Biogenic Silver Nanoparticles Research Articles

Biogenic synthesis of silver nanoparticles using essential oil of aerial part of cyclospermum leptophyllum and their application in colorimetric determination of metallic ions

The focus of this research was to synthesize biogenic silver nanoparticles (AgNPs) using the essential oil of the aerial part of Cyclospermum leptophyllum (CLEO) and investigate their colorimetric determination of metallic ions. In the synthesis of CLEO mediated AgNPs (CLEO-AgNPs), the one-factor-at-a-time method was used to optimize the reaction parameters. Ultraviolet-visible (UV-Vis) peak of CLEO-AgNPs was determined at 426 nm. Fourier transform-infrared (FTIR) spectra analysis identified the functional groups participating in the bio-reducing, capping, and stabilizing processes in the CLEO-AgNPs synthesis. Scanning electron microscope (SEM) image demonstrated the predominately spherical shape and the average size of 70.86+1.80 nm of CLEO-AgNPs. Energy dispersive X-ray spectroscopy (EDX) peak profile depicted the presence of Ag elements in CLEO-AgNPs. The X-ray diffraction (XRD) peaks observed at 38.5°, 44°, 65°, and 77° which represent Ag(111), Ag(200), Ag(220), and Ag(311) lattice faces, respectively. The average zeta nanosize, zeta potential, and polydispersity index of CLEO-AgNPs were determined as 69.70 nm, -43.5 mV, and 0.256, respectively. The stability test exhibited the prolonged storage stability of CLEO-AgNPs for over six months at room temperature. CLEO-AgNPs demonstrated the potential colorimetric detection of K+, Mg2+, Al3+, Cr6+, Mn2+, Fe3+, Ni2+, Cu2+, Zn2+, Hg2+, Pb2+, and Cd2+ ions in the real samples.
 KEY WORDS: Cyclospermum leptophyllum, Essential oil, Biogenic silver nanoparticles, Bio-reductants, Colorimetric detection 
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 213-228. DOI: https://dx.doi.org/10.4314/bcse.v38i1.16

Silica supported biosynthesized silver nanoparticles as effective adsorbent and photocatalyst for removal of methylene blue from water

The silica supported silver nanoparticles (Ag@SG) were prepared by wet impregnation of silica gel (SG) using different concentrations of biogenic silver nanoparticles (AgNPs; 0.25–5 mM) solution, prepared from Cicer arientinum pod extract. Among them, the Ag@SG composite prepared by using 1.25 mM AgNPs solution (Ag1.25@SG) was found to contain only Ag0 species as nanoparticles, whereas the samples prepared by higher concentrations contained Ag0 as well as Ag+ (silver oxide) species. All the Ag@SG composites including SG, exhibited good adsorption capacity for a cationic dye (methylene blue; MB) in water. However, Ag1.25@SG having only Ag0 species exhibited higher photocatalytic activity for degradation of MB under visible light irradiation as compared to other composites. The study reveals that the plasmonic Ag0 species supported on silica are catalytically more active than Ag+ species. Furthermore, the AgNPs (Ag0) in supported form exhibits much higher (∼5-fold) photocatalytic activity than unsupported AgNPs. The synergistic effect of adsorption property of silica surface and plasmonic photocatalytic activity of AgNPs in the synthesized composites was found to be effective for the removal of MB. In addition, the fine dispersion of AgNPs on internal surface of silica provides better activity for photocatalysis. The study shows that this material is a promising adsorbent as well as photocatalyst for the removal of dyes from water.

