were characterized by their optical properties, electrochemical properties, average size, morphology, and purity by various analytical techniques. The synthesized AgNPs were spherical, having 10–35 nm size, showed λmax at 440 nm, well dispersed, and remained stable for up to 1 month under laboratory conditions without any sedimentation. Moreover, we also investigated the usability of synthesized AgNPs as antioxidants against 1, 1-diphenyl-2-picrylhydrazyl (DPPH). Thus, this protocol may be adapted for the large-scale production of nanoparticles without the use of chemical solvents and supports the importance of local resources in green chemistry.

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.

Detect the Antibacterial and Antitumor of synthesized Silver Nanoparticles Using Microbacterium sp.

Metal nanoparticles are widely utilized in biotechnology and biomedicine for various applications, including medication delivery, imaging, and bacterial growth control. Silver nanoparticles (AgNPs) were synthesized by bacteria, fungi, algae, and plants. The Study aimed to synthesize nanomaterial with a cost-effective, environmentally friendly, and the uses of AgNPs as antibacterial (against pathogenic bacteria) and anticancer (on MCF7 cell line). In this Study, bacteria were collected from different soil samples. Isolated, purified by selective media, identification genotypically by 16rRNA sequencing analysis, then compared with NCBI, GenBank as Microbacterium sp. Biosynthesis of silver nanoparticles using Microbacterium for extracellular synthesis by reducing silver ions to silver nanoparticles. The color change to brown and reddish-brown was the first indication of the AgNPs formation; physical characterization using UV-Visible spectroscopy showed a wavelength in 489 nm, while X-ray diffraction (XRD) revealed that the silver nanoparticles were crystalline; transmission electron microscope (TEM) image showed that AgNPs spherical in shape with an average diameter of around 50 nm, in SEM (Scanning electron microscope) AgNPs formed with a diameter of 41-44 nm, spherical and uniform, while Energy-dispersive X-ray show very high silver peaks. Bioactivity of AgNPs by antimicrobial on pathogenic bacteria, which collected from Al- Sadr hospital in Misan (identified by using VITEK). This experiment showed that the inhibition zone was rung from (6- 38mm) on pathogenic bacteria; it was tremendous compared with antibiotics (Gentamycin in this project ranged from(7-28.5mm). Antitumor activity of extracellular biosynthesized AgNPs was determined using the MTT test against breast cancer cells (MCF7 cell line), which showed very high results. AgNPs inhibition breast cancer cell line by about 81% at 100ug/ml, indicating that the rate is outstanding. Finally, different biomedical approaches can benefit from AgNPs as antibacterial agents and anticancer agents with many results. Keywords. Silver Nanoparticles, Biosynthesis, Antibacterial, and Antitumor.

Silver nanoparticles induce mitochondria-dependent apoptosis and late non-canonical autophagy in HT-29 colon cancer cells

Abstract The interactions of nanomaterials with biological materials such as immortalized cell lines are recently on the rise. Owing to this superiority, the biosynthesis of AgNPs using gallic acid as a reductant was implemented in this study. After being synthesized, the AgNPs were characterized using techniques such as dynamic light scattering, transmission electron microscopy, selected area electron diffraction, and X-ray diffraction methods. Furthermore, the AgNPs were assessed for their cytotoxic effects on the colorectal adenocarcinoma cell line HT-29. The mechanisms of such cell-killing effect were investigated by analyzing the expressions of 14 mRNAs using quantitative polymerase chain reaction. The outcomes indicate that the synthesized AgNPs were cytotoxic on HT-29 cells. The expressions of all apoptotic genes analyzed including cyt-C, p53, Bax, Bcl2, CASP3, CASP8, CASP9, and CASP12 were upregulated. With regard to the autophagy-related genes, Beclin-1, XBP-1, CHOP, and LC3-II were upregulated, whereas the expressions of ATG3 and ATG12 were downregulated. To conclude, the AgNPs induced mitochondria-dependent apoptosis and non-canonical autophagy in HT-29 cells. A crosstalk did occur between autophagy and apoptosis in such a cell-killing effect. Hence, further studies are required to elucidate the exact mechanisms in animal models for further use of AgNPs in clinical medicine for the treatment of neoplasms of the digestive tract.

