جستجوی مقالات مرتبط با کلیدواژه « agnps » در نشریات گروه « پزشکی »

This study aimed at investigating how treatment of basil seedlings with green synthesized AgNPs affects their Ag content, oxidative damage and antioxidant enzymes activity. This research was studied as a completely randomized design in four replications. Four levels of silver nanoparticles (0, 4, 10 and 40 mg L-1) were used. After germination, the seedlings were treated for 7 days and then seedlings were harvested for analysis. Findings showed that AgNP treatment increased Ag content O2•−, H2O2, MDA, and ion leakage in basil seedlings. The use of AgNPs caused a significant increase in the activities of SOD, APX, CAT, and GR enzymes in plants. However, at high levels (40 mg L-1) of AgNPs, enzymes activity decreased significantly. These findings suggest that the application of green synthesized AgNPs to basil seedlings led to oxidative stress. Moreover, the observed changes in radical scavenging enzyme activity indicate that synthetic green nanoparticles have a harmful effect on basil seedlings. This toxicity is more pronounced at higher concentrations.

The new novel polymers nanocomposites based modified chitosan (CS) blending with polyvinyl alcohol (PVA) and coated gold or silver nanoparticles (AuNPs), (AgNPs) were synthesized from many sequence reactions as presented in (Scheme1, 2 and 3). By utilizing 1H-NMR spectroscopy, FTIR, and Field Emission Scanning electron microscope , the synthesized compounds have been identified. Molecular docking is studied, where operations are used to predict the binding status of compounds with the enzyme and to calculate the free energy (ΔG) of the compounds prepared. Also, the antibacterial activity regarding the synthesized compounds against two resistant pathogenic bacteria (G+) S. aureus and E. coli (G-) was examined in vitro compare with standard antibiotic (Amoxicillin). The cytotoxic effect of novel polymers nanocomposites against Human Lung Adenocarcinoma Cells line (A549) using MTT assay was used to estimate and compare with normal cell line Rat Embryonic Fibroblasts (REF), the (modified chitosan/PVA/Au) exhibited very excellent inhibition rate. Finally, the Acute Toxicity Test of these nanocomposities were examined showed non-toxicity of these nanocomposities and histological examination of internal organs: liver, lung and kidney related to treated group showed no changes but similar those of control group.

The present study explores the green approach for the preparation of silver nanoparticles (AgNPs) through the reduction of silver nitrate by the cell-free stem and leaf aqueous extracts of Litsea glutinosa (L.glutinosa) and its potential antibacterial activity. The analytical instruments include scanning electron microscopy, Fourier transforms infrared spectroscopy, UV-visible spectroscopy, and X-ray diffraction spectroscopy confirmed the synthesis of smaller, uniformly spherical AgNPs (10-40 nm). The average crystalline size of prepared AgNPs produced by L. glutinosa leaf extract was found to be 19 mm. From UV-visible spectral analysis, the maximum absorbance peak appeared at 444 nm for leaf extract AgNPs different from stem extract AgNPs (422 nm), which are found to be specific for AgNPs. The L.glutinosa stem extract-assisted AgNPs have shown significant antibacterial activity against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) in comparison to Gentamycin. Hence, the AgNPs obtained by green synthesis can be therapeutically explored against bacterial infections.

Recently, the applications of a high number of available products containing nanoparticles, especially metallic silver nanoparticles (AgNPs), have significantly increased worldwide. In this review, an attempt is made to critically explain methods of AgNPs production, including chemical, physical, microemulsion, UV-initiated photoreduction, photoinduced reduction, electrochemical, microwave-assisted, irradiation, and green synthetic methods. Different methods are used for the detection of synthetized Ag NPs. The most common methods are UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX). Also, the applications of AgNPs in different fields of medicine, including the treatment of infections caused by bacteria, fungi, and viruses, as well as fatal human diseases such as cancer and nervous diseases, are discussed. In addition to the studies that are discussed in this review, it is necessary to conduct further studies on the toxicity of AgNPs in relation to vital organisms.