Biopolymeric nanofibrous scaffolds of poly(3-hydroxybuthyrate)/chitosan loaded with biogenic silver nanoparticle synthesized using curcumin and their antibacterial activities

The increasing prevalence of multi-drug resistant bacteria poses a significant threat to public health, especially in wound infections. Developing new bactericidal agents and treatment strategies is crucial to address this issue. In this study, biopolymeric nanofibrous scaffolds containing green-synthesized silver nanoparticles (AgNPs) with curcumin (CUR) were evaluated as antimicrobial materials for wound healing therapy. Firstly, CUR was utilized to synthesize AgNPs, which were then analyzed using various analytical methods. The microstructural analysis revealed that the biogenic AgNPs, which had a spherical shape and an average size of 19.83 nm, were uniformly anchored on PHB/CTS nanofibers. Then, the AgNPs with various content (0.25–1%wt) were incorporated into PHB/CTS matrix to enhance its wettability, thermal and bactericidal behaviors. The nanofibrous scaffolds were characterized by FT-IR, FE-SEM, TGA analysis and water contact angle measurement. Overall, the addition of CUR-AgNPs to the PHB/CTS matrix led to a reduction in fiber diameter, enhanced hydrophilicity and improved thermal properties. Additionally, antibacterial activity against Staphylococcus aureus and Escherichia coli was performed on samples of AgNPS and PHB/CTS/CUR-Ag. The synthesized AgNPs showed antibacterial activity against both microorganisms, especially against S. aureus. Higher concentrations of AgNPs in nanofibers led to a significant reduction in bacterial colony formation. The results displayed that PHB/CTS/CUR-AgNPs nanofibrous scaffolds could be a promising material for the biomedical applications such as wound healing.

Biogenic Silver Nanoparticles and Stressors Generate Synergistic Growth Inhibition in Candida Species through Cell Wall Damage, Osmotic Stress, and Oxidative Stress.

The need to combat and reduce the incidence, virulence, and drug resistance of species belonging to Candida genus, has led to the development of new strategies. Nanotechnology, through the implementation of nanomaterials, has emerged as an infallible tool to treat various diseases caused by pathogens, where its mechanisms of action prevent the development of undesirable pharmacological resistance. The antifungal activity and adjuvant properties of biogenic silver nanoparticles in different Candida species (C. parapsilosis, C. glabrata, and C. albicans) are evaluated. The biogenic metallic nanoparticles were developed by quercetin-mediated biological synthesis. The physicochemical properties were studied by light scattering, electrophoretic mobility, UV-vis and infrared spectroscopy, and transmission electron microscopy. The elucidation of mechanisms of antifungal action was carried out under stress conditions in Candida species at the cell wall and response to oxidative stress. Small silver nanoparticles (≈ 16.18 nm) with irregular morphology, and negative surface electrical charge (≈ -48.99 mV), were obtained through quercetin-mediated biosynthesis. Infrared spectra showed that the surface of silver nanoparticles is functionalized with the quercetin molecule. The antifungal activity of biogenic nanoparticles had efficacy in the following trend C. glabrata ≥ C. parapsilosis > C. albicans. Biogenic nanoparticles and stressors showed synergistic and potentiated antifungal effects through cell damage, osmotic stress, cell wall damage, and oxidative stress. Silver nanoparticles synthesized by quercetin-mediated biosynthesis could be implemented as a powerful adjuvant agent to enhance the inhibition effects of diverse compounds over different Candida species.

Abstract 23 — Ameliorative Effect of Biogenic Silver Nanoparticles Mediated with Naringin Against Collagen Induced Rheumatoid Arthritis in Rodents by Acting on Inflammation and Gut Microbiota

