Formation Of Silver Nanoparticles Research Articles

SILVER NANOPARTICLES-AQUEOUS LEAF EXTRACT OF SIDAGURI (SIDA RHOMBIFOLIA) AS REDUCING AGENTS

The Sidaguri leaf, scientifically known as Sida rhombifolia, is a plant species rich in flavonoids that have the ability to act as reducing agent in formation of silver nanoparticles. This study presented the synthesis of silver nanoparticles (AgNp-Sid) using aqueous leaf extract of sidaguri. This study utilized a concentration ratio of 2:90 mL aqueous leaf extract of Sidaguri and AgNO3 1 mM. The size and morphology of AgNp-Sid was measured using UV-Visible Spectrophotometer, PSA, FT-IR, SEM-EDS, and XRD. The investigation revealed an ordinary particle size of 63.5 nm with polydispersity index (PI) of 0.284. The maximum wavelength varies between 405.4 nm and 407.8 nm with the increasing of time. AgNp-Sid exhibited a spherical morphology and had a crystalline structure that is face-centered cubic. The results suggested that the aqueous leaf extract of sidaguri had the ability to function as a reducing agent in the synthesis of silver nanoparticles, offering a safe, cost-effective, and environmentally friendly alternative.

Effect of Environmental Factors on The Production of Silver Nanoparticles by Yeast Strains

In the presented work, the literature data on the influence of various environmental factors were analyzed on the formation of silver nanoparticles by yeast strains. It was determined that the optimal conditions for the synthesis of silver nanoparticles by the yeast strain Saccharomyces ellipsoideus BSU-XR1 were on the 21st day of incubation, on 4-6 days of incubation in different strains of Saccharomyces cerevisiae, and between 2-10 days in Candida strains. The optimal amount of wet biomass was between 8 and 10 g for Candida strains and 10 g for Saccharomyces strains. The temperature limit for Saccharomyces was observed at 25-35°C, and for Candida at 25-37°C. For strains, synthesis of silver nanoparticles was optimal in the pH range of 4-10, and pH range of 7 for Candida strains. Depending on the concentration of AgN03 salt, the optimal synthesis of silver nanoparticles occurred at concentrations of 0.5 and 1 mM for Saccharomyces, and 1 mM for Candida. The optimal incubation conditions for both sexes were under dark environment.

Electrospun poly(N-vinylpyrrolidone) membranes with Ag nanoparticles for wound dressings: Production and characterization

Wound dressings have long been used to promote the healing of skin injuries. In the work reported here, fibrous membranes were produced by electrospinning poly(N-vinylpyrrolidone) (PVP) solutions containing silver nitrate at varying mass ratios (1:200, 1:100 and 1:50 AgNO3:PVP). PVP solutions without AgNO3 were used as a control. The electrospun membranes were irradiated using 254 nm UV light to simultaneously photo-crosslink PVP and promote the formation of silver nanoparticles (AgNPs). The formation of AgNPs was confirmed by scanning electron microscopy and transmission electron microscopy, as well as by detecting the surface plasmon resonance peak at 420 nm in the UV–Vis spectrum during release studies. The swelling rate of fibrous membranes was lower for those containing AgNPs compared to PVP-only membranes. The Kirby-Bauer diffusion test performed against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans showed that all AgNPs-containing membranes exhibited an inhibitory effect on all microorganisms tested. The in vitro cytotoxicity assay showed that membranes with lower silver concentration were less cytotoxic. This study presents a simple route to producing a wound dressing with antimicrobial action that has a swelling behavior capable of absorbing exudates, provides controlled release of silver and has low cytotoxicity.