Biosynthesis of silver nanoparticles using three different fruit extracts: Characterization, formation mechanism and estrogen removal

Plant-mediated synthesis of silver nanoparticles (Ag NPs) is a green and economically viable method, which can offer numerous benefits over traditional chemical and physical methods. In this paper, three fruit extracts (tomato, orange, and grapefruit) served simultaneously as stabilizing and reducing agents during the biosynthesis of Ag NPs. The formation of Ag NPs, were monitored using the UV–visible absorption spectra of Ag NPs which exhibited three distinct bands centered at 439, 413, and 410 nm. SEM and TEM analysis indicated that these bands corresponded to three distinct spherical-shaped Ag NPs having average particle sizes of 73, 24, and 31 nm, respectively. XRD and EDS spectral analyses were used to verify the degree of crystallinity, nanostructure, and presence of Ag NPs. Advanced analysis using XPS, FTIR, and GC-MS indicated that the Ag NPs were coated with a variety of organic compounds including acids, aldehydes, esters, and ketones, indicating that fruit derived phytochemicals had a significant role in synthesis, and subsequently a mechanism of Ag NPs formation was proposed. The fabricated nanoparticles were also successfully used in Fenton-like oxidation for the environmental remediation of estrone and estriol, with removal efficiencies of 52.1 and 35.9%, respectively.

First Report of the Biosynthesis and Characterization of Silver Nanoparticles Using Scabiosa atropurpurea subsp. maritima Fruit Extracts and Their Antioxidant, Antimicrobial and Cytotoxic Properties.

Candida and dermatophyte infections are difficult to treat due to increasing antifungal drugs resistance such as fluconazole, as well as the emergence of multi-resistance in clinical bacteria. Here, we first synthesized silver nanoparticles using aqueous fruit extracts from Scabiosa atropurpurea subsp. maritima (L.). The characterization of the AgNPs by means of UV, XRD, FTIR, and TEM showed that the AgNPs had a uniform spherical shape with average sizes of 40–50 nm. The biosynthesized AgNPs showed high antioxidant activity when investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The AgNPs displayed strong antibacterial potential expressed by the maximum zone inhibition and the lowest MIC and MBC values. The AgNPs revealed a significant antifungal effect against the growth and biofilm of Candida species. In fact, the AgNPs were efficient against Trichophyton rubrum, Trichophyton interdigitale, and Microsporum canis. The antifungal mechanisms of action of the AgNPs seem to be due to the disruption of membrane integrity and a reduction in virulence factors (biofilm and hyphae formation and a reduction in germination). Finally, the silver nanoparticles also showed important cytotoxic activity against the human multiple myeloma U266 cell line and the human breast cancer cell line MDA-MB-231. Therefore, we describe new silver nanoparticles with promising biomedical application in the development of novel antimicrobial and anticancer agents.

Biosynthesis of Silver Nanoparticles from Cymbopogon citratus Leaf Extract and Evaluation of Their Antimicrobial Properties

Background: Silver nanoparticles (AgNPs) are toxic to microorganisms and can potentially kill multidrug-resistant bacteria. Nanoparticles can be synthesized in many ways, such as physical or chemical methods. Recently, it has been found that plant molecules can perform the same reduction reactions necessary for the production of nanoparticles but in a much more efficient way. Results: Here, green chemistry was employed to synthesize AgNPs using leaf extracts of Cymbopogon citratus. The effects of different parameters such as temperature, pH, and the volume of plant extract were also tested using their absorbance pattern at different wavelengths. The Surface Plasmon Resonance (SPR) changed with the changes in parameters. Changes in temperature from 20 °C to 60 °C have changed the highest absorbance from 0.972 to 3.893 with an SPR of 470 nm. At higher pH (11.1), the particles become highly unstable and have irregular shapes and sizes. The peak shifts to the right at a lower pH level (3.97), indicating a smaller but unstable compound. We have also investigated the effect of the volume of plant extracts on the reaction time. The sample with the highest amount of plant extract showed the most absorbance with a value of 0.963 at λmax, calculated to be 470 nm. The total formation of the AgNPs was observed visually with a color change from yellow to brownish-black. UV-visible spectroscopy was used to monitor the quantitative formation of AgNPs, showing a signature peak in absorbance between 400 and 500 nm. We have estimated the size of the nanoparticles as 47 nm by comparing the experimental data with the theoretical value using Mieplot. The biosynthesized AgNPs showed enhanced antibacterial activity against several multidrug-resistant bacteria, determined based on the minimal inhibitory concentration and zone of inhibition. Conclusion: The findings of this study indicate that an aqueous extract of C. citratus can synthesize AgNPs when silver nitrate is used as a precursor, and AgNPs act as antimicrobial property enhancers, which can be used to treat antibiotic-resistant bacteria. Hence, mass production and green synthesis of AgNPs from C. citratus will be able to increase the overall health of the general population. Moreover, it will enormously reduce the costs for drug development and provide employment options in the remotely located source areas. Finally, our findings will influence further studies in this field to better understand the properties and applications of AgNPs and ultimately contribute to improving planetary health by increasing immunity with high biocompatibility and less drug toxicity.

