Antimycobacterial, Anticancer, Antioxidant and Photocatalytic Activity of Biosynthesized Silver Nanoparticles Using Berberis Integerrima

Synthesis and its characterisation of selenium/silver/chitosan and cellular toxicity against liver carcinoma cells studies

Liver cancer is one of the most common lethal malignancy in the world. To treat liver cancer, new cure options are crucial. The use of natural substances along nanosciences may provide healing with lower toxicity and a smaller amount of side properties. In this research, The three-component selenium-silver-chitosan nanocomposite (Se-Ag-CS NCs) were synthesised with the help of ultrasound in a stepwise manner. The as-synthesised Se-Ag-CS NCs were characterised accordingly by applying powder X-Ray diffraction (PXRD), Fourier transforms infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive x-ray analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and potential. The PXRD demonstrated that the NCs were synthesised successfully and the grain sizes of 27.3 were obtained. The FESEM and TEM analyses have shown the NCs have a nano-sized structure with spherical and rod-like morphologies in a coating of CS. The DLS analysis also revealed that NCs were synthesised in nanoscale particles. The NCs' surface charge was also positive due to the presence of chitosan. Different concentrations of NCs (0, 0.125, 0.250, 0.500, and 1 mg/ml) were tested at different times (24, 48, and 72 h) to measure cytotoxicity against liver cancer cells. The results showed at a concentration of 1 mg/mL in 72 h, the most toxicity effects were applied to liver cancer cells. Moreover, the results indicated NCs can inhibit the growth of cancer cells in a dose-dependent manner, while the toxicity of nanocomposite on normal cells was less. It is important to create nanocomposites derived from natural polymers as a new strategy in cancer treatment that can fight cancer cells while having low toxicity for normal cells. Therefore, the present results can be considered in improving cancer-fighting methods.

Ferula latisecta gels for synthesis of zinc/silver binary nanoparticles: antibacterial effects against gram-negative and gram-positive bacteria and physicochemical characteristics

This study explores the potential antibacterial applications of zinc oxide nanoparticles (ZnO NPs) enhanced with silver (Ag) using plant gel (ZnO-AgO NPs). The problem addressed is the increasing prevalence of pathogenic bacteria and the need for new, effective antimicrobial agents. ZnO NPs possess distinctive physicochemical properties that enable them to selectively target bacterial cells. Their small size and high surface area-to-volume ratio allow efficient cellular uptake and interaction with bacterial cells. In this study, the average size of the synthesized ZnO-Ag nanoparticles was 77.1 nm, with a significant standard deviation of 33.7 nm, indicating a wide size distribution. The nanoparticles demonstrated remarkable antibacterial efficacy against gram-negative and gram-positive bacteria, with inhibition zones of 14.33 mm for E. coli and 15.66 mm for B. subtilis at a concentration of 300 µg/ml. Minimum inhibitory concentrations (MIC) were determined to be 100 µg/ml for E. coli and 75 µg/ml for S. saprophyticus. Additionally, ZnO-Ag NPs exhibited excellent biocompatibility, making them appropriate for various pharmacological uses. This study utilizes Ferula latisecta gels, offering a sustainable and eco-friendly approach to nanoparticle synthesis. Incorporating of Ag into ZnO NPs significantly enhances their antimicrobial properties, with the combined results showing great inhibition effects on pathogenic microbes. The findings suggest that ZnO-Ag NPs could be a promising candidate for addressing the challenges posed by drug-resistant bacterial infections and enhancing antimicrobial treatments.