Solution plasma synthesis of nitrogen-doped carbon dots from glucosamines: Comparative fluorescence modulation for dopamine detection

The intriguing fluorescence characteristics of carbon dots (CDs) have led to many sensor applications, particularly for dopamine (DA), a molecule linked to various diseases. This study prepares CDs from glucose and glucosamine (nitrogen-free and nitrogen-containing precursors) using a simple solution plasma process (SPP). We explore how nitrogen elements and counterions in glucosamine (hydrochloride and sulfate) affect CD properties and their ability to modulate fluorescence for DA detection. Glucosamine offers three advantages over glucose: (i) single-step CD synthesis via SPP, (ii) enhanced fluorescence of CDs, and (iii) improved fluorescence response to DA. We investigate the DA detection capabilities of N,S-CDs (from glucosamine sulfate) and N,Cl-CDs (from glucosamine hydrochloride). Both can sense DA with distinct photoluminescence responses. N,S-CDs show selectivity and fluorescence brightening upon DA interaction, with a detection limit of 33.05 μM. N,Cl-CDs demonstrate higher sensitivity with a lower detection limit of 0.1212 μM through fluorescence quenching. Silver ions (Ag+) may also contribute to N,Cl-CDs quenching; however, the observed color change to gray due to silver nanoparticle (AgNP) formation helps pinpoint the quenching substance. The varied photoluminescence responses arise from different surface functional groups: N,S-CDs have amino-rich surfaces, while N,Cl-CDs have conjugated carbonyl-rich surfaces. This study illustrates the mechanisms of DA detection and AgNP formation, suggesting the potential of CDs in medical diagnostics as selective tools for disease diagnosis. Additionally, we compare the DA sensing methodology of our CDs with existing literature, highlighting the advantages of our sensor.

Non-enzymatic Determination of Glucose in Artificial Urine Using 3D-µPADs through Silver Nanoparticles Formation

Patients with diabetes often experience blood glucose fluctuations, making monitoring crucial. Traditional blood sampling methods pose risks of infection and pain. An alternative non-invasive approach using urine tests has been explored. Recent studies highlight microfluidic paper-based analytical devices (µPADs) as convenient, simple, and easily fabricated tools for non-invasive glucose measurement. This study aims to develop a concept of measuring glucose in artificial urine using 3D-µPADs in a non-enzymatic manner by utilizing glucose as a reducing agent for silver nanoparticle (AgNPs) formation. Embedding three-dimensional connectors in µPADs links the sample and detection zones to limit reagent mixing and improve glucose detection resolution. The optimal conditions were NaOH 10 M, starch 1%, and AgNO3 30 mM, with sample and detection zone volumes of 10 and 9 µL, respectively. The fifth reaction sequence involved AgNO3 in the detection zone and a solution of glucose, NaOH, and starch in the sample zone at 1:1:1 volume ratio. The reagent drying time was 15 min, with immobilization once and reaction time of 9 min. The method showed excellent linearity (R2 = 0.9905), precision (%RSD = 4.27%), accuracy (77.32–92.58%), and limit of detection (11.11 mg/dL).

Zinc oxide (ZnO) Enhanced with Silver (Ag) is Used to Improve the Photocatalytic Degradation of Phenol in Aqueous Solutions

Silver-modified zinc oxide (Ag/ZnO) photocatalysts were synthesized and characterized to evaluate their efficiency in degrading phenol under UV irradiation. X-ray fluorescence, surface area analysis, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-visible reflectance spectroscopy confirmed successful deposition of metallic silver (Ag0) nanoparticles on the ZnO surface. The abundance of silver particles correlated directly with Ag concentration. Surface plasmon resonance bands indicated silver nanoparticle formation. Photocatalytic testing showed increased phenol degradation with Ag/ZnO versus pure ZnO, with 0.88 wt% Ag being optimal. Further experiments found 50 mg/L initial phenol and 0.15 g/L photocatalyst dosage optimized performance. Finally, almost complete elimination of phenol from drinking wastewater occurred after 180 minutes with the enhanced Ag/ZnO photocatalyst under UV irradiation.

