Size Of Silver Nanoparticles Research Articles

Effects of silver nanoparticles prepared by aqueous extract of Ferula communis on the developing mouse embryo after maternal exposure.

Green synthesis of silver nanoparticles (AgNPs) from aqueous silver nitrate has been achieved using an extract of Ferula communis leaf as a capping, reducing, and stabilizing agent. The formation and stability of the green synthesized silver nanoparticles in the colloidal solution were monitored by absorption measurements. Silver nanoparticles were characterized by different analyses such as X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and FT-IR spectroscopy. The average particle size of silver nanoparticles was determined by high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) analyses. In this experiment, pregnant female mice were divided into four groups (G); G1 was the control and received phosphate-buffered saline, G2 received orally aqueous extract of F. communis leaf, G3 received orally AgNPs chemically prepared by NaBH4, and G4 received orally AgNPs prepared by aqueous extract of F. communis leaf. The diameter of AgNPs was 20nm. AgNPs exhibited good catalytic reduction ability toward methyl orange in the presence of sodium borohydride with a rate constant of 2.95 x 10-4 s-1. The results revealed the occurrence of resorbed embryos in G2, G3, and G4 with different percentages. The livers of mothers and embryos at E14.5 in G2, G3, and G4 showed different levels of histopathological alteration and increase in GFAP and CTGF expressions compared with the control group. The study concluded that the oral administration of small-sized AgNPs (20nm) prepared by Ferula extract had less toxicity than those prepared by the chemical method.

Green synthesis of aminated hyaluronic acid-based silver nanoparticles on modified titanium dioxide surface: Influence of size and chemical composition on their biological properties

This is the first report on an efficient, “environmentally friendly” chemical reduction method for the synthesis of aminated hyaluronic acid-based silver nanoparticles on the modified surface of titanium dioxide nanoparticles aimed for biological applications. Silver nanoparticles exhibit well-known physical-chemical and optical properties appropriate for different biological applications. Modifying the nanoparticles leads to a change in their expected bioactivity. This represents an important topic for the current research. We have developed a novel aminated hyaluronic acid (HA-EDA)-based protocol to obtain silver nanoparticles, in which HA-EDA was used for the first time as a reducing and stabilizing agent. The effect of the size of silver nanoparticles on the titanium dioxide surface and the chemical composition of the obtained materials were investigated by TEM, XRD, XPS, ATR-FTIR, Raman spectroscopy, NMR and H2-TPR analyses.The antioxidant, in vitro biocompatibility, and antimicrobial activity of the fabricated composites have been evaluated. The results prove that the prepared materials exhibit antimicrobial, antioxidant, and anti-inflammatory activity, thus providing protection against infection and supporting tissue regeneration, these two key effects being of paramount importance for promoting wound healing.

Small size silver nanoparticles loaded with glycoside rich portion of Boerhavia Diffusa Linn. promotes wound healing: in-silico and in-vivo studies.

Silver nanoparticles (Ag-NPs) are increasingly used in various fields, including medicine, owing to their unique physicochemical properties. Due to their smaller size, the contact with biological components is increased, and consequently, it performs better as an antibacterial and antimicrobial. In this study, the authors have focused on the synthesis of small-sized spherical silver nanoparticles (Ag-NPs) by a chemical reduction method using two different capping agents and concentrations of AgNO3 as a precursor. Additionally, various amounts of Glycoside Rich Portion (GRP) isolated from the roots of Boerhaavia diffusa L. were loaded onto synthesised Ag-NPs. Punarnavoside, a glycoside found in GRP, has been reported to have antifibrinolytic properties. The docking study of punarnavoside present in GRP has shown good binding affinity with various antifibrinolytic targets. The surface plasmon resonance band, particle size, polydispersity index, and zeta potential values have been used to analyse the interaction and kind of bonding between GRP and Ag-NPs. A batch of trisodium citrate (TSC)-capped Ag-NPs loaded with 0.1ml of 1% GRP solution showed particle size smaller than 50nm with a stable zeta potential value of -55.3mV. Fourier transform infrared spectroscopic results showed CO and C-O bonds in GRP interacted with Ag-NPs. A batch of TSC-capped GRP-loaded Ag-NPs (1%)-based gel was developed using carbopol as a polymer. The TSC-capped GRP-loaded silver nanogel had greater wound closure in rats, as observed during the histopathological studies in the excision wound model. The antifibrinolytic activity of GRP, when coupled with the antibacterial and bactericidal properties of silver, demonstrated an increased wound healing effect.