Silver and gold nanoparticles: Eco-friendly synthesis, antibiofilm, antiviral, and anticancer bioactivities

For the first time in this study, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were green synthesized by the cost-effective and eco-friendly procedure using Cotton seed meal and Fodder yeast extracts. The biosynthesized NPs were characterized by UV-Vis spectroscopy, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and fourier-transform infrared (FTIR) spectroscopy. Furthermore, the biosynthesized NPs were tested in vitro against biofilm formation by some pathogenic negative bacteria (Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., and Pseudomonas aeruginosa) and negative bacteria (staphylococcus aureus) as well as against human denovirus serotype 5 (HAdV-5) and anticancer activity using HepG2 hepatocarcinoma cells. UV-Vis absorption spectra of reaction mixture of AgNPs and AuNPs exhibited maximum absorbance at 440 nm and 540 nm, respectively. This finding was confirmed by DLS measurements that the highest intensity of the AgNPs and AuNPs were 84 nm and 73.9 nm, respectively. FTIR measurements identified some functional groups detected in Cotton seed meal and Fodder yeast extracts that could be responsible for reduction of silver and gold ions to metallic silver and gold. The morphologies and particle size of AgNPs and AuNPs were confirmed by the TEM and SAED pattern analysis. Biosynthesized AgNPs and AuNPs showed good inhibitory effects against biofilms produced by Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., Pseudomonas aeruginosa, and Staphylococcus aureus. In addition, they showed anticancer activities against hepatocellular carcinoma (HepG-2) and antiviral activity against human adenovirus serotype 5 infection in vitro. Finally, the results of this study is expected to be extremely helpful to nano-biotechnology, pharmaceutical, and food packing applications through developing antimicrobial and/or an anticancer drugs from ecofriendly and inexpensive nanoparticles with multi-potentiality.

Antimicrobial and antibiofilm properties of selenium-chitosan-loaded salicylic acid nanoparticles for the removal of emerging contaminants from bacterial pathogens

In this study salicylic acid loaded containing selenium nanoparticles was synthesized and called SA@CS-Se NPs. the chitosan was used as a natural stabilizer during the synthesis process. Fourier transforms infrared spectroscopy (FTIR), Powder X-ray diffraction (XRD), field emission electron microscopy (FESEM), and transmission electron microscopy (TEM) were used to describe the physicochemical characteristics of the SA@CS-Se NPs. The PXRD examination revealed that the grain size was around 31.9 nm. TEM and FESEM techniques showed the spherical shape of SA@CS-Se NPs. Additionally, the analysis of experiments showed that SA@CS-Se NPs have antibacterial properties against 4 ATCC bacteria; So that with concentrations of 75, 125, 150, and 100 µg/ml, it inhibited the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus respectively. Also, at the concentration of 300 µg/ml, it removed 22.76, 23.2, 10.62, and 18.08% biofilm caused by E. coli, P. aeruginosa, B. subtilis, and S. aureus respectively. The synthesized SA@CS-Se NPs may find an application to reduce the unsafe influence of pathogenic microbes and, hence, eliminate microbial contamination.

The effects of titanium dioxide (TiO2) nanoparticles on physiological, biochemical, and antioxidant properties of Vitex plant (Vitex agnus - Castus L)

Titanium dioxide nanoparticles (TiO2NPs) are widely used in agriculture in order to increase the yield and growth characteristics of plants. This study investigated the effects of TiO2NPs on photosynthetic pigments and several biochemical activities and antioxidant enzymes of the Vitex plant. Different concentrations of nanoparticles (0, 200, 400, 600 and 800 ppm) at five levels were sprayed on Vitex plants on the 30th day of the experiment. TiO2NPs at different concentrations had positive effects on root and shoot dry weight and a negative effect on leaf dry weight. The amount of chlorophyll increased with the concentration of TiO2NPs; however, the amount of chlorophyll b showed a decreasing trend while the total chlorophyll had a constant trend. The highest amount of soluble sugar was obtained in the treatment of 200 ppm nanoparticles. The application of TiO2NPs did not have any effect on the content of proline and soluble proteins of Vitex plant. The effects of foliar TiO2NPs, compared to the control, showed a significant increase in the activity of antioxidant enzymes. In general, TiO2NPs had a favorable effect on dry matter production and some antioxidant and biochemical properties of the Vitex plant.

