Antimicrobial activity of chemically and biologically synthesized silver nanoparticles against some fish pathogens

Pathogens isolated from fish appear to possess considerable antimicrobial resistance and represent a problem for the economy and public health. Natural antimicrobial substitutes to traditional antibiotics represent an essential tool in the fight against antibiotic resistance. Nanotechnology has shown considerable potential in different research fields, and the antimicrobial properties of silver nanoparticles are known. Silver has been used for medical purposes since ancient times because of its bactericidal properties, and the highly reactive surfaces of silver nanoparticles (AgNPs) indicate that they might have a function in antimicrobial applications. This work aimed to study the antimicrobial properties of biologically produced AgNPs from Origanum vulgare leaves compared to chemically produced AgNPs. Both types were characterized by UV–vis spectrophotometry, TEM, and dynamic light scattering and tested against three bacterial strains (Streptococcus agalactiae, and Aeromonas hydrophila, both isolated from Nile tilapia and Vibrio alginolyticus, isolated from sea bass) and three fungal strains (Aspergillus flavus, Fusarium moniliforme, and Candida albicans, all isolated from Nile tilapia). Disk diffusion test and evaluation of ultrastructure changes of tested microorganisms treated with AgNPs by transmission electron microscopy were performed. Moreover, the hemolytic properties of AgNPs were studied on chicken and goat red blood cells. The results obtained declare that the green biological production of silver nanoparticles is safer and more effective than the chemical one; moreover, AgNPs have interesting dose-dependent antimicrobial properties, with better results for biologically produced ones; their effectiveness against tested bacterial and fungal strains opens the way to their use to limit fish diseases, increase economy and improve human health.     

Comparison of Antimicrobial Properties of Silver Nanoparticles Synthesized from Selected Bacteria

Green silver nanoparticle (AgNP) biosynthesis is facilitated by the enzyme mediated reduction of Ag ions by plants, fungi and bacteria. The antimicrobial activity of green AgNPs is useful to overcome the challenge of antimicrobial resistance. Antimicrobial properties of biosynthesized AgNPs depend on multiple factors including culture conditions and the microbial source. The antimicrobial activity of AgNPs biosynthesized by Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Acinetobacter baumannii (confirmed clinical isolate) were investigated in this study. Biosynthesis conditions (AgNO₃ concentration, pH, incubation temperature and incubation time) were optimized to obtain the maximum AgNP yield. Presence of AgNPs was confirmed by observing a characteristic UV–Visible absorbance peak in 420–435 nm range. AgNP biosynthesis was optimal at 0.4 g/L AgNO₃ concentration under alkaline conditions at 60–70 °C. The biosynthesized AgNPs showed higher stability compared to chemogenized AgNPs in the presence of electrolytes. AgNPs synthesized by P. aeruginosa were the most stable while NPs of S. aureus were the least stable. AgNPs synthesized by P. aeruginosa and S. aureus showed good antimicrobial potential against E. coli, P. aeruginosa, S. aureus, MRSA and Candida albicans. AgNPs synthesized by S. aureus had greater antimicrobial activity. The antimicrobial activity of NPs may vary depending on the size and the morphology of NPs.     

Prospective of biosynthesized L.satiVum oil/PEG/Ag-MgO bionanocomposite film for its antibacterial and anticancer potential