Synthesis of silver nanoparticles for use in conductive inks by chemical reduction method

In this study, the chemical reduction method was applied to synthesize silver nanoparticles used to prepare conductive inks. The two variables of polyvinylpyrrolidone (PVP)-stabilized mole in the 0.01–0.03 mol range and hydrazine reducing mole in the 0.1–0.5 mol range, along with constants such as precursor mole (silver nitrate), complexing mole (ethylene diamine) and solvent mole (water), were used. Nine random samples proposed by the Design Expert software were examined and studied. X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) were then used to characterize and evaluate the synthesized nanoparticles. According to the results obtained by XRD, FE-SEM and TEM analyses, the sample with 0.025 mol and 0.3 mol PVP had the minimum size of silver nanoparticles, which was around 20 nm, so it was chosen as the optimal sample for further research. The conductive ink was also prepared with the optimal sample of silver nanoparticles in 40% by weight and then characterized and evaluated by applying ultraviolet–visible (UV–Vis), simultaneous thermal analysis (STA), FE-SEM and electrical conductivity analysis. Finally, conductive ink was applied to polyethylene terephthalate (PET) and acrylonitrile butadiene styrene (ABS) substrates. The surface electrical resistance of conductive ink on PET and ABS substrates was then measured at about 6.4 Ω and 2.2 Ω, respectively.

Sodium titanate nanorods decorated with silver nanoparticles as a high-performance anode material for sodium-ion batteries

Sodium titanate (Na2Ti6O13) exhibits great potential as a sodium-ion batteries (SIBs) anode material, nevertheless the limited electronic conductivity markedly hampers its applications. To combat this shortcoming, carbon coating has been widely employed to fabricate Na2Ti6O13/C composites; however, this method requires a high-temperature processing that is energy-intensive releases environmental pollutants. Herein, silver is used as a novel conducting agent, and we demonstrated a simple and efficient method to prepare Ag@Na2Ti6O13 composites. We find that nano-sized silver particles (3%) are well distributed on the Na2Ti6O13 surface, leading to boosted conductivity of the composites. As a result, the Ag@Na2Ti6O13 electrode exhibits an excellent performance for Na+ insertion, where after 100 cycles a discharge capacity of 189 mAh g−1 is achieved, demonstrating superior capacity retention of 97.9%. The result of silver coating on the battery performance was investigated coherently by various techniques, such as electrochemical impedance spectroscopy. Our work provides a feasible approach to prepare electronically conductive compounds for battery applications.

Green synthesis of silver nanoparticles using Mentha crispa L. leaf extract for treatment of dye wastewater

Mentha crispa L. is one of Vietnam’s most precious folk medicines and is also a spice used in many delicious dishes in Vietnam and around the world. The use of Mentha crispa L. leaf extract as a reducing agent for Ag+ ions to synthesize silver nanoparticles is discussed in this paper. Single silver nanospheres were dispersed in biological media and their sizes were controlled in the range of 20-80 nm. Factors affecting particle size and shape such as extract concentration, AgNO3 concentration, reaction time, and temperature were investigated to determine the optimal parameters for particle synthesis. The optical properties, dispersion, crystal structure, morphology, and sizes of silver nanoparticles were investigated through UV-Vis absorption spectroscopy, dynamic light scattering (DLS) measurements, X-ray diffraction, and transmission electron microscopy (TEM). The functional groups on the L.AgNPs were determined by Fourier-transform infrared (FTIR) transmittance spectra. The synthesised silver nanoparticles were used to treat methylene blue (MB) dye, the main component of dye wastewater, based on their photocatalytic properties. The results show that in the presence of L.AgNPs, the photodegradation efficiency of NaBH4 or H2O2 reducing agents is much higher, up to 95% of illumination.