Statistical optimization, characterization, antioxidant and antibacterial properties of silver nanoparticle biosynthesized by saw palmetto seed phenolic extract

On the global market, silver nanoparticles (Ag-NPs) are in high demand for their various applications in biomedicine, material engineering, and consumer products. This study highlighted the biosynthesis of the Ag-NPs using saw palmetto seed phenolic extract (SPS-phenolic extract), which contained vital antioxidant-phenolic compounds. Herein, central composite statistical design, response surface methodology, and sixteen runs were conducted to optimize Ag-NPs biosynthesis conditions for maximizing the production of Ag-NPs and their phenolic content. The best-produced SPS-Ag-NPs showed a surface plasmon resonance peak at 460 nm and nano-spherical sizes ranging from 11.17 to 38.32 nm using the UV spectrum analysis and TEM images, respectively. The produced SPS-Ag-NPs displayed a high negative zeta-potential value (- 32.8 mV) demonstrating their high stability. The FTIR analysis demonstrated that SPS-phenolic compounds were involved in sliver bio-reduction and in stabilizing, capping, and preventing Ag-NP aggregation. The thermogravimetric investigation revealed that the produced SPS-Ag-NPs have remarkable thermal stability. The produced SPS-Ag-NP exceeded total antioxidant activity (13.8 µmol Trolox equivalent) more than the SPS-phenolic extract (12.0 µmol Trolox equivalent). The biosynthesized SPS-Ag-NPs exhibited noticeably better antibacterial activity against multidrug-resistant Gram-negative E. coli and Gram-positive S. aureus compared to SPS-phenolic extract. Hence, the bio-synthesized SPS-Ag-NPs demonstrated great potential for use in biomedical and antimicrobial applications.

Exploring the Biomedical Applications of Biosynthesized Silver Nanoparticles Using Perilla frutescens Flavonoid Extract: Antibacterial, Antioxidant, and Cell Toxicity Properties against Colon Cancer Cells

The present study reports the biomimetic synthesis of silver nanoparticles (AgNPs) using a simple, cost effective and eco-friendly method. In this method, the flavonoid extract of Perilla frutescens (PFFE) was used as a bioreduction agent for the reduction of metallic silver into nanosilver, called P. frutescens flavonoid extract silver nanoparticles (PFFE-AgNPs). The Ultraviolet-Visible (UV-Vis) spectrum showed a characteristic absorption peak at 440 nm that confirmed the synthesis of PFFE-AgNPs. A Fourier transform infrared spectroscopic (FTIR) analysis of the PFFE-AgNPs revealed that flavonoids are involved in the bioreduction and capping processes. X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns confirmed the face-centered cubic (FCC) crystal structure of PFFE-AgNPs. A transmission electron microscopic (TEM) analysis indicated that the synthesized PFFE-AgNPs are 20 to 70 nm in size with spherical morphology and without any aggregation. Dynamic light scattering (DLS) studies showed that the average hydrodynamic size was 44 nm. A polydispersity index (PDI) of 0.321 denotes the monodispersed nature of PFFE-AgNPs. Further, a highly negative surface charge or zeta potential value (-30 mV) indicates the repulsion, non-aggregation, and stability of PFFE-AgNPs. PFFE-AgNPs showed cytotoxic effects against cancer cell lines, including human colon carcinoma (COLO205) and mouse melanoma (B16F10), with IC50 concentrations of 59.57 and 69.33 μg/mL, respectively. PFFE-AgNPs showed a significant inhibition of both Gram-positive (Listeria monocytogens and Enterococcus faecalis) and Gram-negative (Salmonella typhi and Acinetobacter baumannii) bacteria pathogens. PFFE-AgNPs exhibited in vitro antioxidant activity by quenching 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2) free radicals with IC50 values of 72.81 and 92.48 µg/mL, respectively. In this study, we also explained the plausible mechanisms of the biosynthesis, anticancer, and antibacterial effects of PFFE-AgNPs. Overall, these findings suggest that PFFE-AgNPs have potential as a multi-functional nanomaterial for biomedical applications, particularly in cancer therapy and infection control. However, it is important to note that further research is needed to determine the safety and efficacy of these nanoparticles in vivo, as well as to explore their potential in other areas of medicine.

