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268 result(s) for "Silver nanoparticles (Ag NPs)"
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Shape-dependent antimicrobial activities of silver nanoparticles
An important application of silver nanoparticles (Ag NPs) is their use as an antimicrobial and wound dressing material. The aim of this study is to investigate the morphological dependence on the antimicrobial activity and cellular response of Ag NPs. Ag NPs of various shapes were synthesized in an aqueous solution using a simple method. The morphology of the synthesized Ag NPs was observed via TEM imaging. The antimicrobial activity of the Ag NPs with different morphologies was evaluated against various microorganisms ( [ ] [ ] [ ]). The antimicrobial activity of the Ag NPs was also examined according to the concentration in terms of the growth rate of . The TEM images indicated that the Ag NPs with different morphologies (sphere, disk and triangular plate) had been successfully synthesized. The antimicrobial activity obtained from the inhibition zone was in the order of spherical Ag NPs > disk Ag NPs > triangular plate Ag NPs. In contrast, fibroblast cells grew well in all types of Ag NPs when the cell viability was evaluated via an MTT assay. An inductively coupled plasma mass assay showed that the difference in the antimicrobial activities of the Ag NPs was closely associated with the difference in the release rate of the Ag ions due to the difference in the surface area of the Ag NPs. The morphological dependence of the antimicrobial activity of the Ag NPs can be explained by the difference in the Ag ion release depending on the shape. Therefore, it will be possible to control the antimicrobial activity by controlling the shape and size of the Ag NPs.
A Robust Nanocatalyst Incorporating Multi‐Walled Carbon Nanotubes Infused with Magnetic Nanoparticles and Biguanide–Silver Nanoparticles for Multicomponent Synthesis of Benzopyrano‐Pyrimidines
A highly efficient and environmentally friendly synthetic method has been developed for the preparation of benzopyrano‐pyrimidines using multi‐walled carbon nanotubes/magnetic nanoparticles‐Biguanide‐Ag NPs as a heterogeneous nanocatalyst in choline chloride–urea (ChCl–Urea) deep eutectic solvent. This approach offers numerous advantages, including high isolated yields (86–99%) and short reaction times (10–70 min), along with broad substrate compatibility for both electron‐donating and electron‐withdrawing functional groups. The method exhibits excellent catalytic efficiency, with high turnover numbers and turnover frequencies, even at low catalyst loading. The use of ChCl–Urea as a green, biodegradable, and nonvolatile solvent aligns with sustainable chemistry principles and allows for easy solvent recovery. Additionally, the magnetic nanocatalyst is easily recoverable and reusable, maintaining activity over multiple cycles. Operational simplicity, mild conditions, and one‐pot multi‐component reaction design further enhance the method's scalability and synthetic utility. Given the biological relevance of benzopyrano‐pyrimidines, this strategy presents a valuable platform for green synthesis in medicinal chemistry and pharmaceutical development. A highly efficient and environmentally friendly synthetic method has been developed for the preparation of benzopyrano‐pyrimidines using MWCNTs/MNPs‐Biguanide‐Ag NPs as a heterogeneous nanocatalyst in choline chloride–urea (ChCl–Urea) deep eutectic solvent.
Nanosilver: new ageless and versatile biomedical therapeutic scaffold
Silver nanotechnology has received tremendous attention in recent years, owing to its wide range of applications in various fields and its intrinsic therapeutic properties. In this review, an attempt is made to critically evaluate the chemical, physical, and biological synthesis of silver nanoparticles (AgNPs) as well as their efficacy in the field of theranostics including microbiology and parasitology. Moreover, an outlook is also provided regarding the performance of AgNPs against different biological systems such as bacteria, fungi, viruses, and parasites (leishmanial and malarial parasites) in curing certain fatal human diseases, with a special focus on cancer. The mechanism of action of AgNPs in different biological systems still remains enigmatic. Here, due to limited available literature, we only focused on AgNPs mechanism in biological systems including human (wound healing and apoptosis), bacteria, and viruses which may open new windows for future research to ensure the versatile application of AgNPs in cosmetics, electronics, and medical fields.
