Papers by Keyword: Silver Nanoparticle

Abstract: Organic solar cells (OSCs) have significant challenges with limited light absorption and low efficiency. This study investigates enhancing OSC performance through plasmonic effects by incorporating silver nanoparticles (AgNPs) into the hole transport layer (PEDOT:PSS). AgNP concentrations systematically varied in PEDOT:PSS (0.2%, 0.4%, 0.6%, and 0.8%) and studied their effects on device performance using UV-vis spectroscopy and current-voltage measurements. The OSC device with 0.8% AgNPs revealed a 39% increase in light absorption within the active poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) across the visible and ultraviolet spectrum, leading to a power conversion efficiency of 5.99% - twice that of the reference device. The enhanced performance is attributed to localised surface plasmon resonance effects, which improve carrier generation. These findings demonstrate a promising approach for enhancing OSC efficiency through plasmonic enhancement.

Abstract: The study examines the effects of silver and gold nanoparticles on blood flow in stenosed arteries. The evaluation part of a mathematical model that consisted of linked partial differential equations. These equations have been resolved using the FTCS scheme, along with suitable boundary conditions. The velocity and concentration, temperature, wall shear stress, and volumetric flow rate are all demonstrated with the help of numerical solutions. These are necessary for understanding the impact of different parameters. The present study contributes to the biomedical field by examining the impact of gold and silver nanoparticles on blood flow, which is measured by concentration, wall shear stress, volumetric flow rate, velocity, and temperature, for various values of dimensionless parameters. This understanding is important for the treatment of cardiovascular diseases.Keywords: Stenosis Artery; Gold Nanoparticle; Silver Nanoparticle.

Abstract: The development of non-enzymatic glucose biosensor has been the concern of many researchers mainly because enzymes based sensor despite having excellent sensitivity and selectivity, has the limitations such as poor stability, complicated enzyme immobilization, critical operating conditions such as optimum temperature and reproducibility. This study developed a cheap biocompatible non-enzymatic glucose biosensor based on silver nanoparticle (AgNPs) stabilized with sodium tripolyphosphate (NaTPP) cross-linked chitosan. Direct electron transfer and electro-catalytic activity of the AgNPs modified glassy carbon electrode (AgNPGCE) was investigated using potentiometric and amperometric techniques. AgNPs was prepared and characterized by Fourier transform Infra-red spectroscopy (FTIR), X-ray diffractometry (XRD) and Scanning electron microscopy (SEM). The crystalline size of the AgNPs was revealed with XRD. However, the SEM micrograph of AgNPs revealed the spherical shape with a non-uniform granular shape attributed to bio-mediated ionic gelation process. The FTIR spectra of AgNPs shown peaks at 1054 – 1645 cm^-1 suggesting the presence of phosphonate linkages between ammonium, -NH₃⁺ of chitosan and -PO₃^2- moieties of NaTPP during cross linking process. Electro-catalytic oxidation of glucose at the AgNPGCE surface and the mechanism involved in glucose oxidation was revealed via cyclic voltammetry. The AgNPGCE showed a better electrochemical response towards glucose. This glucose sensor showed high sensitivity at +0.54 V. A low detection limit of 1.22 µM (the confident level κ = 3), and wide linear range of 2 to 24 µM with a correlation coefficient of 0.9987 were obtained. The calculated parameters revealed that AgNPGCE had shown better overall electrochemical performance and response than enzymatic biosensor.

Abstract: The research describes a new method for silver core-tin oxide shell nanoparticle preparation suitable for shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) investigation. The two-step synthesis was performed without intermediate separation. Silver nitrate precursor, sodium citrate reducer, and diethylene glycol stabilizer were used resulting in the formation of large (80 ± 5 nm) silver nanospheres. A thin (8 – 12 nm) tin oxide shell was successfully produced in 40 minutes in an alkaline solution. The synthesized silver core-tin oxide shell nanoparticles demonstrated good stability in weakly acidic (pH 5), neutral (pH 7), and basic (pH 9) media. Long-term (2 – 4 months) stability experiments were also successfully performed in water, acetone, and ethanol. The nanoparticles were applied in the SHINERS study of the classic 4-mercaptobenzoic acid monolayer on Au, highlighting their potential for wider analytical application. The paper provides a detailed explanation of the synthesis, analysis, and application of the silver core-tin oxide shell nanoparticles based on data from UV-Vis, HR-TEM, and SHINERS.