Biosynthesis of ZnO.Ag2O3 using aqueous extract of Haplophyllum obtusifolium: Characterization and cell toxicity activity against liver carcinoma cells

The zinc oxide‐silver oxide nanocomposite (ZnO.Ag2O3 particles) was prepared by using an aqueous plant extract of Haplophyllum obtusifolium for the first time. Powder X‐ray diffraction (PXRD), Fourier transforms spectroscopy (FTIR), field emission microscopy (FESEM), energy dispersive X‐ray analysis (EDX), and transmission electron microscopy (TEM) were applied to analyze the structure, functional groups, morphology, and purity of the prepared nanocomposite. PXRD revealed the formulation of ZnO.Ag2O3 for the particles. The investigation of functional groups has demonstrated the presence of some carbonated impurities along with absorbed water in the composition of the ZnO.Ag2O3 nanocomposite. Morphologically, particles have formed a petal‐like shape with different sizes. The EDX analysis also confirmed the composition of the prepared sample and the presence of 4.78% silver in the formula. Additionally, the TEM analysis revealed spherical and rectangular shapes with a particle size of 80.43 ± 46.73 nm. Moreover, the ZnO.Ag2O3 particles were used against cancer cells, which has shown synthesized NCs have a toxic effect against liver cancer cells in a concentration and time‐dependent manner.

Effect of deficit irrigation on physiological, biochemical, and yield characteristics in three baby corn cultivars (Zea mays L.)

The main problem in the production of crops in arid and semi-arid regions of the world is the lack of water and its effect on the plant in the form of drought stress. Cultivation of key crops such as corn, which also requires a lot of water, is not possible in these areas except by applying water consumption management methods. Among the most important of these methods is deficit irrigation. The effect of deficit irrigation on relative water content (RWC), malondialdehyde (MDA), compatible osmolytes (proline and soluble sugars), antioxidant enzymes, and yield was studied in three baby corn cultivars in a field experiment using a randomized complete block design (RCBD) with split-plots and three replications. Three levels of deficit irrigation (0, 20, and 40% deficit) constituted the main plots and three cultivars of baby corn (Challenger, Basin, and Passion) constituted the sub plots. Analysis of variance showed that deficit irrigation had a significant effect on all variables. Cultivar (Challenger, Basin and Passion) had a significant effect on proline (0%, 41.5% and 73.2%), carbohydrates (23.9%, 15.4% and 0%), and MDA content (0%, 26.1% and 41.2%), as well as peroxidase (POD) (0%, 136.1% and 227.9%) levels respectively. The interaction between deficit irrigation and cultivar had a significant effect on proline, carbohydrates, and POD. RWC decreased (26.9, 6.5 and 0%) with increasing irrigation deficit (0, 20 and 40%) respectively while proline (0, 23.7 and 64.8%), carbohydrates (0, 29.7 and 34.09%), catalase (CAT) (0, 20.8 and 70.1%), and POD (0, 55.05 and 113.2%) increased under the same conditions. Carbohydrate content was higher in the Basin and Challenger cultivars (21.71 and 19.07) and proline (145.9), POD (193.9), and MDA content (8.53) were higher in the Passion cultivar. Among the studied cultivars, the highest yield was achieved by the Passion cultivar (37.02 and 62.9% more than Challenger and Basin cultivars respectively). In general, the results showed that drought stress caused an increase in compatible osmolyte content and the activity of antioxidant enzymes. However, this increase could not offset the effects of drought stress on yield in the 40% deficit treatment.

Extracellular biosynthesis, OVAT/statistical optimization, and characterization of silver nanoparticles (AgNPs) using Leclercia adecarboxylata THHM and its antimicrobial activity

BACKGROUND

The biosynthesis of silver nanoparticles (AgNPs) is an area of interest for researchers due to its eco-friendly approach. The use of biological approaches provides a clean and promising alternative process for the synthesis of AgNPs. We used for the first time the supernatant of Leclercia adecarboxylata THHM under optimal conditions to produce AgNPs with an acceptable antimicrobial activity against important clinical pathogens.