A substantial interest has been manifested in utilizing oil/metal oxide hybrid bionanocomposite, especially organic/ inorganic to design different biomedical applications. The present study reports the synthesis, characterization, antibacterial and anticancer properties of biogenic silver nanoparticles (AgNPs) and L.satiVum oil/PEG/Ag-MgO bionanocomposite. The fabricated AgNPs and L.sativum oil/PEG/Ag-MgO bionanocomposite were characterized by employing different spectroscopic (UV, FTIR, XRD) and microscopic (TEM, SEM) techniques. The particle size analysis showed that the mean size of 16.32 nm for AgNPS and 13.45 nm L.satiVum oil/PEG/Ag-MgO, indicating the excellent dispersion of Ag-MgO nanoparticles in the PEG– L.satiVum oil matrix. The antimicrobial activity of AgNPs and polymeric bionanocomposite was investigated against two pathogenic bacteria. The highest antibacterial effect was observed for bionanocomposite towards Gram-positive Staphylococcus aureus (27 mm) and Gram-negative Escherichia coli (25 mm) at 40 µg/well. The bionanocomposite completely vanished the bacterial growth (100%) at 80 µgmL⁻¹ concentrations. Moreover, the AgNPs and polymeric bionanocomposite was evaluated for anticancer activity against human cervical cancer cells (HeLa cells) at different doses (50, 250, 500, and 1000 µgmL⁻¹). The results showed polymeric bionanocomposite was stronger in inducing the HeLa cancer cell death than AgNPs. Overall, the fabricated L.satiVum oil/PEG/Ag-MgO bionanocomposite serve as a potential antimicrobial and anticancer agent and could be used in the development of novel drugs and health care products in near future.     

Evaluation of the antimicrobial potency of silver nanoparticles biosynthesized by using an endophytic fungus,Cryptosporiopsis ericae PS4

In the present study, silver nanoparticles (AgNPs) with an average particle size of 5.5 ± 3.1 nm were biosynthesized using an endophytic fungus Cryptosporiopsis ericae PS4 isolated from the ethno-medicinal plant Potentilla fulgens L. The nanoparticles were characterized using UV-visible spectrophotometer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), selective area electron diffraction (SAED), and energy dispersive X-ray (EDX) spectroscopy analysis. Antimicrobial efficacy of the AgNPs was analyzed singly and in combination with the antibiotic/antifungal agent chloramphenicol/fluconazole, against five pathogenic microorganisms-Staphylococcus aureus MTCC96, Salmonella enteric MTCC735, Escherichia coli MTCC730, Enterococcus faecalis MTCC2729, and Candida albicans MTCC 183. The activity of AgNPs on the growth and morphology of the microorganisms was studied in solid and liquid growth media employing various susceptibility assays. These studies demonstrated that concentrations of AgNPs alone between 10 and 25 μM reduced the growth rates of the tested bacteria and fungus and revealed bactericidal/fungicidal activity of the AgNPs by delaying the exponential and stationary phases. Examination using SEM showed pits and ruptures in bacterial cells indicating fragmented cell membrane and severe cell damage in those cultures treated with AgNPs. These experimental findings suggest that the biosynthesized AgNPs may be a potential antimicrobial agent.     

Comparative study of antifungal activity of two preparations of green silver nanoparticles from Portulaca oleracea extract

The green silver nanoparticles (green AgNPs) exhibit an exceptional antimicrobial property against different microbes, including bacteria and fungi. The current study aimed to compare the antifungal activities of both the crude aqueous extract of Portulaca oleracea or different preparations of green AgNPs biosynthesized by mixing that aqueous extract with silver nitrate (AgNO₃). Two preparations of the green AgNPs were synthesized either by mixing the aqueous extract of P. oleracea with silver nitrate (AgNO₃) (normal AgNPs) or either irradiation of the AgNPs, previously prepared, under ⁶⁰Co γ-ray using chitosan (gamma-irradiated AgNPs). Characterization of different AgNPs were tested by Zeta potential analyzer, Ultraviolet (UV) Visible Spectroscopy, and Fourier-Transform Infrared (FTIR) spectrometry. Three different plant pathogenic fungi were tested, Curvularia spicifera, Macrophomina phaseolina, and Bipolaris sp. The antifungal activities were evaluated by Transmission Electron Microscope (TEM) for either the crude aqueous extract of P. oleracea at three doses (25%, 50%, and 100%) or the newly biosynthesized AgNPs, normal or gamma-irradiated. With a few exceptions, the comparative analysis revealed that the irradiated green AgNPs at all three concentrations showed a relatively stronger antifungal effect than the normal AgNPs against all the three selected fungal strains. UV–visible spectroscopy of both preparations showed surface plasmon resonance at 421 nm. TEM results showed that both AgNPs were aggregated and characterized by a unique spherical shape, however, the gamma-irradiated AgNPs were smaller than the non-irradiated AgNPs (0.007–0.026 µM vs. 0.009–0.086 µM). TEM photographs of the fungal strains treated with the two AgNPs preparations showed flaccid structures, condensed hyphae, and shrunken surface compared with control cells. The data suggested that the biosynthesized P. oleracea AgNPs have antifungal properties against C. spicifera, M. phaseolina, and Bipolaris sp. These AgNPs may be considered a fungicide to protect different plants against phytopathogenic fungi.     