Photochemical Synthesis of Noble Metal Nanoparticles: Influence of Metal Salt Concentration on Size and Distribution.

This paper explores the photochemical synthesis of noble metal nanoparticles, specifically gold (Au) and silver (Ag) nanoparticles, using a one-component photoinitiator system. The synthesis process involves visible light irradiation at a wavelength of 419 nm and an intensity of 250 mW/cm2. The radical-generating capabilities of the photoinitiators were evaluated using electron spin resonance (ESR) spectroscopy. The main objective of this study was to investigate how the concentration of metal salts influences the size and distribution of the nanoparticles. Proposed mechanisms for the photochemical formation of nanoparticles through photoinitiated radicals were validated using cyclic voltammetry. The results showed that the concentration of AgNO3 significantly impacted the size of silver nanoparticles, with diameters ranging from 1 to 5 nm at 1 wt% and 3 wt% concentrations, while increasing the concentration to 5 wt% led to an increase in the diameter of silver nanoparticles to 16 nm. When HAuCl4 was used instead of AgNO3, it was found that the average diameters of gold nanoparticles synthesized using both photoinitiators at different concentrations ranged between 1 and 4 nm. The findings suggest that variations in HAuCl4 concentration have minimal impact on the size of gold nanoparticles. The photoproduction of AuNPs was shown to be thermodynamically favorable, with the reduction of HAuCl4 to Au0 having ∆G values of approximately -3.51 and -2.96 eV for photoinitiators A and B, respectively. Furthermore, the photoreduction of Ag+1 to Ag0 was demonstrated to be thermodynamically feasible, with ∆G values of approximately -3.459 and -2.91 eV for photoinitiators A and B, respectively, confirming the effectiveness of the new photoinitiators on the production of nanoparticles. The synthesis of nanoparticles was monitored using UV-vis absorption spectroscopy, and their sizes were determined through particle size analysis of transmission electron microscopy (TEM) images.

Silver Nanoparticles: Synthesis in Newly Formed Ternary Deep Eutectic Solvent Media, Characterization and their Antifungal Activity

Background: When halide salts and hydrogen bond donors are combined, they produce Deep Eutectic Solvents, which have a lower freezing/melting point than the individual components. At room temperature, they have emerged as viable alternatives to ionic liquids. The wonderful features of deep eutectic solvents such as humidity tolerance, high-temperature stability, low cost, non-hazardous, reusable, and recyclable nature, allow them to replace ionic liquids. Objective: To prepare two newer Ternary Deep Eutectic Solvents using Malonic acid - Glucose – Glutamine and Malonic acid - Fructose – Glutamine. Using the prepared ternary deep eutectic solvents, to synthesize silver nanoparticles and study the antifungal behavior. Methods: The ternary deep eutectic solvents were prepared by the evaporation method in water and subjected to measure the properties such as density, pH, conductivity, viscosity, and absorption frequencies of Fourier Transform Infrared Spectroscopy. The prepared deep eutectic solvents are used for the synthesis of Silver Nanoparticles by the chemical reduction method in presence of Hydrazine Hydrate as a reducing agent and sodium hydroxide as a stabilizing agent. The synthesized nanoparticles are characterized by UV-Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis techniques. Results: The characteristic absorption peak of UV-Visible Spectroscopy shows that silver nanoparticles were formed. FTIR exposes the metallic and other bonding of the nanoparticles and the caping materials. From the XRD pattern, we found the crystalline and the images formed in the SEM are in the nanoscale. The average particle size of silver nanoparticles is 116.87nm and 26.61 nm. Conclusion: In our study, two types of novel ternary deep eutectic solvents were developed. They act as a better solvent media for the synthesis of silver nanoparticles and the synthesized nanoparticles show antifungal behaviors against some fungi.