Chitosan Coupled Silver Nanoparticles Electrocatalyst Synthesis and Characterization

This study sought to find a suitable technique for synthesizing and characterizing silver nanoparticles due to its applications in various fields such as nanotechnology and medical. The synthesized silver nanoparticles were characterized using SEM microscopy, FT-IR and UV-Vis spectroscopy. The maximum absorbance from the UV-Vis spectrophotometer showed the formation of silver nanoparticles with λ max of 418 nm. The FTIR analysis envisaged a strong symmetrical stretching at 1400 cm-1 to 1200 cm-1 with the major peaks recorded at 1390 cm-1 and 1380 cm-1, indicating the presence of nitro components in the sample. The signal at 1658 cm−1 corresponded to the amide (C=O) bonds stretching vibrations, at 1089 cm−1 C-O-C bonds and at 564 cm−1 plane with bends NH, plane-out and bends C−O. C-H stretching vibrational signal was noted at 2927 cm−1, and a broader band at 3426 cm−1 with an overlap between the O−H stretching vibration and N−H stretching vibration of the oligosaccharide applied in the capping. The concentration of chitosan on transmittance was done using 0.5%, 1.0%, 1.5% and 2.0% solutions with the results from FT-IR showing elaborate intensity at 2.0 % chitosan capping and the least at 0.5 %. Scanning microscope validated characterized silver nanoparticles morphology at 500nm. The results obtained from SEM depicted a size range of 100 nm with resolutions between 0.5 to 4 nm

PH‐responsive bionanocomposite pectin grafted with dimethylaminoethyl methacrylate and acrylic acid copolymer along with silver nanoparticles for breast cancer drug delivery

AbstractIn this study, we developed a pH‐responsive hydrogel membrane composed of pectin, dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) through a free radical‐triggered graft copolymerization method. Freshly formed silver nanoparticles (AgNPs) produced from the reduction reaction were embedded in the produced hydrogel. Pectin‐grafted dimethylaminoethyl methacrylate and acrylic acid copolymer [poly (DMAEMA‐co‐AA)‐g‐pectin] and its bionanocomposite with AgNPs were confirmed by Fourier‐transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The swelling behavior of poly (DMAEMA‐co‐AA)‐g‐pectin in solutions with diverse pH values was assessed. For use as a controlled drug delivery agent, the hydrogel was loaded with 5‐fluorouracil (5‐FU). The incorporation of AgNPs had a great impact on the entrapment efficiency of 5‐FU. At pH 7.4, nearly 48% of the 5‐FU was released in vitro from the polymeric nanocomposite within 24 h. Moreover, poly (DMAEMA‐co‐AA)‐g‐pectin and poly (DMAEMA‐co‐AA)‐g‐pectin/AgNPs presented high cytocompatibility toward normal skin fibroblast cells (BJ1), and the drug delivery system strongly inhibited human Caucasian breast adenocarcinoma cells (MCF‐7). These results demonstrated that these poly (DMAEMA‐co‐AA)‐g‐pectin/AgNPs are an excellent candidate for use in anticancer drug delivery systems.Highlights Free radical polymerization of nanocomposites incorporated with nanoparticles. Nanoparticles improve the bionanocomposites' drug loading. The developed bionanocomposites exhibit control drug release. The novel bionanocomposites acts as an excellent anticancer drug carrier.

Exploring the effects of cellulose sources on silver reduction and the bacterial removal of nanocellulose-based hydrogel beads

With water access challenged, there is a need to develop efficient and sustainable alternatives for water purification. Here, cellulose nanofibrils (CNFs) isolated from three source materials (softwood, soybean hulls and oat straw) were compared for the generation of hydrogels beads, and compared as support and reducing agent for silver nanoparticles formation. The silver-functionalized hydrogel beads (Ag-CNFs) were characterized, and the surface energy and specific surface area were evaluated. Antimicrobial testing was conducted to assess the efficacy of the Ag-CNFs against E. coli. The results showed that the Ag-CNFs had a higher specific surface area and lower surface energy compared with unmodified CNFs. Softwood-based Ag-CNFs exhibited the highest silver content and specific surface area, while the soybean hull based showed the highest hydrophobic character. The silver-functionalized soybean hull beads (Ag-sbCNF) showed the highest efficacy in reducing the growth of bacteria. Overall, this study highlights the potential of silver-functionalized CNFs hydrogel beads as a promising environmentally friendly and sustainable material for water filtration and disinfection. The findings also suggest that lower surface energy of the Ag-CNFs play an important role in their antimicrobial effect on tested water by enabling shorter retention, providing useful insights into the design of future water filtration materials.