Green synthesis of silver nanoparticles using Citrus limon peels and evaluation of their antibacterial and cytotoxic properties

The present work aimed to synthesis silver nanoparticles (AgNPs) using biological waste products Citrus limon peels, its characterization, antimicrobial activities and the cytotoxic effect of the synthesized green AgNPs. Characterization of the prepared AgNPs showed the formation of spherical, and few agglomerated AgNPs forms as measured by UV–visible spectrophotometer. The average size of the prepared AgNPs was 59.74 nm as measured by DLS technique. The spectrum of the synthesized AgNPs was observed at 3 KeV using the EDX. On the other hand, FTIR analysis of the green synthesized AgNPs showed the presence of alcohols, phenolics, mono-substituted alkynes, aliphatic primary amines, sodium salt, amino acid, or SiOH alcohol groups. The antimicrobial studies of the formed AgNPs showed positive activity against most of the studied human pathogenic bacteria with varying degrees. Finally, the evaluation of the cytotoxic effect of the green synthesized AgNPs were done using two types of cell lines, human breast cancer cell line (MCF-7) and human colon carcinoma cell line (HCT-116). The results revealed the concentration has a direct correlation with cell viability. The 50% inhibitory concentration (IC₅₀) of MCF-7 cell line was in of 23.5 ± 0.97 µL/100 µL, whereas the HCT-116 cell line was in 37.48 ± 5.93 µL/100 µL.     

A combination of silver nanoparticles and visible blue light enhances the antibacterial efficacy of ineffective antibiotics against methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA)

Background

Silver nanoparticles (AgNPs) are potential antimicrobials agents, which can be considered as an alternative to antibiotics for the treatment of infections caused by multi-drug resistant bacteria. The antimicrobial effects of double and triple combinations of AgNPs, visible blue light, and the conventional antibiotics amoxicillin, azithromycin, clarithromycin, linezolid, and vancomycin, against ten clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) were investigated.

Methods

The antimicrobial activity of AgNPs, applied in combination with blue light, against selected isolates of MRSA was investigated at 1/2–1/128 of its minimal inhibitory concentration (MIC) in 24-well plates. The wells were exposed to blue light source at 460 nm and 250 mW for 1 h using a photon emitting diode. Samples were taken at different time intervals, and viable bacterial counts were determined. The double combinations of AgNPs and each of the antibiotics were assessed by the checkerboard method. The killing assay was used to test possible synergistic effects when blue light was further combined to AgNPs and each antibiotic at a time against selected isolates of MRSA.

Results

The bactericidal activity of AgNPs, at sub-MIC, and blue light was significantly (p < 0.001) enhanced when both agents were applied in combination compared to each agent alone. Similarly, synergistic interactions were observed when AgNPs were combined with amoxicillin, azithromycin, clarithromycin or linezolid in 30–40 % of the double combinations with no observed antagonistic interaction against the tested isolates. Combination of the AgNPs with vancomycin did not result in enhanced killing against all isolates tested. The antimicrobial activity against MRSA isolates was significantly enhanced in triple combinations of AgNPs, blue light and antibiotic, compared to treatments involving one or two agents. The bactericidal activities were highest when azithromycin or clarithromycin was included in the triple therapy compared to the other antibiotics tested.