Background Rheumatoid arthritis (RA) hallmarked by functional impairment in joints due to inflammation, destruction and erosion of cartilages and bones. RA accounts as a major healthcare burden globally, hence there is a requirement of a novel therapeutic approach. Naringin is a flavanone glycoside possessing a variety of pharmacological activities in addition to anti-inflammatory and antioxidant properties. Among various metal oxide nanoparticles, silver nanoparticle drawing the attention of researchers as it possesses anti-inflammatory activity and utilized widely as a delivery vehicle for various natural anti-inflammatory drugs against RA. The study was designed to explore the effect of biogenic silver nanoparticles mediated with naringin (NAgNP) against RA induced by type II collagen, inflammation and gut microbiota in wistar rats. Methods NAgNPs were synthesized by co-precipitation method and characterized by various characterization techniques. Rats were employed for the study and randomized into five groups. Except control group, each group was treated with bovine type-II collagen (intradermal injection, 100 [Formula: see text] g) suspended in Freund’s complete adjuvant. On day 21 of the study, bovine type-II collagen and booster incomplete Freund’s adjuvant were again provided. Vehicle (Con), Methotrexate (Std, 3 mg/kg) and Test drugs, i.e., NAgNP, at three different dose levels (2, 4 and 8 mg/kg) were given in respective groups for consecutive 21 days. On the last day of study, various biochemical parameters including pro-inflammatory cytokine level in serum and the status of gut microbiome population were assessed with Illumina HiSeq. Results Characterization techniques confirmed the formation of spherical NAgNP with a size range of 80-100 nm. Data revealed that the groups administered with NAgNP exhibited a statistically significant decrease in (p < 0.01) rat paw swelling as well as arthritis scores than the control group. Different inflammatory markers such as IL-1[Formula: see text], IL-6, IL-7 and TNF-[Formula: see text] were found to be significantly reduced as compared to the control group. Significant improvement in the gut microbial population by alleviating the relative level of various microbes associated with inflammation was also observed. Conclusion NAgNP can be utilized as a beneficial candidate in the management of RA by the mechanism of amelioration of inflammation and gut microbiota.

Evaluation of Biogenic Silver Nanoparticles Synthesized from Vegetable Waste

Evaluation of Biogenic Silver Nanoparticles Synthesized from Vegetable Waste

Silk fibroin-based green colloidal silver nanoparticle synthesis and their antibacterial and anticancer properties

Aqueous silk fibroin (SF), derived from Bombyx mori silk, was used to synthesize colloidal silver nanoparticles (AgNPs) in situ under white light and at ambient temperature. A characteristic surface plasmon resonance (SPR) band at 425–435 nm from the UV–Vis spectrum provided evidence of the formation of AgNPs by UV–Visible spectroscopy. The nanoparticles that were synthesized were spherical with smooth surfaces, as evidenced by the transmission electron microscope (TEM) photographs. The size of the particles was between 35 and 40 nm. Additionally, X-ray diffraction (XRD) investigation supports the existence of silver's nanocrystalline phase with FCC crystal structure. The human bacterial pathogens Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) were significantly inhibited by the biogenic silver nanoparticles' antibacterial activity. The synthesized nanoparticles also show an excellent anti-cancer activity in lowest dosage.

Dentin bond strength and antimicrobial activities of universal adhesives containing silver nanoparticles synthesized with Rosa canina extract.

The purpose in the study was to evaluate the effect of biogenic silver nanoparticles (Ag NPs) synthesized by the green synthesis method on dentin bond strength in three different universal adhesives and investigate their antibiofilm activity against Streptococcus mutans (S. mutans). Three different universal adhesives (single bond universal, all-bond universal, and clearfil universal) were used in this study. Ag NPs were synthesized using rose hip (Rosa canina) extract as a reducing and stabilizing agent and they were characterized with STEM, UV-vis spectrophotometer, DLS, and zeta potential. Ag NPs were added to the adhesive resins at a rate of 0.05% (w/w), and their homogeneous distribution in the adhesive was determined using EDX spectrometry. Samples in all groups were tested at baseline-after 5000 and 10,000 thermal cycles. Adhesive composite discs were used for the live/dead analysis of S. mutans, MTT metabolic activity test, lactic acid production, and determination of colony-forming unit (CFU) values (n = 3). Ninety extracted caries-free human third molars were used to determine microtensile bond strength (μTBS) (n = 10). After the universal adhesive was applied to the dentin surface, composite resin (Z550 XT, 3M ESPE, USA) was placed and sections were taken to form a composite-dentin stick of 1mm × 1mm wideness and 8-mm length. The sticks were broken at a rate of 1mm/min under uniaxial tension in a universal testing machine, and the failure modes were determined by SEM. One-way analysis of variance (ANOVA) for antibacterial tests and two-way analysis of variance for μTBS tests were performed (p < 0.05). All universal adhesive groups containing Ag NPs showed higher antibacterial activity than control groups without Ag NPs (p < 0.05). There was a statistically significant difference in the live/dead assay analysis, MTT metabolic activity test, lactic acid production, and CFU values in the thermal cycled Ag NPs groups (p < 0.05). Antibacterial activity decreased in groups containing Ag NPs subjected to 10,000 thermal cycles. The highest lactic acid production 11.06 (± 0.629) and CFUs 7.61 (± 0.304), live bacteria 31.13 (± 0.466), and S. mutans MTT metabolic activity 0.29 (± 0.376) at AU (All-Bond Universal-Ag NPs) 10,000 thermal cycles group. There was no difference in μTBS values between the initial and 5000 thermal cycle groups, there was a difference between the 10,000 thermal cycle groups. The CU (Clearfil Universal-Ag NPs) group subjected to 10,000 thermal cycles showed lower μTBS 11.1 (± 3.2). In conclusion, universal adhesives containing biogenic Ag NPs showed higher antibacterial activity than the control groups and did not reduce the μTBS. Antibacterial universal adhesives can contribute to restoration success in clinical applications by reducing residual bacteria and preventing secondary caries formation.