Probiotic-Mediated Biosynthesis of Silver Nanoparticles and Their Antibacterial Applications against Pathogenic Strains of Escherichia coli O157:H7.

The present study aimed to suggest a simple and environmentally friendly biosynthesis method of silver nanoparticles (AgNPs) using the strain Bacillus sonorensis MAHUQ-74 isolated from kimchi. Antibacterial activity and mechanisms of AgNPs against antibiotic-resistant pathogenic strains of Escherichia coli O157:H7 were investigated. The strain MAHUQ-74 had 99.93% relatedness to the B. sonorensis NBRC 101234T strain. The biosynthesized AgNPs had a strong surface plasmon resonance (SPR) peak at 430 nm. The transmission electron microscope (TEM) image shows the spherical shape and size of the synthesized AgNPs is 13 to 50 nm. XRD analysis and SAED pattern revealed the crystal structure of biosynthesized AgNPs. Fourier transform infrared spectroscopy (FTIR) data showed various functional groups associated with the reduction of silver ions to AgNPs. The resultant AgNPs showed strong antibacterial activity against nine E. coli O157:H7 pathogens. Minimum inhibitory concentration (MIC) values of the AgNPs synthesized by strain MAHUQ-74 were 3.12 μg/mL for eight E. coli O157:H7 strains and 12.5 μg/mL for strain E. coli ATCC 25922. Minimum bactericidal concentrations (MBCs) were 25 μg/mL for E. coli O157:H7 ATCC 35150, E. coli O157:H7 ATCC 43895, E. coli O157:H7 ATCC 43890, E. coli O157:H7 ATCC 43889, and E. coli ATCC 25922; and 50 μg/mL for E. coli O157:H7 2257, E. coli O157: NM 3204-92, E. coli O157:H7 8624 and E. coli O157:H7 ATCC 43894. FE-SEM analysis demonstrated that the probiotic-mediated synthesized AgNPs produced structural and morphological changes and destroyed the membrane integrity of pathogenic E. coli O157:H7. Therefore, AgNPs synthesized by strain MAHUQ-74 may be potential antibacterial agents for the control of antibiotic-resistant pathogenic strains of E. coli O157:H7.

Aplikasi Antibakteri Nanopartikel Perak (NPAg) Hasil Biosintesis dengan Ekstrak Air Daun Kemangi

Nanotechnology is a technology that can be used to overcome several environmental problems. Synthesis of silver nanoparticles (AgNPs) mediated with basil leaf bioreductant with a concentration 0.5% at a temperature of 25⁰C has been carried out. The result of biosynthesis of AgNPs was analyzed using a UV-Vis spectrophotometer in which the SPR band showed the maximum wavelength of 429 nm. The size of AgNPs was determined by a Particle Size Analyzer (PSA), which its size was 86.83 nm. The morphology and elemental content of AgNPs were confirmed using SEM-EDS showing that the shape of AgNPs was irregularly spherical crystals while the EDS results showed a dominant peak at 3 keV indicating silver content. AgNPs showed strong antibacterial activity against Escherechia coli and moderate against Staphylococcus aureus.