Conclusions

A new strategy can be used to combat serious infections caused by MRSA by combining AgNPs, blue light, and antibiotics. This triple therapy may include antibiotics, which have been proven to be ineffective against MRSA. The suggested approach would be useful to face the fast-growing drug-resistance with the slow development of new antimicrobial agents, and to preserve last resort antibiotics such as vancomycin.

     

Biosynthesis of silver nanoparticles by natural precursor from clove and their antimicrobial activity

Silver nanoparticles (AgNPs) have attracted the attention of researchers because of their unique properties and applications in various fields, such as medicine, catalysis, textile engineering, and pollution treatment. The green synthesis of AgNPs has many advantages, such as less time requirement, highly stable AgNPs, better control over crystal growth, morphology, ease for scale up, and economic viability. Syzygium aromaticum (clove) was used for the extracellular biosynthesis of AgNPs. Eugenols are the active biomolecules present in clove, responsible for the bioreduction of AgNO₃ (Ag⁺) leading to the formation and capping of AgNPs (Ag⁰). One molecule of eugenol releases two electrons and these two electrons will be taken by 2 Ag⁺ ions and these will get reduced to 2 Ag⁰. The synthesis of AgNPs was confirmed by the appearance of brown colour. The synthesized AgNPs were characterised by various techniques, such as UV-VIS spectroscopy, transmission electron microscopy, X-ray diffraction and Fourier transformed infrared spectroscopy. The synthesised AgNPs have λ _max of 440 nm. It was evaluated that the AgNPs were biphasic in nature (cubic + hexagonal) with an average size of 50.0 nm. The synthesized AgNPs showed significant antimicrobial activity against Bacillus cereus NCDC 240 as they are nano-sized and have high surface area to volume ratio. AgNPs inhibit the growth of bacteria by various ways, such as by disrupting the cell membrane of bacteria, uncoupling the oxidative phosphorylation, inhibiting the DNA replication, forming free radicals and affecting the cellular signalling of bacteria leading to cell death.     

Cellular proliferation/cytotoxicity and antimicrobial potentials of green synthesized silver nanoparticles (AgNPs) using Juniperus procera

Juniperus spp. are used as medicinal plants in many countries like Bosnia, Lebanon, and Turkey. In folk medicines, these plants have been used for treating skin and respiratory tract diseases, urinary problems, rheumatism and gall bladder stones. The objectives of this work were to synthesize silver nanoparticles (AgNPs) using a coniferous tree, Juniperus procera leaf extract and testing the synthesized AgNPs for its antimicrobial potentials, hemolytic activity, toxicity and the proliferative effects against normal and activated rat splenic cells. Leaf extract was prepared using acetone and ethanol as solvents. AgNPs were prepared using the acetone extract. AgNPs were validated using UV–Vis spectroscopy and scanning electron microscopy (SEM). Functional groups in the extract were identified using Fourier Transform Infrared (FT-IR) spectroscopy. SEM images of AgNPs showed spherical and cubic shapes with a uniform size distribution with an average size of 30–90 nm. FT-IR spectroscopy showed the presence of many functional groups in the plant extract. AgNPs showed promising antimicrobial activity against tested bacteria and fungus. AgNPs also expressed a stimulating activity towards the rat splenic cells in a dose dependent manner. Acetone as solvent was safer on cells than ethanol. Green synthesized AgNPs using J. procera might be used as a broad-spectrum therapeutic agent against microorganisms and as an immunostimulant agent.     

Nano silver entrapped in phospholipids membrane: Synthesis,characteristics and antibacterial kinetics

Abstract

The antimicrobial property of stabilized silver nanoparticles (AgNPs) with phospholipid membrane was investigated on both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains. The influence of phospholipid concentrations on antibacterial kinetics actions of AgNPs was studied with two different methodologies in order to understand the bactericidal and bacteriostatic effects. The bacterial inactivation of synthesized AgNPs fitted well to the Chick-Watson model with a high regression coefficient, R² > 0.91. The antibacterial properties of AgNPs depend on the particle size, stabilizer and lecithin concentrations. Only the stabilized AgNPs that have the K_lec/Ag values of 1 and 2 presented the inhabitation zone, while unstabilized AgNPs agglomerated quickly, settled on the wells and did not diffuse in agar. In addition, the specific coefficient of lethality depends on the lecithin concentration. An increase in lecithin concentration caused multilayer creation on the AgNPs' surface and reduced the release of AgNPs which led to low bacterial killing rate.     