Biogenic Silver and Copper Nanoparticles: Potential Antifungal Agents in Rice and Wheat Crops

Metal nanoparticles are widely studied due to their various applications, such as their potential use in the control of phytopathogens and the promotion of plant growth, with a significant impact on agriculture. Various microbial metabolites are used to reduce and stabilize metals and metal oxides to the nanoscale. In the present work, the biological synthesis of silver and copper oxide nanoparticles using Trichoderma harzianum TA2 is reported. The nanoparticles were purified and characterized with complementary methodologies to obtain information on the size, distribution, morphology, surface charge, and functional groups of the nanoparticles. The in vitro antifungal activity of the nanoparticles against pathogens of rice and wheat, as well as their effect on seed germination, were evaluated. In general, the nanoparticles showed a spherical shape, an average size of 17–26 nm, and low polydispersity. Furthermore, they showed antifungal activity at low concentrations against Sclerotium oryzae (0.140 ηM), Rhizoctonia oryzae-sativae (0.140 ηM), Fusarium graminearum (0.034 ηM), and Pyricularia oryzae (0.034 ηM). The germination of seeds treated with nanoparticles was not negatively affected. This is the first report of biogenic silver and copper oxide nanoparticles from a single strain of T.harzianum with antifungal activity against four phytopathogens of interest in Uruguay. Furthermore, the synthesis of the biogenic nanoparticles was faster and more efficient than previous reports using other fungi. In conclusion, this work reveals that biogenic metallic nanoparticles from T. harzianum TA2 can be considered as candidates for the control of phytopathogens affecting important crops.

Use of biogenic silver nanoparticles on the cathode to improve bioelectricity production in microbial fuel cells.

To date, research on microbial fuel cells (MFCs) has. focused on the production of cost-effective, high-performance electrodes and catalysts. The present study focuses on the synthesis of silver nanoparticles (AgNPs) by Pseudomonas sp. and evaluates their role as an oxygen reduction reaction (ORR) catalyst in an MFC. Biogenic AgNPs were synthesized from Pseudomonas aeruginosa via facile hydrothermal synthesis. The physiochemical characterization of the biogenic AgNPs was conducted via scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible spectrum analysis. SEM micrographs showed a spherical cluster of AgNPs of 20-100nm in size. The oxygen reduction reaction (ORR) ability of the biogenic AgNPs was studied using cyclic voltammetry (CV). The oxygen reduction peaks were observed at 0.43V, 0.42V, 0.410V, and 0.39V. Different concentrations of biogenic AgNPs (0.25-1.0mg/cm2) were used as ORR catalysts at the cathode in the MFC. A steady increase in the power production was observed with increasing concentrations of biogenic AgNPs. Biogenic AgNPs loaded with 1.0mg/cm2 exhibited the highest power density (PDmax) of 4.70W/m3, which was approximately 26.30% higher than the PDmax of the sample loaded with 0.25mg/cm2. The highest COD removal and Coulombic efficiency (CE) were also observed in biogenic AgNPs loaded with 1.0mg/cm2 (83.8% and 11.7%, respectively). However, the opposite trend was observed in the internal resistance of the MFC. The lowest internal resistance was observed in a 1.0mg/cm2 loading (87Ω), which is attributed to the high oxygen reduction kinetics at the surface of the cathode by the biogenic AgNPs. The results of this study conclude that biogenic AgNPs are a cost-effective, high-performance ORR catalyst in MFCs.