Facile Green Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Origanum majorana with Potential Bioactivity against Multidrug Resistant Bacterial Strains

The high prevalence of nosocomial bacterial resistance contributes to significant mortality and morbidity around the world; thus, finding novel antibacterial agents is of vital concern. Accordingly, the present study attempted to synthesize silver nanoparticles (AgNPs) using a green approach. Aqueous leaf extract of Origanum majorana was used to synthesize AgNPs and the antibacterial efficiency against multidrug resistant bacterial strains was detected. Characterization of the biogenic AgNPs was performed using ultraviolet-visible spectrophotometry (UV-Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR) analysis, and X-ray diffraction analysis (XRD). The disc diffusion method was used to detect the antibacterial activity of AgNPs against three nosocomial multidrug-resistant strains. Preliminary UV-Vis analysis revealed the biosynthesis of AgNPs due to peak formation at 374 nm, corresponding to the surface plasmon resonance (SPR) of biogenic AgNPs. TEM micrographs detected the synthesis of small AgNPs with an average particle size of 26.63 nm. EDX analysis revealed the presence of the following elements: oxygen (3.69%), carbon (2.93%), aluminum (1.29), silicon (2.83%), chloride (17.89%), and silver (71.37%). Furthermore, XRD analysis revealed the presence of diffraction peaks at 2 theta (θ) degrees of 38.18°, 44.36°, 64.35°, and 77.54°, assigned to the planes of silver crystals (111), (200), (220), and (311), respectively. Collectively, these findings affirm the synthesis of biogenic AgNPs with potential physicochemical characteristics. The antimicrobial efficiency of the biogenic AgNPs indicated that Klebsiella pneumoniae strain was the most susceptible strain at concentrations of 50 and 100 µg/disk, with inhibitory zones of 21.57 and 24.56 mm, respectively. The minimum inhibitory concentration (MIC) of AgNPs against Klebsiella pneumoniae strain was found to be 10 µg/mL, while the minimum bactericidal concentration (MBC) was found to be 20 µg/mL. In conclusion, aqueous leaf extract of O. majorana mediated synthesis of small sized AgNPs, with potential antimicrobial effectiveness against multidrug-resistant bacterial pathogens.

Optimization of Bacillus subtilis growth parameters for biosynthesis of silver nanoparticles by using response surface methodology

Silver nanoparticles (AgNPs) are among the most widely biosynthesized and used nanomaterials. They have different unique properties and a wide range of applications. This study is concerned with optimization of the growth conditions of Bacillus subtilis NRC1 for the biosynthesis of AgNPs using two designs of response surface methodology (RSM) statistical analysis. The data obtained from Plackett-Burman design (PBD) followed by central composite design (CCD), showed a good agreement between the experimental and predicted values of AgNPs biosynthesis. The optimum conditions were 0.7% (w/v) casein hydrolysate, 5% dextrin (w/v), pH 7.5 and 57 × 106 CFU/ml inoculum size. The model was highly valid and could be applied with a confidence factor of 99.47%. Minimal inhibitory concentration (MIC) of these AgNPs synthesized using the extracellular filtrate after growth of Bacillus subtilis NRC1 in the optimized medium was found to be 41–43µg/ml for all tested microorganisms with exception of Pseudomonas aeruginosa where MIC was 169 µg/ml.

Green synthesis and characterization of silver nanoparticles from Acacia nilotica and their anticancer, antidiabetic and antioxidant efficacy

Both cancer and diabetes mellitus are serious health issues, accounting more than 11 million deaths worldwide annually. Targeted use of plant-mediated nanoparticles (NPs) in treatment of ailments has outstanding results due to their salient properties. The current study was designed to investigate the safe production of silver nanoparticles (AgNPs) from Acacia nilotica. Different concentrations of AgNO3 were tested to optimize the protocol for the synthesis of AgNPs from the bark extract. It was demonstrated that 0.1 M and 3 mM were found to be the optimum concentrations for the synthesis of AgNPs. Standard characterization techniques such as UV–vis spectrophotometry, SEM, SEM-EDX micrograph, spot analysis, elemental mapping and XRD were used for the conformation of biosynthesis of AgNPs. Absorption spectrum of plant-mediated AgNPs under UV–vis spectrophotometer showed a strong peak at 380 nm and 420 nm for AgNPs synthesized at 0.1 M and 3 mM concentration of salt. The SEM results showed that AgNPs were present in variable shapes within average particle size ranging from (20–50 nm). Anticancer, antidiabetic and antioxidant potential of green AgNPs was investigated and they showed promising results as compared to the positive and negative controls. Hence, AgNPs were found potent therapeutic agent against the human liver cancer cell lines (HepG2), strong inhibitor for α-glucosidase enzyme activity and scavenging agent against free radicals that cause oxidative stress. Further studies are however needed to confirm the molecular mechanism and biochemical reactions responsible for the anticancer and antidiabetic activities of the particles.