Employment of Cassia angustifolia leaf extract for zinc nanoparticles fabrication and their antibacterial and cytotoxicity

The plant Cassia angustifolia belongs to Saudi Arabia, which is one of the native places and now cultured throughout the global countries. Medical care in the Arab world is an essential outlet for medicinal plants, both because they are crucial elements for prophetic medicine and due to their lengthy background in the Middle East. C.angustifolia is one of the medicinal plants used in the Saudi Arabia. The usage of plant extracts for synthesizing nanoparticles is conducive to other biological material, since it avoids the lengthy phase of cell culture maintenance. Silver nanoparticles attract further attention due to their strong conductivity, stability and antimicrobial activity across different metal nanoparticles. The present study was designed in the Saudi C. angustifolia leaves with the zinc synthesis of nanoparticles and its antibacterial ability. The plant extracts of C. angustifolia was used for synthesis of zinc nanoparticles, antimicrobial activities against bacterial strains have been tested along with transmission electron microscope (TEM), UV spectroscopy and antimicrobial activities have been conducted. This study showed that silver ions may be transferred from the plant extract to silver nanoparticles. AgNPs biogenic capacity to antibacterial with lovo cell with IC₅₀ ranged from 33.5 ± 0.2 μg/mL demonstrated strong antibacterial capacity to antibody. The overall absorption value for the extract was between 420 and 440 nm and the color transition to green was the plasma absorption of the AgNPs. TEM results was showed in 200,000 magnification. The uniqueness of the current study is that Cassia angustifolia leaf extract from Saudi Arabia was used to prepare the metallic nanoparticles. Additionally, ZnCl₂ may also be used as nanoparticles of mineral salt and zinc, which, since their application has been confirmed, are antimicrobial.     

Biological nanosilver particles for the protection of archaeological stones against microbial colonization

The inhabitation of microorganisms and their subsequent interaction with mineral matrix of the stone substrate under varied environmental conditions encourages deterioration of stones leading to the loss of strength, durability and aesthetic. This study highlighted the synthesis of nanosilver particles (AgNPs) using the biogenic volatiles of the bacterial strain Nesterenkonia halobia. The antimicrobial activities of AgNPs were evaluated against the gram positive bacterial strain Streptomyces parvullus and fungal strain Apergillus niger. Furthermore, the silver particles were mixed with two types of consolidation polymers and were used to coat the external surfaces of sandstone and limestone blocks. The stones treated with silicon polymer loaded with AgNPs showed an elevated antimicrobial potentiality against A. niger and S. parvullus. Scan electron microscope (SEM) and electron dispersive X-ray spectroscopy (EDX) analysis of treated stones demonstrated the existence of nano-composite structures containing the elemental silver. Polymers functionalized with AgNPs can be used not only as potent biocides but also for the consolidation of the historic monuments and artifacts.     

Silver nanoparticles from Prosopis glandulosa and their potential application as biocontrol of Acinetobacter calcoaceticus and Bacillus cereus

In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs) were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (?200 mV). The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL) showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. glandulosa.     