Abstract: The development of bioplastics is currently increasing, because bioplastics are an effort to reduce landfill waste. One of the bioplastics that has good degradation ability is cornstarch. The addition of nanoparticles was carried out to improve the properties of bioplastic packaging. One example of the application of nanotechnology in food packaging is silver nanoparticles (AgNP), known as antimicrobial substances. This research was conducted to determine the effect of adding AgNP (0%, 1%, and 2%) on the antimicrobial and biodegradation of cornstarch bioplastics. Bioplastics are made by casting method. AgNP was used from the synthesis of silver nitrate (AgNO₃) and trisodium citrate dihydrate (C₆H₅Na₃O₇.2H₂O) as a reducing agent and stabilizer by chemical reduction method, which was then analyzed by FTIR. The results obtained showed that cornstarch bioplastic AgNP 1% has the ability to estimate the fastest degradation time among other concentrations with an addition of 103 days. Cornstarch bioplastic AgNP 2% had the best ability to inhibit bacterial growth, with antibacterial inhibition zone diameters of 11.03 mm (Staphylococcus aureus) and 10.61 mm (Escherichia coli). However, AgNP could not inhibit the mold growth of Aspergillus niger. The addition of AgNP to cornstarch bioplastics can increase the degradation capabilities and antibacterial activity of bioplastics.

Abstract: Electromyography (EMG) is a method for measuring muscle biopotential signals for monitoring muscle activity. Electrodes are placed on the skin to capture EMG signals from muscles underneath. The most common electrodes used in clinical EMG measurement are Ag/AgCl electrodes in the form of metal plates coated with electrode gel. Electrode gel enhances the contact between the electrode’s metal plate and the skin since it is essential for a good measurement signal quality. Meanwhile, flexible electrodes are made from flexible conductive materials that can be adjusted to the contour of the skin surface; therefore, they can improve the measured biopotential signal quality. This study developed a carrageenan-based bioplastic with the addition of graphite and silver nanoparticles (AgNP) hybrid as a flexible electrode for EMG signal measurement. Fabrication of graphite and AgNP hybrid starts with the functionalization of the graphite powder in a mixture of HNO₃ and H₂SO₄. Next, AgNPs were added using the electrochemical method by utilizing SnCl2 and functionalized graphite powder to form an Ag-Sn/Graphite (Graphite-AgNPs) hybrid conductive material. In order to incorporate conductive materials into bioplastic, the Graphite-AgNPs hybrid conductive material is then mixed into the carrageenan-based bioplastic mixture. It is found that 25% w/w addition of these conductive materials already gives good electrical conductivity. The best electrical conductivity value was determined by varying several conductive material types and concentrations. Finally, the EMG signal was measured with the bioplastic flexible electrodes, and the performance was compared with the commercial Ag/AgCl electrodes.