Broad-spectrum antibacterial and antibiofilm activity of biogenic silver nanoparticles synthesized from leaf extract of Phyllanthus niruri

Multidrug resistance (MDR) among pathogenic bacteria is a global health concern as it has rendered the current antibiotic therapy ineffective. A recent and rapidly developing research area in the biomedical sector is the use of biogenic nanoparticles as antibacterial agents. In the current investigation, aqueous leaf extract of Phyllanthus niruri (Pn-AgNPs) were employed for the biogenic synthesis of silver nanoparticles, further characterized by SEM, EDX, FTIR, TEM, UV–Vis and XRD techniques. Electron microscopy images of the green-synthesized Pn-AgNPs showed them as evenly dispersed spherical particles having an average size of about ∼ 20 nm. The Pn-AgNPs were further tested for potential antibacterial activity against isolated drug-resistant pathogenic bacteria such as Burkholderia cepacia complex, carbapenem-resistant Enterobacterales (CRE), Citrobacter freundii, Enterococcus faecalis, Escherichia coli, Enterobacter clocae, MRSA, Salmonella typhi, Streptococcus spp, and vancomycin-resistant Enterococci (VRE).The Pn-AgNPs significantly inhibited growth all of the studied bacterial isolates, including antibiotic-resistant isolates such as MRSA, VRE, and CRE. Electron micrographs clearly showed the enhanced penetration of AgNPs leading to disruption of cell membrane causing death of the cell. Further, Pn-AgNPs dramatically reduced the ability of P. aeruginosa, Bacillus cereus, E. coli, and S. aureus to form biofilms. Leakage of protein from bacterial cells could be main reason for the effective bactericidal action of synthesized AgNPs. This antibacterial and antibiofilm potential of Phyllanthus niruri biosynthesized AgNPs against clinically significant drug-resistant bacteria is impressive and can be developed as a novel antimicrobial agent to combat the threat of drug-resistant bacterial infections.

Long-Term Impact of Surfactants on Colloidal Stability and Antibacterial Properties of Biogenic Silver Nanoparticle

Long-Term Impact of Surfactants on Colloidal Stability and Antibacterial Properties of Biogenic Silver Nanoparticle

Biogenic silver nanoparticles: in vitro activity against Staphylococcus aureus methicillin-resistant (MRSA) and multidrug-resistant coagulase-negative Staphylococcus (CoNS).