Rapid Detection of Carbendazim Residue in Apple Using Surface-Enhanced Raman Scattering and Coupled Chemometric Algorithm
In order to achieve rapid and precise quantification detection of carbendazim residues, surface-enhanced Raman spectroscopy (SERS) combined with variable selected regression methods were developed. A higher sensitivity and greater density of “hot spots” in three-dimensional (3D) SERS substrates based on silver nanoparticles compound polyacrylonitrile (Ag-NPs @PAN) nanohump arrays were fabricated to capture and amplify the SERS signal of carbendazim. Four Raman spectral variable selection regression models were established and comparatively assessed. The results showed that the bootstrapping soft shrinkage-partial least squares (BOSS-PLS) method achieved the best predictive capacity after variable selection, and the final BOSS-PLS model has the correlation coefficient (RP) of 0.992. Then, this method used to detect the carbendazim residue in apple samples; the recoveries were 86~116%, and relative standard deviation (RSD) is less than 10%. The 3D SERS substrates combined with the BOSS-PLS algorithm can deliver a simple and accurate method for trace detection of carbendazim residues in apples.
Synthesis and Application of Silver Nanoparticles (Ag NPs) for the Prevention of Infection in Healthcare Workers
Silver is easily available and is known to have microbicidal effect; moreover, it does not impose any adverse effects on the human body. The microbicidal effect is mainly due to silver ions, which have a wide antibacterial spectrum. Furthermore, the development of multidrug-resistant bacteria, as in the case of antibiotics, is less likely. Silver ions bind to halide ions, such as chloride, and precipitate; therefore, when used directly, their microbicidal activity is shortened. To overcome this issue, silver nanoparticles (Ag NPs) have been recently synthesized and frequently used as microbicidal agents that release silver ions from particle surface. Depending on the specific surface area of the nanoparticles, silver ions are released with high efficiency. In addition to their bactericidal activity, small Ag NPs (<10 nm in diameter) affect viruses although the microbicidal effect of silver mass is weak. Because of their characteristics, Ag NPs are useful countermeasures against infectious diseases, which constitute a major issue in the medical field. Thus, medical tools coated with Ag NPs are being developed. This review outlines the synthesis and utilization of Ag NPs in the medical field, focusing on environment-friendly synthesis and the suppression of infections in healthcare workers (HCWs).
In vitro effect of gold and silver nanoparticles on human spermatozoa
Summary The cytotoxicity of Au/Ag nanoparticles (NPs) on human spermatozoa was investigated in vitro. Semen from donors were incubated (37 °C, 60′–120′) with 30, 60, 125, 250 and 500 μM Au/Ag‐NPs. Sperm motility was evaluated following WHO guidelines; sperm viability was assessed with eosin Y test. Au‐NPs were characterised and localised with field emission gun‐based scanning transmission electron microscope/energy dispersive spectroscopy and transmission electron microscopy. Both tested NPs exerted a significant dose‐dependent effect on motility and viability of human spermatozoa (P < 0.001). Ag‐NPs seem to show a slightly elevated toxicity although not significant (P > 0.05). Au‐NPs were localised in spermatozoa, whereas Ag‐NPs were undetectable. In conclusion, Au‐NPs and Ag‐NPs do not appear to be harmful for human spermatozoa up to high concentrations (250–500 μM) that are probably difficult to reach in vivo. It is mandatory to explore the genotoxic effect of NPs in germ cells.
SERS Substrate Based on Ag Nanoparticles@Layered Double Hydroxide@graphene Oxide and Au@Ag Core–Shell Nanoparticles for Detection of Two Taste and Odor Compounds
Sulfide organics and phenols are ubiquitous in freshwater lakes all over the world. As two taste and odor (T and O) compounds, they are harmful to the environment and human body. The existing detection methods for T and O compounds mainly include sensory analysis and gas-phase mass spectrometry, which are cumbersome and time-consuming. Herein, a method for the simultaneous and rapid detection of two T and O compounds (methyl sulfide and 2,4-di-tert-butylphenol) based on surface-enhanced Raman spectroscopy (SERS) is firstly developed. The SERS substrate was prepared by coating Ag nanoparticles (Ag NPs), layered double hydroxide (LDH), and graphene oxide (GO) on the surface of an Ag-coated Au nanoparticle (Au@Ag NP) substrate. Under optimal conditions, this SERS substrate possessed low detection limits of 1.53 ppm for methyl sulfide and 0.39 ppm for 2,4-di-tert-butylphenol. In addition, it took only 20 min to complete the detection using this method, without complex sample pretreatment. Furthermore, it was successfully applied to simultaneously detect methyl sulfide and 2,4-di-tert-butylphenol in actual water samples and had good application prospects for the rapid detection of T and O compounds in water.