Influence of the Crystallographic Texture of ITO on the Electrodeposition of Silver Nanoparticles

Metal nanoparticles exhibit physical and chemical properties that differ significantly from macroscopic metal phases. In particular, silver nanoparticles (NPs) had have extensive attention since it has a strong interaction with light due to their high quality localized surface plasmon resonances, which can be tuned all across the visible to the NIR regime. These strong and tuneable interaction of visible light with silver NPs have found many applications, in sensing, surface enhanced Raman spectroscopy, photo(electro)catalysis, and more.Polycrystalline indium tin oxide (ITO) films are highly desired substrates for many of these optoelectronic applications. In many of these applications, it is essential to reliably and precisely control the size and density of silver NPs. Even though it is well known that the electrochemical control over nucleation and growth of silver NPs on foreign substrates highly depends on the surface properties of the substrate, yet, the only parameter that is often specified for these ITO substrates is a bulk property: sheet resistance. As a result, nucleation and growth on ITO is highly irreproducible.In this work, we show that ITO substrates with same technical specifications (i.e. sheet resistance, light transmittance and roughness) and supplier may still have different surface properties such as the crystalline texture. We find that these differences in the surface properties has a strong impact on the nucleation and growth. Even though we used seemingly equal ITO substrates, XRD and EBSD scans clearly differentiate between two types of films based on the ratio between the (222) and (400) related peaks. We controlled the density and size of the silver NPs by making use of the double pulse technique. In this method, where the high overpotential nucleation pulse controls the nucleation density. Previous studies have reported an empirical exponential relationship between island density and nucleation pulse overpotential, where the slope is a measure for the electron kinetics.We find that the preferential presence of lower index surfaces (e.g. (100)) leads to few orders of magnitude lower particle density compared to the preferential presence of higher index surfaces (e.g. (111)). Furthermore, the density on the lower index surface is strongly dependent on the nucleation pulse overpotential, while the higher index surface is barely affected. We find that this difference in the relationship is caused by mass transport limited nucleation. We have verified this through a spatial correlation analysis using the nearest-neighbour distance. For higher index surfaces, the nucleation density is already large compared to the Nernst diffusion length at low nucleation pulse overpotentials, such that the limiting mechanism becomes mass transport instead of electron kinetics. We therefore elucidate that the empirical exponential relationship between island density and nucleation pulse overpotential is not enough to draw conclusions on electrode kinetics, where additional validation of the growth process is essential.Beyond careful control of electrochemical parameters, here we show that neglecting the macroscopic surface characteristics of polycrystalline substrates can lead to major ambiguity in nucleation and growth dynamics of metal nanoparticles. We show here that XRD characterization prior to deposition is a simple additional measure to tailor metal nanoparticle electrochemical growth on ITO.

Comparative study of microscale and macroscale technique for encapsulation of Calotropis gigantea extract in metal-conjugated nanomatrices for invasive ductal carcinoma