Multidrug-resistant (MDR) bacteria are one problem in health since the therapeutic alternative are reduced. For this, the application of nanotechnology through functionalized nanoparticles, like a biogenic silver nanoparticle (Bio-AgNP), obtained by biological synthesis, emerges as a possible alternative against the MDR bacteria. This study aimed to evaluate the antibacterialand antibiofilm activity of Bio-AgNP obtained for biological synthesis by Fusarium oxysporum strain 551 against methicillin-resistant Staphylococcus aureus (MRSA) and MDR coagulase-negative Staphylococcus (CoNS) isolates. Bio-AgNP has activity against S. aureus ATCC 25904, Staphylococcus epidermidis ATCC 35984, and MDR isolates, with minimal inhibitory concentration (MIC) ranging from 3.75 to 15 μg.mL-1 and minimal bactericidal concentration (MBC) from 7.5 to 30 μg.mL-1. In the membrane leakage assay, it was observed that all concentrations tested led to proteins release from the cellular content dose-dependently, where the highest concentrations led to higher protein in the supernatant. The 2×MIC of Bio-AgNP killed ATCC 35984 after 6h of treatment, and ATCC 25904 and S. aureus (SA3) strains after 24h of treatment. The 4×MIC was bactericidal in 6h of treatment for all strains in the study. The biofilm of MDR isolates was inhibited in 80.94 to 100% and eradicated in 60 to 94%. The confocal laser scanning microscopy (CLSM) analysis demonstrated similar results to the antibiofilm assays. The Bio-AgNP has antibacterial and antibiofilm activity and can be a promising therapeutic alternative against MDR bacteria.

Structural characterization, antioxidant and anti-uropathogenic potential of biogenic silver nanoparticles using brown seaweed Turbinaria ornata.

Alternative treatment strategies for urinary tract infections (UTIs) are becoming more necessary due to increasing drug resistance patterns in uropathogens. Nanoparticle-based therapeutics is emerging as a way to treat UTIs. In the present study, using Turbinaria ornata extract, silver nanoparticles (AgNPs) were synthesized, characterized, and their anti-uropathogenic activity was evaluated. The stability and formation of synthesized To-AgNPs were confirmed by UV-visible spectroscopy, FTIR, XRD, SEM, and DLS. An FTIR spectrum confirmed the presence of seaweed functional groups in To-AgNPs, a XRD analysis confirmed their crystalline nature, and SEM imaging confirmed their spherical nature with an average size of 73.98 nm with diameters ranging from 64.67 to 81.28 nm. This was confirmed by TEM results. DLS determined that the cumulant hydrodynamic diameter of To-AgNPs was 128.3 nm with a PdI of 0.313 and the zeta potential value were found to be -63.3 mV which indicates the To-AgNPs are negatively charged and more stable. DPPH assays were used to assess the antioxidant activity of biosynthesized To-AgNPs, while an agar well diffusion method was used to test the antibacterial activity against uropathogens, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Klebsiella pneumoniae. The To-AgNPs showed the highest susceptibility to S. aureus (15.75 ± 0.35 mm) and E. coli (15 ± 0.7 mm) with MIC values of 0.0625 and 0.125 mg/ml, respectively in macro broth dilution method and observed considerable membrane damage under CLSM and SEM. To-AgNPs displayed stronger antioxidant and antimicrobial activity, suggesting they may be developed as a new class of antimicrobial agents for treating UTIs.

Green synthesis of nano-silver and its antibacterial activity against methicillin-resistant Staphylococcus aureus

Superbugs resistant to antimicrobials are swiftly expanding worldwide. One of these superbugs for which effective antibiotics are urgently needed is methicillin-resistant Staphylococcus aureus (MRSA). Thus, the creation of novel antimicrobial substances is necessary, one of the appealing antibacterial inorganic materials is silver nanoparticles (AgNPs) for application of treating bacterial infectious illnesses. In order to investigate novel, potent, and economically feasible therapeutic approaches, the current study presents a cost-effective and environmentally friendly technique for synthesizing AgNPs using Citrus maxima peel (CMP) extract as a reducing agent. UV–Vis Spectroscopy confirmed the formation of AgNPs in the 400–––500 nm wavelength range. The Powder X-ray diffr action (PXRD) and high-resolution transmission electron microscopy (HRTEM) results at the optimized synthesis conditions revealed highly crystalline AgNPs (face-centered cubic structure) with particles the size of 10–––20 nm. The Fourier transform infrared spectroscopy (FT-IR) revealed the presence of flavonoids, terpenoids, phenolics, and glycosides in the phytochemical compositions of the CMP extract, which can serve as reducing agents for the formation of the spherical AgNPs. Minimum inhibitory concentration (MIC) values of 8.27 µg/mL, minimum bactericidal concentration (MBC) values of 16.54 µg/mL, and an inhibition zone of 11.7 mm were indicative of the potent antibacterial activity of as-prepared AgNPs against MRSA. The findings suggest biogenic silver nanoparticles could be an effective antimicrobial agent against nosocomial infections.