Nematode-based biomarkers as critical risk indicators on assessing the impact of silver nanoparticles on soil ecosystems

Soil contamination caused by silver nanoparticles (AgNPs) released from sewage treatment plants (STPs) is of great public concern. Understanding the relationships between the physicochemical properties of AgNPs and their toxicity is critical for environmental and health risk analysis. Here we presented an approach for rapidly screening and assessing the potential toxicity risk of AgNPs in general and sludge-treated soils based on the nematode Caenhorhabditis elegans-based probabilistic risk assessment framework. The soil environmental risks were estimated depending on the characteristics of AgNPs and geographic regions. We assessed the risk for soils exceeding a threshold of C. elegans neurotoxicity based on the statistical models. Our results indicated that locomotion inhibition of C. elegans was depending on surface properties, diameter, and exposure time of AgNPs. Here we showed that the overall sewage sludge-released AgNPs-associated soil contamination risk was very low among Europe, U.S., and Switzerland. However, large production and widespread use of AgNPs are highly likely to pose long-term ecotoxicity risk on general and sludge-treated soils, particularly for 26 nm citrate-coated AgNPs. Our approach of integrating probabilistic risk model and C. elegans-based ecological indicator provides an effective tool to rapidly screen and assess the impacts of STPs-released AgNPs on soil environment. We suggest that C. elegans as a proxy for estimating soil risk metrics can help develop methods of management for mitigating the metal NPs-induced toxicity on terrestrial ecosystems.     

Biosynthesis of silver nanoparticles formation from Caesalpinia pulcherrima stem metabolites and their broad spectrum biological activities

The present work illustrates eco-friendly, rapid and cost effective method of AgNPs synthesis using C. pulcherrima stem extract. Initially, various physico chemical factors were optimized. Characterization was done by different spectroscopic and microscopic analysis. AgNPs were spherical in shape with an average size of 8?nm. AgNPs showed good synergistic antimicrobial, antibiofilm and antioxidant activity. The cytotoxicity effect against HeLa cancer cell line was dose dependent while genotoxic study revealed the non toxic nature of AgNPs at lower concentration. The results suggest that AgNPs from C. pulcherrima stem extract have great potential in biomedical applications.     

Melanin-Mediated Synthesis of Silver Nanoparticles and Their Affinity Towards Tyrosinase

The bacterial strain Pseudomonas sp. SSA has capacity to produce extracellular melanin that sequesters heavy metals. The brown-black melanin pigment was observed in the culture liquid and mediated synthesis of silver nanoparticles (AgNPs). The AgNPs were characterized using UV–visible, dynamic light scattering, energy dispersive X-ray, Fourier transform infrared and surface plasmon resonance spectroscopy, scanning electron and transmission electron microscopy and selected area electron diffraction analysis. The synthesized nanoparticles were found to be spherical in shape with size in the range of 14–30 nm and showed high antimicrobial activity against pathogenic bacteria and fungi. These nanoparticles revealed binding affinity towards fungal and human tyrosinases with K_D 4.601 × 10^–10 and 2.816 × 10^–5 M, respectively. In addition, produced nanoparticles did not show any toxic effect towards HeLa cells up to 20 μg/mL. These nanoparticles could find application in medicine and cosmetics due to their enzyme inhibition and antimicrobial activities.     

Silver nanopaticles synthesized using the seed extract of Trigonella foenum-graecum L. and their antimicrobial mechanism and anticancer properties

Background

Synthesis of silver nanoparticles (AgNPs) through biological route plays an important role in their applications in the medical field, especially in the prevention of disease causing microbial pathogens and arresting the propagation of cancer cells. The stable, green synthesis of AgNPs is very much welcomed in the medical field because of their low toxicity. Therefore, the demands of AgNPs synthesised biologically is on the rise. The present study aimed to investigate the antimicrobial mechanisms and anticancer properties of the AgNPs synthesized using the seed extract of Trigonella foenum-graecum L. The AgNPs were characterized by UV–vis, SEM, XRD, FTIR and EDAX analysis. The minimum inhibitory concentrations (MIC) of the AgNPs were determined by the broth micro dilution method.