The encapsulation of plant extract in nanomatrices has limitations due to its adhesion to walls, size control, high cost and long durations that results in low yield. Macroscale and microscale level techniques for development of micro/nanoparticles may impact the encapsulation of plant extract. This study aimed to evaluate the relative efficiency of microscale and macroscale techniques for encapsulation of plant extract, which is not compared yet. Keeping this in view, encapsulation of Calotropis gigantea leaves extract (CaG) was attained in silver-conjugated poliglusam nanomatrices (POL/Ag) to induce apoptosis in invasive ductal carcinoma (IDC) cells. The ethanolic CaG extract was prepared using percolation method and characterized by chemical tests for its active phytochemical compounds. The droplet-based microfluidic system was utilized as microscale encapsulation technique for CaG in nanomatrices at two different aqueous to oil flow rate ratios 1.0:1.5, and 1.0:3.0. Moreover, conventional batch system was utilized as macroscale encapsulation technique consisted of hot plate magnetic stirrer. The prepared nanomatrices were analysed for antioxidant activity using DPPH test and for cytotoxicity analysis using MCF-7 cells. The characteristic peaks of UV–Vis, FTIR and XRD spectrum confirmed the synthesis of CaG(POL/Ag) by both the encapsulation methods. However, microfluidic system was found to be more expedient because of attaining small and uniform sized silver nanoparticles (92 ± 19 nm) at high flow rate and achieving high encapsulation efficiency (80.25%) as compared to the conventional batch method (52.5%). CaG(POL/Ag) nanomatrices found to have significant antioxidant activity (p = 0.0014) against DPPH radical scavenging activity. The CaG(POL/Ag) of the smallest sized formulated by the microfluidic system has also shown the highest cytotoxicity (90%) as compared to batch method (70%) at 80 µg/mL. Our results indicate that the microscale technique using microfluidic system is a more efficient method to formulate size-controlled CaG(POL/Ag) nanomatrices and achieve high encapsulation of plant extract. Additionally, CaG(Pol/Ag) was found to be an efficient new combination for inducing potent (p < 0.0001) apoptosis in IDC cells. Therefore, CaG(Pol/Ag) can be further tested as an anti-cancer agent for in-vivo experiments.

Systematic Photophysical Interaction Studies Between Newly Synthesised Oxazole Derivatives and Silver Nanoparticles: Experimental and DFT Approach.

In this study, the photophysical properties of oxazole derivatives such as 5-(furan-2-yl) -4-tosyloxazole (OX-1) and 5-(2-bromothiazol-4-yl)-4-tosyloxazoles (OX-2) were investigated using theoretical and experimental techniques. The ground and excited state dipole moments were empirically obtained utilising the solvatochromic shift technique and several solvatochromic correlations such as Lippert's, Bakhshiev's, KawskiChamma- Viallet's, and solvent polarity equations. The ground state dipole moments, HOMO-LUMO and molecule electrostatic potential map were also computed using ab initio calculations and evaluated using Gaussian 09 W software. Furthermore, spectroscopic interactions between newly synthesised dyes (OX-1 and OX-2) and freshly synthesised silver nanoparticles (size 40nm) were studied. Increased absorbance and widening of absorption spectra for both dyes in the presence of varied quantities of silver nanoparticles show the potential of dye-nanoparticle interactions. Fluorescence quenching has been detected for both dyes in the presence of colloidal silver nanoparticles, indicating dynamic quenching, and a significant overlap between the absorption and emission spectra of the silver nanoparticle reveals that fluorescence quenching is also due to energy transfer.

Photoinduced edge-specific nanoparticle decoration of two-dimensional tungsten diselenide nanoribbons

Metallic nanoparticles are widely explored for boosting light-matter coupling, optoelectronic response, and improving photocatalytic performance of two-dimensional (2D) materials. However, the target area is restricted to either top or bottom of the 2D flakes. Here, we introduce an approach for edge-specific nanoparticle decoration via light-assisted reduction of silver ions and merging of silver seeds. We observe arrays of the self-limited in size silver nanoparticles along tungsten diselenide WSe2 nanoribbon edges. The density of nanoparticles is tunable by adjusting the laser fluence. Scanning electron microscopy, atomic force microscopy, and Raman spectroscopy are used to investigate the size, distribution, and photo-response of the deposited plasmonic nanoparticles on the quasi-one-dimensional nanoribbons. We report an on-surface synthesis path for creating mixed-dimensional heterostructures and heterojunctions with potential applications in opto-electronics, plasmonics, and catalysis, offering improved light matter coupling, optoelectronics response, and photocatalytic performance of 2D materials.