The probability of contracting an infection when implanting an Stainless Steel 316L (SS316L) implant has been increasing. Infection due to implant placement is called osteomyelitis which is bone inflammation caused by biofilms formed by pyogenic bacteria. Biofilms can be prevented by giving antibacterial agents. This study aims to examine the potential of silver nanoparticles (AgNPs) as an antibacterial agent in SS316L implants. AgNPs are made through a chemical synthesis process using the Gallic acid reduction method. AgNPs solution with 5 variations of precursor concentration, namely 0.1 mM, 1 mM, 10 mM, 100 mM each added with gelatin was sprayed on SS316L by the airbrush spray coating method with a distance between nozzle and substrate of 20 cm at a pressure of 40 psi. AgNPs solutions produced from various concentrations of AgNO3 precursors have a range of λmax = 401.5 nm- 424.5 nm and a particle size distribution of 0.97 - 4.88 nm. The AgNPs layer on SS316L was characterized by its crystalline phase, crystal size, and anti-bacterial activity. It has a cubic structure with a phase fraction of 6.5-19%. Based on the antibacterial activity test, all AgNPs layer samples had inhibitory zone diameters in the range of 12-16 mm. AgNPs (10mM) + Gelatin layer showed the best antibacterial ability with an inhibitory zone diameter of 16.63 mm. The variation in the concentration of the 10 mM AgNPs precursor-Gelatin can be developed into a coating on the surface of the SS316L implant material.

Aedes mosquitoes are the most important group of vectors having ability of transmitting pathogens in cluding arboviruses that can cause serious diseases like Chikungunya fever, Dengue fever and Zika virus in human. Biosynthesis and the use of green silver nanoparticles (AgNPs) is an important step in the search of reliable and eco friendly control of these vectors.

In this study an aqueous leaves extract of Ricinus communis (castor) and silver nanoparticles (AgNPs) syn thesized from this extract were evaluated as larvicidal agent for 2nd and 3rd instar larvae of the Aedes albopictus. Differ ent concentrations (50, 100, 150, 200 and 250ppm) of plant extract and synthesized nanoparticles were prepared and applied on second and third instar larvae. The percent mortality was noted after 6, 12, 18, 24, 30, 36, 42 and 48H of exposure and subjected to probit analysis to calculate LC50 and LC90.

Synthesized Ag+ nanoparticles were characterized by UV-Vis spectroscopy, Fourier transform infrared spec troscopy (FT-IR), and energy-dispersive X-ray spectroscopy (XRD). The nanoparticles were more toxic against larvae of Ae. albopictus with LC50 value (49.43ppm) and LC90 value (93.65ppm) for 2nd instar larvae and LC50 (84.98ppm) and LC90 (163.89ppm) for 3rd instar larvae as compared to the plant extract (149.58ppm, 268.93ppm) and (155.58ppm, 279.93ppm) for 2nd and 3rd instar larvae of Ae. albopictus respectively after 48H.

Our results suggest the extract of R. communis and synthesized nanoparticles as excellent replacement of chemical pesticides to control the vector mosquitoes.

The aim of this study was to expand an ecofriendly route for the fabrication of spherical shape silver nanoparticles (AgNPs) using an aqueous extract of Leucaena leucocephala L. leaves to act as stabilizing and reducing agent. Several biomolecules present in plant extract are accountable for single step reduction of metal ions into nanoparticles. The synthesized AgNPs were characterized by X-ray diffraction (XRD) profile, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS) and Photoluminescence. Besides these, AgNPs evinced potent antibacterial, antimalarial and antimycobacterial activity against Pseudomonas aeruginosa, Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Bacillus subtilis, Plasmodium falciparum and Mycobacterium tuberculosis. The results suggest that the efficiently synthesized AgNPs can be used as potential candidates for various medicinal applications in bionanotechnology based industries.

Silver nanoparticles have been widely used as new potent antimicrobial agents in cosmetic and hygienic products, as well as in new medical devices. Serious concerns have been expressed on the potential health risks of dermal applications of nanosilver containing consumer products (AgNPs), therefore regulatory health risk assessment has become necessary for the safe usage of AgNPs in biomedical products with special emphasis to their dermal toxicity potentials. We aimed in the present study to compare the dermal toxicity of three different AgNP containing disinfectantsin an albino rabbit model and tried to determine the role of size and other physicochemical properties on their possible dermal toxicity. After the characterization of all three samples by transmission electron microscopy (TEM), X-Ray Diffraction (XRD) and Dynamic Light Scattering (DLS) , corrosive and irritant potentials  of AgNPs in three different sizes of three colloidal AgNPs were scored by the OECD 404 guideline with necessary modifications and were applied under the specified concentrations via nanosilver skin patches on the shaved skin of young female albino rabbits. All skin reactions were recorded in 3 min as well as in 1, 4, 24, 48 and 72 hours from the application and compared with the control group and followed up for 14 days. Although short-term observations didn’t show any significant changes in the weight of animals and macroscopic  variables, long-term histopathological abnormalities were seen in the skin of all test groups, which was not associated with the size and other physicochemical properties of AgNP samples. The toxicity manifestations were dry skin, scaling in doses lower than 100 ppm and erythema in higher doses up to 4000 ppm which was reversed. This finding creates a new issue in the possible dermal effects of all colloidal AgNPs, containing nano health products, which should be considered in future studies by focusing on other physicochemical properties of AgNPs and possible underlying mechanisms of toxicity by conducting cellular models.