Cytotoxic Effects of ZnO and Ag Nanoparticles Synthesized in Microalgae Extracts on PC12 Cells
The green synthesis of silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs), as well as Ag/Ag2O/ZnO nanocomposites (NCs), using polar and apolar extracts of Chlorella vulgaris, offers a sustainable method for producing nanomaterials with tunable properties. The impact of the synthesis environment and the nanomaterials’ characteristics on cytotoxicity was evaluated by examining reactive species production and their effects on mitochondrial bioenergetic functions. Cytotoxicity assays on PC12 cells, a cell line originated from a rat pheochromocytoma, an adrenal medulla tumor, demonstrated that Ag/Ag2O NPs synthesized with apolar (Ag/Ag2O NPs A) and polar (Ag/Ag2O NPs P) extracts exhibited significant cytotoxic effects, primarily driven by Ag+ ion release and the disruption of mitochondrial function. However, it is more likely the organic content, rather than size, influenced anticancer activity, as commercial Ag NPs, despite smaller crystallite sizes, exhibit less effective activity. ZnO NPs P showed increased reactive oxygen species (ROS) generation, correlated with higher cytotoxicity, while ZnO NPs A produced lower ROS levels, resulting in diminished cytotoxic effects. A comparative analysis revealed significant differences in LD50 values and toxicity profiles. Differentiated PC12 cells showed higher resistance to ZnO, while AgNPs and Ag/Ag2O-based materials had similar effects on both cell types. This study emphasizes the crucial role of the synthesis environment and bioactive compounds from C. vulgaris in modulating nanoparticle surface chemistry, ROS generation, and cytotoxicity. The results provide valuable insights for designing safer and more effective nanomaterials for biomedical applications, especially for targeting tumor-like cells, by exploring the relationships between nanoparticle size, polarity, capping agents, and nanocomposite structures.
Plant growth and diosgenin enhancement effect of silver nanoparticles in Fenugreek (Trigonella foenum-graecum L.)
Various methods have been used to enhance production of chemically diverse phytochemicals especially medicinal natural products. With the advancement in nanotechnology, nanoparticles have been reported to have varying impact in plant growth and inducibility of phytochemical composition. Major objective of the study was to study the secondary metabolite modulatory effect of silver nanoparticles. In the current study, treatment of fenugreek seedlings with biosynthesized silver nanoparticles (Ag-NPs) was found to have significant impact on its growth parameters such as leaf number, root length, shoot length and wet weight. On HPLC based analysis, Ag-NPs treated seedlings showed an enhancement in the production of major phytochemical diosgenin to a level of 214.06±17.07μg/mL. An untreated control gave an yield of only 164.44±7.67μg/mL of diosgenin, and the observed phytochemical enhancement effect induced by Ag-NP was very significant. Most remarkably, the Ag-NP used in the study was found to play dual role of enhancement of both plant growth and diosgenin synthesis. Hence the study is of immense application as it opens up development of new methods based on nanoelicitors to enhance the biosynthesis of medicinal natural products in plants.
Flexible Transparent Electrode Based on Ag Nanowires: Ag Nanoparticles Co-Doped System for Organic Light-Emitting Diodes
Flexible organic light-emitting diodes (FOLEDs) have promising potential for future wearable applications because of their exceptional mechanical flexibility. Silver nanowire (Ag NW) networks are the most promising candidates to replace indium tin oxide (ITO), which is limited by its poor bendability. In this study, three different methods including methanol impregnation, argon plasma treatment, and ultraviolet radiation were used to reduce the junction resistance of Ag NWs to optimize the flexible transparent electrodes (FTEs); which were prepared using Ag NWs and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS). Then, the optoelectronic properties of the FTEs were further improved by using a co-doped system of silver nanowires and silver nanoparticles (Ag NPs), the structure of which consisted of PET/Ag NWs: Ag NPs/PEDOT: PSS/DMSO. The largest FOM value of 1.42 × 10−2 ohm−1 and a low sheet resistance value of 13.86 ohm/sq were obtained using the optimized FTEs. The prepared FOLED based on the optimized FTEs had a luminous efficiency of 6.04 cd/A and a maximum EQE of 1.92%, and exhibited no observed decline in efficiency when reaching maximum luminance. After 500 bending tests, the luminance still reached 82% of the original value. It is demonstrated that the FTEs prepared via the co-doped system have excellent optoelectronic properties as well as high mechanical stability.