Controlled release of Ag+ ions to human cancer cells selectively neutralized with silver nanoparticles of different sizes produced by a green synthesis method

We present a facile green method to synthesize silver nanoparticles (AgNPs) with different sizes and uniform size distributions using an extract of Rhododendron mucronulatum flowers. Here, AgNPs were utilized to modify the release of Ag+ ions and selectively annihilate human cancer cells. AgNPs were prepared at ambient temperature (RT-AgNPs) and in higher-temperature water baths at 60 °C (W60-AgNPs) and 70 °C (W70-AgNPs) to modify the diameter and uniformity of the AgNPs. The W60-AgNPs were further treated with acid to modify their size and surface state (named AW60-AgNPs). The water-bath technique enabled an alteration of the relative rates of initial nucleation and growth of nanoparticles in a homogeneous environment, promoting the creation of small AgNPs with a uniform diameter distribution. The acid treatment eroded the surface particles to reduce their diameter and simultaneously introduced functional groups. The Ag+-ion release efficiency of the prepared nanoparticles and the toxicity of Ag+ ions on cancer cells were examined. Among the prepared samples, the AW60-AgNPs released the greatest amount of Ag+ ions and produced the largest amount of reactive oxygen species (O2̇−, ˙OH, and H2O2). All of the AgNP samples were applied to tumor cells (K562 and HT1080) and healthy cells (LO2) in vitro. In the presence of K562 cells, AW60-AgNPs showed the most efficient dose- and time-dependent early and late apoptosis as well as reduced viability. A crystal violet assay showed that the synthesized particles preferentially attack HT1080 cancer cells rather than LO2 normal cells. We found that Ag+ ions release efficiency and selectivity varied with particle size, and that DNA damage in tumor cells was due to the formation of Ag+-coordinated complexes within DNA base pairs.

In-situ formation of Azo dye capped-silver nanoparticles and their nanocomposite with reduced graphene oxide for dye degradation

This work entails a novel and simple chemical method for preparation of silver and reduced graphene oxide nanocomposite (Ag@rGO NCs). In nanocomposite fabrication, the silver salt was reduced through Eriochrome Black T (EBT) and Methylene Orange (MO) respectively in the presence of graphene oxide. The mechanism of interaction was understood by simulating the system using first-principle Density Functional Theory approach. The formation of silver nanoparticles was confirmed through UV–visible spectroscopy by observing the plasmonic peak. By X-Ray Diffraction (XRD) analysis, the crystallite size of silver nanoparticles was calculated to be 9.83 nm and 12.5 nm respectively, for two nanocomposites. Statistically, spherical surface morphology and average particles diameter of silver was assessed to be 38 nm and 42 nm from scanning electron microscopy (SEM) analysis. Energy dispersive spectroscopy (EDS) confirmed the presence of silver in the nanocomposites. Fourier Transform Infrared (FTIR) and RAMAN Spectroscopy confirmed the interaction mechanism of GO and Ag NPs by changes in surface groups. In photocatalysis, the dye degradation efficiency of Ag@rGO NCs have been studied against Methylene Blue (MB) and found to be 69.7% and 87.9% approximately.

Effects of silver nanoparticles on seed germination and growth performance of pea (Pisum sativum)

Agricultural biotechnology has become familiar with nanomaterials' properties and potential use. The present experiment was conducted to examine the effect of 8.1 ± 1.6 nm sized silver nanoparticles (AgNPs) on the growth performance and yield quality of pea (Pisum sativum) as well as Arbuscular Mycorrhizal Fungi (AMF) and Rhizobium population in the soil. Pea seeds were separately treated in 3 h with 1 mM, 2.5 mM, and 5 mM of AgNPs aqueous solution, and after 2 weeks their effect on seed germination, leaf number, shoot, and root length, shoot and root dry weight, fresh biomass, and dry biomass weight were investigated in laboratory condition using Murashige and Skoog (MS) Basal Medium. Results showed that 2.5 mM AgNPs had a significant positive impact and notably increased all the experimental growth parameters mentioned above of pea compared with the control. The experiment was also conducted in an open environment under a natural condition where 2.5 mM AgNPs improved 31.57 % weight of fruit and 9.09 % of seed weight without causing any harm to the symbiotic microbes (AMF and Rhizobium bacteria). Whereas, the other concentrations of nanoparticles (1.0 mM and 5.0 mM) showed varied impacts on the germination, growth, and yield of pea in comparison with the control. For the first time, the outcome demonstrated the successful use of 2.5 mM AgNPs in enhancing the growth and yield of peas, and increased AMF colonization but showed no impact on Rhizobium compared to the control.