RESULTS

In this study, soil bacteria from different locations were isolated and screened for their potential to form AgNPs. The selected isolate, which was found to have the ability to biosynthesize AgNPs, was identified by molecular methods as Leclercia adecarboxylata THHM and its 16S rRNA gene was deposited in GenBank under the accession number OK605882. Different conditions were screened for the maximum production of AgNPs by the selected bacteria. Five independent variables were investigated through optimizations using one variable at a time (OVAT) and the Plackett-Burman experimental design (PBD). The overall optimal parameters for enhancing the biosynthesis of AgNPs using the supernatant of Leclercia adecarboxylata THHM as a novel organism were at an incubation time of 72.0 h, a concentration of 1.5 mM silver nitrate, a temperature of 40.0 °C, a pH of 7.0, and a supernatant concentration of 30% (v/v) under illumination conditions. The biosynthesized AgNPs have been characterized by UV-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The biosynthesized AgNPs showed an absorption peak at 423 nm, spherical shape, and an average particle size of 17.43 nm. FTIR shows the bands at 3321.50, 2160.15, and 1636.33 cm^-1 corresponding to the binding vibrations of amine, alkyne nitrile, and primary amine bands, respectively. The biosynthesized AgNPs showed antimicrobial activity against a variety of microbial pathogens of medical importance. Using resazurin-based microtiter dilution, the minimum inhibitory concentration (MIC) values for AgNPs were 500 µg/mL for all microbial pathogens except for Klebsiella pneumoniae ATCC13883, which has a higher MIC value of 1000 µg/mL.

CONCLUSIONS

The obtained data revealed the successful green production of AgNPs using the supernatant of Leclercia adecarboxylata THHM that can be effectively used as an antimicrobial agent against most human pathogenic microbes.

Phyto-Synthesis, Characterization, and In Vitro Antibacterial Activity of Silver Nanoparticles Using Various Plant Extracts

Aloe vera, Mentha arvensis (mint), Coriandrum sativum (coriander), and Cymbopogon citratus (lemongrass) leaf extracts were used to synthesize stable silver nanoparticles (Ag-NPs) by green chemistry. UV-vis spectrophotometry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy techniques were used to characterize these biosynthesized nanoparticles. The data indicated that the silver nanoparticles were successfully synthesized, and the narrower particle size distribution was at 10-22 nm by maintaining a specific pH. As a short-term post-sowing treatment, Ag-NP solutions of different sizes (10 and 50 ppm) were introduced to mung bean seedlings, and the overall increase in plant growth was found to be more pronounced at 50 ppm concentration. The antibacterial activity of Ag-NPs was also investigated by disc diffusion test, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) test. The zones of inhibition (ZOI) were shown by Escherichia coli (E. coli) (1.9, 2.1, 1.7, and 2 mm), followed by Staphylococcus aureus (S. aureus) (1.8, 1.7, 1.6, and 1.9 mm), against coriander, mint, Aloe vera, and lemongrass, respectively. MIC and MBC values of E. coli, and S. aureus ranged from 7 to 8 µg/mL. Overall, this study demonstrates that Ag-NPs exhibit a strong antimicrobial activity and thus might be developed as a new type of antimicrobial agent for the treatment of bacterial infection.

Effect of Phytosynthesized Selenium and Cerium Oxide Nanoparticles on Wheat (Triticum aestivum L.) against Stripe Rust Disease