Biogenic Nanoparticles Silver and Copper and Their Composites Derived from Marine Alga Ulva lactuca: Insight into the Characterizations, Antibacterial Activity, and Anti-Biofilm Formation.

Bacterial pathogens cause pain and death, add significantly to the expense of healthcare globally, and pose a serious concern in many aspects of daily life. Additionally, they raise significant issues in other industries, including pharmaceuticals, clothing, and food packaging. Due to their unique properties, a great deal of attention has been given to biogenic metal nanoparticles, nanocomposites, and their applications against pathogenic bacteria. This study is focused on biogenic silver and copper nanoparticles and their composites (UL/Ag2 O-NPS, Ul/CuO-NPs, and Ul/Ag/Cu-NCMs) produced by the marine green alga Ulva lactuca. The characterization of biogenic nanoparticles UL/Ag2 O-NPS and Ul/CuO-NPs and their composites Ul/Ag/Cu-NCMs has been accomplished by FT-IR, SEM, TEM, EDS, XRD, and the zeta potential. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) experiments were conducted to prove antibacterial activity against both Gram-positive and Gram-negative bacteria and anti-biofilm. The FTIR spectroscopy results indicate the exiting band at 1633 cm-1, which represents N-H stretching in nanocomposites, with a small shift in both copper and silver nanoparticles, which is responsible for the bio-reduction of nanoparticles. The TEM image reveals that the Ul/Ag/Cu-NCMs were hexagonal, and the size distribution ranged from 10 to 35 nm. Meanwhile, Ul/CuO-NPs are rod-shaped, whereas UL/Ag2 O-NPS are spherical. The EDX analysis shows that Cu metal was present in a high weight percentage over Ag in the case of bio-Ag/Cu-NCMs. The X-ray diffraction denotes that Ul/Ag/Cu-NCMs, UL/CuO-NPs, and UL/Ag2 O-NPS were crystalline. The results predicted by the zeta potential demonstrate that Ul/Ag/Cu-NCMs were more stable than Ul/CuO-NPs. The antibacterial activity of UL/Ag2 O-NPS, Ul/Ag/Cu-NCMs, and UL/CuO-NPs was studied against eleven Gram-negative and Gram-positive multidrug-resistant bacterial species. The maximum inhibition zones were obtained with UL/Ag2 O-NPS, followed by Ul/Ag/Cu-NCMs and Ul/CuO-NPs in all the tested bacteria. The maximum anti-biofilm percentage formed by E. coli KY856933 was obtained with UL/Ag2 O-NPS. These findings suggest that the synthesized nanoparticles might be a great alternative for use as an antibacterial agent against different multidrug-resistant bacterial strains.

Alginate coated biogenic silver nanoparticles for the treatment of Pseudomonas infections in rainbow trout

Pseudomonas species are among the main pathogens causing rainbow trout infections. The present study provides a simple, green, sustainable, and rapid technique to synthesize of biogenic alginate-capped silver nanoparticles (Alg-Ag NPs) suitable for the treatment of Pseudomonas infections. It has been shown that the mechanism (aggregative or autocatalytic) of Alg-Ag NPs formation depended on Alg concentration and the heating approach used. The rate constants and activation energy were calculated. Alg-Ag NPs were characterized by UV–Vis, FTIR, XRD, TEM, AFM, XPS, and DLS. The optimal conditions for the fabrication of spherically-shaped (17–19 nm) and negatively-charged (zeta-potential <−50 mV) Alg-Ag NPs, which are stable during 9 months, included hot-plate assisted synthesis at 100 °C in diluted (1 mg/mL) Alg solutions. In vitro studies showed that Alg-Ag NPs exhibited prominent antimicrobial activity against collection Pseudomonas strains (inhibition zones ranged from 9.0 ± 1.0 to 19.0 ± 1.0 mm), with no significant loss of antibacterial efficacy after 9 months of storage. AFM analysis confirmed that the antibacterial effect of Alg-Ag NPs dealt with the direct nanomechanical disrupting of bacterial cells. The ability of Alg-Ag NPs to inhibit the growth of virulent P.aeruginosa, P.fluorescens and P. putida strains isolated from infected rainbow trout was evaluated. All tested strains were susceptible to Alg(10)-Ag NPs, while Alg(1)-Ag NPs demonstrated a limited strain-specific antibacterial effect. The obtained data displayed the prospects for the application of biogenic Alg-Ag NPs to create novel delivery systems for combating Pseudomonas infections in rainbow trout.