Comparative Synthesis of Silver Nanoparticles: Evaluation of Chemical Reduction Procedures, AFM and DLS Size Analysis.

The size of silver nanoparticles plays a crucial role in their ultimate application in the medical and industrial fields, as their efficacy is enhanced by decreasing dimensions. This study presents two chemical synthesis procedures for obtaining silver particles and compares the results to a commercially available Ag-based product. The first procedure involves laboratory-based chemical reduction using D-glucose (C6H12O6) and NaOH as reducing agents, while the second approach utilizes trisodium citrate dehydrate (C6H5Na3O7·2H2O, TSC). The Ag nanoparticle suspensions were examined using FT-IR and UV-VIS spectroscopy, which indicated the formation of Ag particles. The dimensional properties were investigated using Atomic Force Microscopy (AFM) and confirmed by Dynamic Light Scattering (DLS). The results showed particle size from microparticles to nanoparticles, with a particle size of approximately 60 nm observed for the laboratory-based TSC synthesis approach.

In silico and in vitro antimicrobial activity of date-palm aided silver nanoparticles conjugated with drug ampicillin for drug release study

Pathogenic bacteria, viruses, fungi, and other parasites are the primary cause of infectious diseases. According to the World Health Organization, drug resistance will cause 10 million deaths from pathogenic infectious diseases by 2050. Antibiotics are being developed to eradicate infectious microorganisms. Continuous drug use, over time, increases drug-resistant bacteria and endangers human health. As a result, advancements in nanotechnology promise to improve the resolution of drug resistance. Nanoparticles encapsulated with antibiotic drugs are currently used as nanocarriers to eradicate bacteria and increase bioavailability. This study used microwave irradiation to create silver nanoparticles from date palm seed and leaf extract. Ultraviolet–visible spectrophotometry was used to confirm the silver nanoparticle synthesis, revealing surface plasma resonance at 420 and 370 nm. The silver nanoparticles were conjugated with the antibiotic drug ampicillin to improve bioavailability. The X-ray diffraction pattern confirms the formation of the crystalline nature of silver nanoparticles. The spherical morphology and size of silver nanoparticles were revealed using field emission scanning electron microscope (50–70 nm) and transmission electron microscopy (14–26 nm). The in vitro antimicrobial activity of silver nanocomposites shows the good zone of inhibition against the microorganisms such as Escherichia coli, Staphylococcus aureus, Aspergillus flavus, and Aspergillus niger, respectively. In addition, in silico molecular docking study was carried out for the twenty biomolecules of date palm. Among them, the compound tricosanoic acid have a good binding affinity (−233.43 kcal/mol) against Salmonella typhi compared with standard ampicillin (−205.76 kcal/mol). As a result, the current study contributes to use the drug-conjugated nanosilver particles which improve the efficacy against microbial pathogens.

Ag triangle nanoplates assembled on PVC/SEBS membrane as flexible SERS substrates for skin cortisol sensing