Biofilm inhibition of Staphylococcus aureus by silver nanoparticles derived from Hellenia speciosa rhizome extract

Staphylococcus aureus is the most common cause of serious health conditions because of the formation of biofilm, which lowers antibiotic efficacy and enhances infection transmission and tenacious behavior. This bacteria is a major threat to the worldwide healthcare system. Silver nanoparticles have strong antibacterial characteristics and emerged as a possible alternative. This work is most relevant since it investigates the parameters influencing the biogenic nanoparticle-assisted control of bacterial biofilms by Staphylococcus aureus.Nanoparticles were fabricated utilizing Hellenia speciosa rhizome extracts, which largely comprised physiologically active components such as spirost-5-en-3-yl acetate, thymol, stigmasterol, and diosgenin, enhanced with the creation of silver nanocomposites. GC-MS, XRD, DLS, SEM, EDX, FTIR and TEM were used to investigate the characteristics of nanoparticles. The microtiter plate experiment showed that nanoparticles destroyed biofilms by up to 92.41 % at doses that ranged from 0 to 25 μg/ml. Fluorescence microscopy and SEM demonstrated the nanoparticles' capacity to prevent bacterial surface adhesion. EDX research revealed that the organic extract efficiently formed silver nanoparticles with considerable oxygen incorporation, which was attributed to phytochemicals that stabilize AgNPs and prevent accumulation. FTIR spectroscopy indicated the existence of hydroxyl, carbonyl, and carboxylate groups, which are essential for nanoparticle stability. TEM revealed that the AgNPs were spheroidal, with diameters ranging from 40 to 60 nm and an average of 46 nm. These results demonstrate the efficacy of H. speciosa extract in creating stable, well-defined AgNPs suited for a variety of applications. This work underlines the potential of green-synthesized AgNPs in biomedical applications, notably in the treatment of S. aureus biofilm-associated illnesses. The thorough characterization gives important information on the stability and efficiency of these biogenic nanoparticles.

Synthesis and Characterization of Silver Nanoparticles Stabilized with Biosurfactant and Application as an Antimicrobial Agent.

Surfactants can be used as nanoparticle stabilizing agents. However, since synthetic surfactants are not economically viable and environmentally friendly, biosurfactants are emerging as a green alternative for the synthesis and stabilization of nanoparticles. Nanoparticles have been applied in several areas of industry, such as the production of biomedical and therapeutic components, packaging coating, solar energy generation and transmission and distribution of electrical energy, among others. The aim of this study was to synthesize, in a simple and green way, silver nanoparticles (AgNPs) using the biosurfactant produced by Candida lipolytica UCP 0899 as a stabilizer. AgNPs were examined and morphologically characterized using the techniques of ultraviolet-visible spectroscopy (UV-visible), scanning electron microscopy (SEM), zeta potential and energy dispersive X-ray spectroscopy (EDS). Newly formed silver nanoparticles showed a maximum UV-visible absorption peak at 400 nm, while a shift to 410 nm was observed in those stored for 120 days. SEM micrograph confirmed the formation of nanoparticles with an average size of 20 nm and with a predominant spherical structure, while a zeta potential of -60 mV suggested that the use of the biosurfactant promoted their stability. Stabilized nanoparticles were tested for their antimicrobial activity against bacterial isolates of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Enterobacter sp., as well as fungal isolates of Candida albicans and Aspergillus niger. At a concentration of 16.50 µg/mL, AgNPs inhibited the growth of all target microorganisms according to the following decreasing order: E. coli (95%), S. aureus, C. albicans (90%), A. niger (85%), Enterobacter sp. (75%) and P. aeruginosa (71%). These results suggest the potential use of the biosurfactant as a stabilizer of silver nanoparticles as an antimicrobial agent in different industrial sectors. Furthermore, the in vivo toxicity potential of biosurfactants was evaluated using the Tenebrio molitor model. The larvae were treated with concentrations in the range of 2.5, 5.0 and 10 g/L, and no mortality was observed within the 24 to 72 h period, demonstrating non-toxicity within the tested concentration range. These findings support the safety, efficacy and non-toxicity of biosurfactant-stabilized nanoparticles.