In this study, selenium nanoparticles (SeNPs) and cerium oxide nanoparticles (CeONPs) were synthesized by using the extract of Melia azedarach leaves, and Acorus calamusas rhizomes, respectively, and investigated for the biological and sustainable control of yellow, or stripe rust, disease in wheat. The green synthesized NPs were characterized by UV-Visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The SeNPs and CeONPs, with different concentrations (i.e., 10, 20, 30, and 40 mg/L), were exogenously applied to wheat infected with Puccinia striformis. SeNPs and CeONPs, at a concentration of 30 mg/L, were found to be the most suitable concentrations, which reduced the disease severity and enhanced the morphological (plant height, root length, shoot length, leaf length, and ear length), physiological (chlorophyll and membrane stability index), biochemical (proline, phenolics and flavonoids) and antioxidant (SOD and POD) parameters. The antioxidant activity of SeNPs and CeONPs was also measured. For this purpose, different concentrations (50, 100, 150, 200 and 400 ppm) of both SeNPs and CeONPs were used. The concentration of 400 ppm most promoted the DPPH, ABTS and reducing power activity of both SeNPs and CeONPs. This study is considered the first biocompatible approach to evaluate the potential of green synthesized SeNPs and CeONPs to improve the health of yellow, or stripe rust, infected wheat plants and to provide an effective management strategy to inhibit the growth of Puccinia striformis.

Biological activities and antioxidant potential of different biosynthesized nanoparticles of Moringa oleifera

The science of nanotechnology is expanding daily and has the potential to benefit people. Moringa oleifera is an abundant source of phenolic compounds, which are bioactive substances. It is recognised as a necessary plant because of its medicinal potential and a wide variety of health benefits. The aim of the current study is to examine the antioxidant, antibacterial, and cytotoxicity effects of five nanoparticles (La₂O₃, CuO, Fe₂O₃, Ag, and ZnO) made using bioactive chemicals in the aqueous extract of Moringa oleifera leaves on four human cell lines (T47D, HepG2, A549, and Wi38). The UV-visible spectroscopy analysis with a surface plasmon peak in the 300-490 nm range and the value of the zeta potential of the various biosynthesized nanoparticles ranged from + 31 to + 37 mV, indicated the repulsion between the particles and the stability of the formulation nanoparticles confirmed the formation of all nanoparticles. Additionally, the DPPH method was used to assess the antioxidant activity of five distinct metal nanoparticles. The results show that this method works in parallel and is dependent on both the concentration of NPs and the incubation time. The anticancer effect of synthesized nanoparticles against four different cell lines has been tested. The cytotoxicity assay showed a dose-dependent and time-dependent effect of nanoparticles. The obtained results conclude that acceptable potency against T47D and A549 cell lines with IC₅₀ ranged from 38 to 210 μg/mL and 26 to 115 μg/mL, respectively. However, HepG2 and Wi38 cell lines showed relatively higher resistance against all tested nanoparticles when compared with Doxorubicin. Moreover, the antibacterial results revealed that silver nanoparticles exhibited the highest antibacterial activity against both Enterococcus faecalis and Staphylococcus aureus. Nanoparticles' high therapeutic activity at low concentrations opens up new avenues for the development of novel therapeutic approaches against human pathogens.

ZnO/CeO2 Nanocomposites: Metal-Organic Framework-Mediated Synthesis, Characterization, and Estimation of Cellular Toxicity toward Liver Cancer Cells

The Zinc-doped cerium oxide nanocomposite (ZnO/CeO₂ NC) was synthesized using a metal-organic framework as a precursor through the combustion method. It was characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), field emission electron microscopy (FESEM), energy dispersive analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), and ξ-potential. The PXRD demonstrated the successful synthesis of ZnO/CeO₂ NC with a crystallite size of 31.9 nm. FESEM and TEM images displayed hexagonal and spherical morphologies, and the solid-phase size was 65.03 ± 30.86 nm for ZnO/CeO₂ NCs. DLS, TEM, and FESEM showed that the NCs have a high tendency for agglomeration/aggregation in both aqueous media and solid phase. The anticancer attributes of ZnO/CeO₂ NC were investigated against Liver cancer cells (HepG2), which showed inhibition of cancer cell growth on a concentration-dependent gradient. The cell toxicity effects of ZnO/CeO₂ nanocomposites were also studied toward NIH-3T3, in which the data displayed the lower toxicity of NC compared to the HepG2 cell line.