Abstract: Nanomedicine has been used in tumor treatment and research due to its advantages of targeting, controlled release and high absorption rate. Silver nanoparticle (AgNPs), with the advantages of small particle size, and large specific surface area, are of great potential value in suppressing and killing cancer cells. Methods: AgNPs–polyethyleneimine (PEI) –folate (FA) (AgNPs–PF) were synthesised and characterised by several analytical techniques. The ovarian cancer cell line Skov3 was used as the cell model to detect the tumor treatment activity of AgNPs, AgNPs–PF and AgNPs+ AgNPs–PF. Results: Results shown that AgNPs–PF were successfully constructed with uniform particle size of 50–70 nm. AgNPs, AgNPs–PF, AgNPs–PF+ AgNPs all showed a certain ability to inhibit cancer cell proliferation, increase reactive oxygen species and decrease the mitochondrial membrane potential. All AgNPs, AgNPs–PF, AgNPs+ AgNPs–PF promoted DNA damage in Skov3 cells, accompanied by the generation of histone RAD51 and γ-H2AX site, and eventually leading to the apoptosis of Skov3 cells. The combination of AgNPs–PF and AgNPs had a more pronounced effect than either material alone. Conclusion: This study is to report that the combination of AgNPs+ AgNPs–PF can cause stronger cytotoxicity and induce significantly greater cell death compared to AgNPs or AgNPs–PF alone in Skov3 cells. Therefore, the combined application of drugs could be the best way to cancer treatment.

Abstract: In the present study, a simple and fast approach was developed for the green synthesis of silver nanoparticles by using Eryngium campestre (Eryngo) extract prepared in boiling water. People have widely used the Eryngo plant as a vegetable, food, and medicine around the world. The dried leaves of Eryngo extracted in boiling water yielded approximately 67 mg/g (6.6%) solid residue. The extract had a high antioxidant activity of 71 %, which was rich in total phenolic and flavonoids as revealed through colorimetric assays. For preparing nanoparticles, silver nitrate was added to the plant extract diluents and kept until the solution color changed with a sharp indicative peak of AgNPs that appeared at 450 nm. In addition, UV/Vis, TEM, FESEM, DLS, EDS, and XRD analysis were used to characterize the as-synthesized AgNPs. The results confirmed the spherical shape and nano nature of AgNPs with an average size of 32 nm based on Fe-SEM and TEM observations. The prepared AgNPs also shown moderate free radical scavenging activity (60%) in DPPH test and exhibit antibacterial activity at low concentration (50 μg/mL) toward both gram-positive and gram-negative bacteria. In this respect, the inhibition zone was higher in gram-positive bacteria and the sensitivity order of S.aureus > MRSA > B.subtilis > P.aeruginosa > E.coli was achieved in response to Eryngo AgNPs. Interestingly, Eryngo AgNPs at low concentration were efficient on MRSA, as an antibiotic-resistant strain of S.aureus.

Abstract: The present study evaluates the toxicity of AgNPs synthesised from Padina tetrastromatica (P-AgNPs) through Brine Shrimp Lethality Assay. The aqueous Padina seaweed extract was treated with AgNO₃ to synthesise P-AgNPs, and these NPs were then characterised by multiple analytical techniques. The UV-Vis spectra displayed characteristic SPR peaks of AgNPs at about 409.5 nm. The TEM and particle size distribution results verified the formation of polydisperse spherical P-AgNPs with a dominant size of around 48 nm. Zeta potential analysis indicates the moderate stability of P-AgNPs. The FTIR spectrum of P-AgNPs reveals the presence of organic functional groups, suggesting the involvements of seaweed organic matters in capping and stabilising AgNPs. Though the 24-h mortality test showed a dose-dependent increase in Artemia death, the results imply a non-toxic property in P-AgNPs (LC₅₀ value: 4300 mg/L; >1000 mg/L). These findings conclusively suggest the acute exposure to P-AgNPs has no substantial risk to marine organisms.

Abstract: Agar and banana (Gros Michel) powder composite film with silver nanoparticles were prepared using a solution casting method. Then, the ratio of agar and banana powder also the concentrations of silver nitrate solution have affected the properties of biocomposite film. These physical properties were characterized by UV-Vis spectrophotometer and colorimeter. The results indicated that biocomposite film with the mass ratio of agar to banana = 3:1 (A₃B₁_Ag50) was brown and had the maximum absorption of UV-Vis light at 432 nm. This biocomposite film exhibited strong antibacterial activity against both Escherichia coli and Staphylococcus aureus. Because of their microbial activity and physical properties, these biocomposite films have the potential to be used extending the shelf life of food packaging.