Impact of temperature and pH on antioxidant activity of green silver nanoparticles fabricated from Ananas comosus peel extracts

Abstract Silver nanoparticles arose as a new weapon in the development of green synthesis of these nanoparticles using diverse natural resources such as plant leaf, microorganisms, and fruit extracts. Biosynthesis approach by using waste materials from plant is widely used as it is proven to be environmentally and cost friendly method. This study aims to identify the impact of temperature and pH on antioxidant activities of silver nanoparticles fabricated from pineapple (Ananas comosus) peel extract. Different temperature (70°C, 80°C and 90°C) and pH (7, 8 and 9) have been tested to the samples and characterized using UV-Visible Spectroscopy. Then, antioxidant activities of the AgNPs produced using different temperature and pH were determined using free radical scavenging ability on 2,2-diphenyl-2-picrylhydrazyl (DPPH). The results were found at pH 9, the surface plasmon resonance peak for biosynthesized AgNPs was at 425 nm on Day 2 while other treatments took longer time to exhibit the AgNPs peak. Biosynthesized AgNPs treated at temperature 90°C showed the optimum temperature when it exhibited peak at 420 nm on Day 3. The biosynthesized of AgNPs from pineapple peel extracts exhibited potential antioxidant activity in the DPPH scavenging by highest DPPH scavenging percentage is at 84.75% for AgNPs treated at pH 9 and 80.29 % for AgNPs treated at 90°C with concentration of 1000 µg/mL. Temperature and pH gave significant impact in synthesis and increase antioxidant activity of green silver nanoparticles.

Rapid biogenic fabrication of silver nanoparticles using Ziziphus nummularia under optimised conditions and evaluation of their antimicrobial synergy

Nanotechnology deals with the Nanoparticles having a size of 1-100 nm in one dimension used significantly concerning medical chemistry, atomic physics, and all other known fields. These particles can be prepared easily by different physical, chemical and biological approaches. But the biological approach is the most emerging approach of preparation because this method is easier than the other methods, eco-friendly and less time consuming. In this study green synthesis of silver nanoparticles (AgNPs) of Ziziphus nummularia (ZN) was done using the magnetic stirrer method. These AgNPs were characterized by UV-vis Spectroscopy, FTIR and SEM technique and the optimization was done by varying the root extract volume, silver nitrate concentrations, pH and temperature. It was observed that ZN extract can reduce the silver ions in to AgNPs with in 30 min of reaction time. The surface plasmon resonance peak observed near 430 nm, confirmed the reduction of Ag+ to Ag0 . Maximum absorbance peak 430 nm was observed with 2mM AgNO3 solution with standard condition of 9pH and 70°C temp. at magnetic stirrer followed by 42 hrs incubation during the optimization of stable AgNPs. SEM images clearly shows that synthesized AgNPs are in spherical shape with size range 20-50 nm. FTIR clearly indicating the presence of capping and reducing agents around the AgNPs synthesised from crude extract of ZN. The biosynthesized AgNPs exhibited significant antimicrobial activity against pathogenic Staphylococcus aureus, Enterococcus faecalis (a Gram-positive bacterium), Pseudomonas aeruginosa and Escherichia coli (a gram negative bacterium) and Aspergillus niger (plant pathogenic fungal strain), Candida albicans (human pathogenic fungal strain). This novel approach of bionanotechnology can be taken up by the researcher in near future to develop the effective bionaomedicine, biopesticides, nanofood composites etc.