Biogenic synthesis of silver nanoparticles: Antibacterial and cytotoxic potential

In green chemistry, the application of a biogenic material as a mediator in nanoparticles formation is an innovative nanotechnology. Our current investigation aimed at testing the cytotoxic potential and antimicrobial ability of silver nanoparticles (AgNPs) that were prepared using Calligonum comosum roots and Azadirachta indica leaf extracts as stabilizing and reducing agents. An agar well diffusion technique was employed to detect synthesized AgNPs antibacterial ability on Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus bacterial strains. Furthermore, their cytotoxic capability against LoVo, MDA-MB231 and HepG2 ca cells was investigated. For phyto-chemical detection in the biogenic AgNPs the Fourier-transform infrared spectroscopy (FT-IR) was considered. Zeta sizer, TEM (Transmission Electron Microscope) and FE-SEM (Field Emission Scanning Electron Microscope) were used to detect biogenic AgNPs’ size and morphology. The current results showed the capability of tested plant extract for conversion of Ag ions to AgNPs with a mean size ranging between 90.8 ± 0.8 and 183.2 ± 0.7 nm in diameter. Furthermore, prepared AgNPs exhibited apoptotic potential against HepG2, LoVo, and MDA-MB 231cell with IC₅₀ ranging between 10.9 and 21.4 μg/ml and antibacterial ability in the range of 16.0 ± 0.1 to 22.0 ± 1.8 mm diameter. Activation of caspases in AgNPs treated cells could be the main indicator for their positive effect causing apoptosis. The current investigation suggested that the green production of AgNPs could be a suitable substitute to large-scale production of AgNPs, since stable and active nanoparticles could be obtained.     

Antibiofilm potential of biogenic silver nanoparticles against <Emphasis Type="Italic">Kocuria rosea</Emphasis> And <Emphasis Type="Italic">Kocuria rhizophila</Emphasis>

The present study aims at biosynthesizing, characterizing and evaluating the biogenic silver nanoparticles (AgNPs) as antimicrobial and antibiofilm against Kocuria rosea and Kocuria rhizophila. Cellfree supernatant of Proteus mirabilis culture was used for biosynthesizing AgNPs, which confirmed by visualizing color change and X-ray diffraction. Transmission electron microscopy showed the formation of AgNPs in the range of 5–40 nm. ART-FTIR spectra provided evidence for presence of proteins as possible biomolecules responsible for stability of AgNPs and act as capping agent. AgNPs had ability to inhibit growth of K. rosea and K. rhizophila. The minimum inhibitory concentration (MIC₉₀) of AgNPs against both strains was 25 μg/mL. Antiadhesive effect of AgNPs was verified at sub-MIC₉₀ dose (12.5 μg/mL). The AgNPs concentrations up to 100 μg/mL were not effective for complete removing the already established biofilms with maximum removing percentage of 30.5–34.9%. In conclusion, the present study demonstrated an unprecedented green process for biosynthesizing stable spherical-shaped AgNPs. Early control is suggested by preventing biofilm formation using low AgNPs concentration (12.5 μg/mL) as a potential ingredient for formulating effective chemical sanitizers.     

Biosynthesis of silver nanoparticles using aqueous extract of Phyllanthus acidus L. fruits and characterization of its anti-inflammatory effect against H2O2 exposed rat peritoneal macrophages

The green synthesis and characterization of silver nanoparticles (AgNPs) derived from plants impart ecological and economic benefits to AgNPs. In addition, AgNPs have potential therapeutic roles in cytoprotectivity and anti-inflammation. The present work utilizes the aqueous extract of Phyllanthus acidus fruits for the production of AgNPs from aqueous silver nitrate solution. The synthesized AgNPs were characterized spectrophotometrically Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy analysis. The characterized AgNPs showed potent anti-inflammatory activity by scavenging nitric oxide and superoxide anions. In addition, blunting of the expression of pro-inflammatory cytokine interleukin 1 beta (IL-1β) assayed both by ELISA and Western blot, using H₂O₂ – induced inflammation in rat peritoneal macrophages. Furthermore, short-term exposure to P. acidus-mediated green-synthesized AgNPs did not affect the viability of peritoneal macrophages, as assessed by MTT assay. Our findings indicate that P. acidus-mediated green-synthesized AgNPs could be a potential therapeutics to treat inflammatory diseases.