Surface-enhanced Raman scattering (SERS) based on rigid substrates has been widely used in biomedical detection due to its high sensitivity and specificity. However, the tedious operation steps for preparing SERS rigid substrates limited their applications in real-world detection. Compared with general rigid substrate, the flexible substrate has the advantages of simple preparation and easy portability, which are suitable for rapid, wearable and personalized detection in the field of point-of-care test. Herein, the flexible SERS substrates employing copolymer were fabricated and used for detection of skin cortisol, a biomarker for evaluating psychological stress in sweat. Silver triangle nanoplates with sharp corner were used as enhanced particles, and transferred to polyvinyl chloride/styrene-ethylene-butene-styrene copolymer (PVC/SEBS) film through three-phase interface self-assembly. By adjusting the size of silver nanoparticles, the ratio of PVC to SEBS in the polymer film, and the number of transfers of self-assembled silver films, the enhancement effect of the flexible SERS substrate was maximized. In addition, functionalization of the flexible SERS substrate with cortisol antibodies is used to achieve specific detection of cortisol on the skin surface. Under the optimal conditions, the Raman peak intensities at 1268 and 1500 cm−1 of the cortisol had a good linear relationship with the logarithm of its concentration in the range of 10−7 to 10−3 M, and the detection limits were 5.47 × 10−8 M and 5.51 × 10−8 M, respectively. The flexible silver triangle nanoplates SERS substrate constructed by self-assembly in the three-phase interface has the characteristics of good specificity and high sensitivity, which has potential for transdermal cortisol wearable detection, providing a feasible method for the rapid evaluating psychological stress level.

Three in-one fenestrated approaches of yolk-shell, silver-silica nanoparticles: A comparative study of antibacterial, antifungal and anti-cancerous applications

Yolk-shell-based silica-coated silver nanoparticles are prominently used in the biomedical field aas well as bare silver nanoparticles for various biological applications. The present work narrates the synthesis and silica coating of metallic silver nanoparticles and investigates their antibacterial, antifungal, and anticancerous activity. Both synthesized nanoparticles were characterized by TEM, and SEM-EDX. The average size of silver nanoparticles was 50 nm, while after coating with silica, the average size of silica-coated silver nanoparticles was 80 nm. The nanoparticles' antibacterial, antifungal, and anticancer properties were comparatively examined in vitro. Agar well diffusion method was employed to explore the antibacterial activity against gram-positive bacteria (Bacillus cereus) and gram-negative bacteria (Escherichia coli) at different concentrations and antifungal activity against Candida Albicans. To understand the minimum concentration of both nanoparticles, we employed the minimum inhibitory concentration (MIC) test, against bacterial and fungal strains, which was dose dependent. We learned that bare silver nanoparticles showed high antibacterial activity, whereas silica-coated silver nanoparticles surpassed their antifungal capability over bare silver nanoparticles against Candida albicans. The anticancer activity of the as-prepared nanoparticles was executed in opposition to the prostate cancer cell (PC-3) line by MTT assay, which showed meaningful activity. Following this, flow cytometry was also effectuated to learn about the number of apoptotic and necrotic cells. The results of this study demonstrate the dynamic anti-cancerous, antibacterial, and antifungal activities of bare silver nanoparticles and silica-coated silver nanoparticles for a long-lasting period.

Preparation, Characterization, and Antibacterial Activity of Silver Nanoparticle-Decorated Ordered Mesoporous Carbon

In this study, Ordered Mesoporous Carbon (OMC) was prepared using resol as a carbon precursor and F127 as a soft template. Small-angle X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) images, and nitrogen adsorption and desorption isotherms revealed that OMC possessed ordered hexagonal mesostructures (p6m) with an ordered pore size of 3.2nm, a high specific surface area (SBET) of 539m2/g, and a large total pore volume (Vtotal) of 0.44cm3/g. Subsequently, silver nanoparticles synthesized from an aqueous AgNO3 solution using glucose as a reducing agent and starch as a stabilizing agent were decorated on OMC, producing Ag/OMC. XRD analysis revealed that the composite contained silver crystals. In addition, the content and size of silver nanoparticles in Ag/OMC were 0.71wt% (AAS) and around 25-50nm (TEM), respectively. Due to the surface cover of silver nanoparticles, SBET and Vtotal of Ag/OMC slightly decreased to 417m2/g and 0.38cm3/g, respectively. Both agar and broth dilution techniques were used to evaluate the antibacterial activity of the material against Staphylococcus aureus. Ag/OMC with a Minimum Inhibitory Concentration (MIC) of 25.0μg/mL is a potential candidate for use against Staphylococcus aureus.