Biosynthesis of silver nanoparticles using extracts of Stevia rebaudiana and evaluation of antibacterial activity

The present study reveals a simple, non-toxic and eco-friendly method for the "green" synthesis of Ag-NPs using hydroponic and soil medicinal plant Stevia rebaudiana extracts, the characterization of biosynthesized nanoparticles, as well as the evaluation of their antibacterial activity. Transmission electronic microscopy (TEM) and Dynamic Light Scattering (DLS) analysis confirmed that biosynthesized Ag-NPs are in the nano-size range (50-100 nm) and have irregular morphology. Biogenic NPs demonstrate antibacterial activity against Escherichia coli BW 25,113, Enterococcus hirae ATCC 9790, and Staphylococcus aureus MDC 5233. The results showed a more pronounced antibacterial effect on E. coli growth rate, in comparison with Gram-positive bacteria, which is linked to the differences in the structure of bacterial cell wall. Moreover, the Ag-NPs not only suppressed the growth of bacteria but also changed the energy-dependent H⁺-fluxes across the bacterial membrane. The change of H⁺-fluxes in presence of H⁺-translocating systems inhibitor, N,N'-dicyclohexylcarbodiimide (DCCD), proves the effect of Ag-NPs on the structure and permeability of the bacterial membrane. Overall, our findings indicate that the Ag-NPs synthesized by medicinal plant Stevia extracts may be an excellent candidate as an alternative to antibiotics against the tested bacteria.

Monitoring the effects of fungi isolated from archival document on model albumen silver prints

Fungi are a common problem in the photographic collection, so the aim of this study focused on isolating and molecular identification of fungi from old albumen prints dating to an archive of Dr. Francis and belonging to the Al-Hagar Family and dating back to 1880-1890. The isolated fungi were identified according to their morphological traits and PCR sequencing. The ability of these isolates to cause deterioration was evaluated on model samples (2 × 2 cm) of albumen silver prints. The effect of these fungi on the morphology and structure of the tested samples were examined by SEM, ATR-FTIR, and chromatic alternations. Four fungal species Aspergillus sydowii, A. flavus, Talaromyces atroroseus, and Penicillium chrysogenum were identified. All isolates were able to grow on the surface of the model Albumen silver print and were capable of causing damage to the binder and able to extend their growth to the paper fibers. A. sydowii, A. flavus, and P. chrysogenum caused hydrolysis and oxidation to the albumen prints, while no significant chemical damage to the albumen was detected for the photographic sample infected with T. atroroseus. All the inoculated samples were significantly affected in terms of color change and the high-light areas have become darker. ATR-FTIR spectra showed the degradation of the protein content in Albumen silver prints inoculated with A. sydowii, A. flavus, and P. chrysogenum.

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%.

MOF-Mediated Synthesis of CuO/CeO2 Composite Nanoparticles: Characterization and Estimation of the Cellular Toxicity against Breast Cancer Cell Line (MCF-7)

A copper oxide/cerium oxide nanocomposite (CuO/CeO₂, NC) was synthesized via a novel method using a metal–organic framework as a precursor. This nanomaterial was characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), dynamic light scattering size analysis (DLS), and zeta potential. The PXRD showed the successful synthesis of the CuO/CeO₂ NC, in which the 2theta values of 35.55° (d = 2.52 Å, 100%) and 38.73° (d = 2.32 Å, 96%) revealed the existence of copper (II) oxide. FTIR analysis showed the CeO₂, hydroxyl groups, absorbed water, and some residual peaks. The solid phase analysis by FESEM and TEM images showed mean particle sizes of 49.18 ± 24.50 nm and 30.58 ± 26.40 nm, respectively, which were comparable with crystallite size (38.4 nm) obtained from PXRD, but it appears the CuO/CeO₂ NC was not evenly distributed and in some areas, showed it was highly agglomerated. The hydrodynamic size (750.5 nm) also showed the agglomeration of the CuO/CeO₂ NCs in the solution, which had a negatively charged surface. The CuO/CeO₂ NCs showed anti-proliferative activity against human breast cancer cell line (MCF-7) in a dose- and time-dependence way, while affecting normal cells less significantly.