The extensive application of silver nanoparticles (AgNPs) has been increased due to their antimicrobial properties, however numerous concerns has been arisen about their toxicity potential. Since nanoparticles can cross through the placenta and accumulate in the embryonic organs especially liver, in this study, developmental hepatotoxicity of AgNPs was investigated.
Pregnant rats were divided into two groups, vehicle control group and treated group. Treated group received AgNPs (25 mg/kg) through intra-gastric gavage in a period of gestational days 1-19. Pups were sacrificed after the birth and their livers collected. Histopathology, ICP- mass spectrometry, Spectrophotometric assay and ELISA were employed to evaluate AgNPs toxicity in the liver of pups.
Glutathione peroxidase (GPX) activity and glutathione (GSH) level were significantly decreased and malondialdehyde (MDA) and caspase 9 levels were significantly increased, although there was no significant change in caspase 8 content in the liver of offspring. Fatty degeneration and congested dilated sinusoids were also observed in histo-pathological examination.
These results suggest that maternal oral exposure to AgNPs may induce oxidative stress and apoptosis in the liver of their offspring. Further investigations are required to clarify molecular events behind this happening.

Silver Nanoparticles (AgNPs) have gained considerable interests during the last decade due to their excellent antimicrobial activities. Despite their extensive use, the potential toxicity of these nanoparticles and possible mechanisms by which they may induce adverse reactions have not received sufficient attention and no specific biomarker exist to describe and quantify their toxic effects. Nanoparticles, depending on their physicochemical characteristics and compositions, can interact with vital organs such as the brain and induce toxic effects. A specific concern is that any contact with AgNPs independent of the route of administration is thought to result in significant systemic uptake, internal exposure of sensitive organs, especially in the central nervous system (CNS) and different toxic responses. There are considerable evidences that AgNPs can disrupt the Blood-Brain Barrier (BBB) and induce subsequent brain edema formation. Therefore, it is essential to understand the differential effects of AgNPs on brain cell with especial emphasis on the possible mechanisms of action. Recently, biomarkers are increasingly used as surrogate indicators of toxic responses in biological monitoring due to the inaccessibility of target organs. Moreover, as the most nanoscale contaminants occur at low concentrations, physiological biomarkers may be better indicators of potential impact of nanomaterials than traditional toxicity testing. This review aims to investigate the effects of AgNPs on CNS targets of toxicity and clarify the role of existing biomarkers especially the role of dopamine levels as a potential biomarker of Ag-NPs neurotoxicity.

Serious concerns have been expressed about potential health risks of Nano silver containing consumer products (AgNPs) therefore regulatory health risk assessment on such nanoparticles has become mandatory for the safe use of AgNPsinbiomedicalproducts with special concerns to the mutagenic potentials. In this study, we examined the inhibitory and mutagenicity effects of AgNPs in three different sizes of three colloidal AgNPs by Minimal Inhibitory concentration (MIC), Minimal Bactericidal Concentration (MBC) and Bacterial Reverse Mutation Assay (Ames test).All samples were characterized by transmission electron microscopy (TEM), X-Ray Diffraction (XRD) and Dynamic Light Scattering (DLS). DLS analysis showed lack of large agglomeration of the AgNPs and TEM results showed the spherical AgNPswith the average sizes of 15, 19.6, 21.8 nms. Furthermore the XRD analysis showed the crystalline samples with a face centered cubic structure of pure silver.AmestestresultsonColloidal silver nanoparticles showed lack of any mutation in TA100, TA98, YG1029S. typhymuriumstrains.In addition colloidal silver nanoparticles reduced the mutation ratesin all three strains in a concentration dependent manner. This finding creates a new issue in the possible antimutagenic effects of colloidal AgNPsas a new pharmaceutical productwhich should be consideredinfuture studiesby focusing onthephysicochemical properties of AgNPs.