Biogenic Silver Nanoparticles for Targeted Cancer Therapy and Enhancing Photodynamic Therapy.

Different conventional therapeutic procedures are utilized globally to manage cancer cases, yet the mortality rate in patients with cancer remains considerably high. Developments in the field of nanotechnology have included novel therapeutic strategies to deal with cancer. Biogenic (green) metallic silver nanoparticles (AgNPs) obtained using plant-mediated protocols are attractive to researchers exploring cancer treatment. Biogenic AgNPs present advantages, since they are cost-effective, easy to obtain, energy efficient, and less toxic compared to chemically and physically obtained AgNPs. Also, they present excellent anticancer abilities thanks to their unique sizes, shapes, and optical properties. This review provides recent advancements in exploring biogenic AgNPs as a drug or agent for cancer treatment. Thus, great attention was paid to the anticancer efficacy of biogenic AgNPs, their anticancer mechanisms, their efficacy in cancer photodynamic therapy (PDT), their efficacy in targeted cancer therapy, and their toxicity.

In-vitro anticancer and antibacterial activities and comparative of eco-friendly synthesized silver nanoparticles using hull of Pistacia vera and rhizome of Sambucus ebulus extracts

The biogenic method of synthesizing nanoparticles offers an effective alternative to traditional chemical synthesis systems. Additionally, the rapid development of eco-friendly techniques for producing metallic nanoparticles is driven by their extensive applications in various scientific fields. The present study investigated the production of silver nanoparticles (AgNPs) using hull of Pistacia vera (PV-AgNPs) and rhizomes of Sambucus ebulus (SE-AgNPs) extracts. The eco-friendly synthesis of Ag nanoparticles was carried out by optimizing three physicochemical parameters, including silver salt concentration, temperature, and pH. Biogenic silver nanoparticles were characterized using several analytical techniques, including FESEM, EDS, XRD, TEM and UV-Vis. The average sizes of PV-AgNPs and SE-AgNPs were determined to be 19.32 nm and 15.63 nm, respectively, using X-ray diffraction patterns. These findings were consistent with the results obtained from scanning electron microscopy. The antibacterial efficacy of AgNPs was evaluated against both Gram-negative and Gram-positive pathogens. AgNPs exhibited the highest antibacterial activity against S. aureus and E. faecalis, with a minimum inhibitory concentration (MIC) value of 12.5 µg/ml for PV-AgNPs. Additionally, for SE-AgNPs, the MIC value against S. aureus was found to be 2 µg/ml, indicating a potent antibacterial effect. Moreover, the anticancer potential of AgNPs was assessed using the MTT assay on MCF-7 (breast cancer) and AGS (human gastric carcinoma) cell lines as representative cancer cell models. The IC50 value of SE-AgNPs on MCF-7 and AGS was found to be 24.3 and 32.5 μg/ml, respectively. Hence, the present study indicates that biologically synthesized AgNPs have significant potential for exploitation in various biological applications.

First report of Pythium aphanidermatum infecting tomato in Egypt and its control using biogenic silver nanoparticles

First report of Pythium aphanidermatum infecting tomato in Egypt and its control using biogenic silver nanoparticles