Characterization of Silver Nanoparticles Synthesized With Fungi Isolated From Cocoa and Orange Plantation Soils

Green synthesis of nanoparticles with various metals is being interested among researchers globally attention for due to their safety, environmental friendliness and non-toxicity in contrast to chemical synthesis. Here, fungi were isolated from rhizosphere of cocoa and orange obtained from Federal University of Technology, Akure using standard mycological techniques with the aim of synthesizing silver nanoparticles. The silver nanoparticles synthesized by these fungal isolates were characterized using Ultraviolet-Visible (UV-Vis) and Fourier Transmission Infra- Red (FTIR) spectroscopy. Seven fungi isolated from the soil samples viz. Nigrospora sphaerica, Penicillium discolor, P. digitatum, Neurospora crassa, Alternarium infectoria, Trichophyton verrucosum and Mucor mucedo. The colour transformation from yellow to brown indicated the formation of silver nanoparticles. All the isolates showed an intense peak in the wavelength range of 410-440 nm. The FTIR analysis of silver nanoparticles synthesized by N. sphaerica, P. discolor, P. digitatum, N. crassa, A. infectoria, T. verrucosum and M. mucedo revealed the existence of a band at different stretches of bonds at different peaks of 3314.36 cm-1, 3310.47 cm-1, 2412.22 cm-1, 3912.33 cm-1 3614.52 cm-1, 3852.11 cm-1 and 2112.11 cm-1, respectively. The silver nanoparticles synthesized could have the potential application in agricultural, pharmaceutical and food industries as well as petrochemical industries for the clean - up of crude oil contaminated soils. J. Bio-Sci. 32(2): 31-44, 2024

Eco-friendly synthesis and antibacterial potential of chitosan crosslinked-EDTA silver nanocomposite (CCESN)

This study presents a novel and eco-friendly approach for synthesizing silver nanocomposite at room temperature. The method utilizes chitosan derived from snail (Archachatina marginata) shell waste crosslinked with EDTA as a combined reducing and capping agent. The existence of silver nanoparticles in the composite was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), energy dispersive X-ray (EDX), energy dispersive X-ray fluorescence (EDXRF) and thermogravimetric analysis (TGA). The TEM, SEM, XRD, and analyses revealed that the silver nanoparticle has a face-centered cubic structure with an average size of 45.30 nm respectively. EDX and EDXRF showed characteristic silver peaks confirming the formation of silver nanoparticles in the composite while TGA indicated that silver nanoparticles contributed to good thermal stability of the composite. The formation of silver nanoparticles was indicated by a brown color transformation and an ultraviolet visible (UV Vis) absorption peak at 435 nm. The synthesized nanocomposite demonstrated promising antibacterial activity against both Staphylococcus saprophyticus DSM 18669 and Escherichia coli O157 strains, with S. saprophyticus showing higher susceptibility. This highlights the potential of chitosan-EDTA silver nanocomposites as alternative antimicrobial agents.

A fluorimetric and colorimetric dual-mode sensor based on N, S co-doped carbon dots functionalized silver nanoparticles for glucose detection

A fluorescent-colorimetric dual-signal platform, N, S co-doped carbon dots functionalized silver nanoparticles (NS-CDs-AgNPs), was designed in situ by reducing AgNO3 in the presence of N, S co-doped carbon dots (NS-CDs) under the assistance of microwave irradiation for glucose determination. With the formation of silver nanoparticles (AgNPs), the intrinsic fluorescence of NS-CDs was quenched, showing the fluorescence state was off. Whereas the fluorescence of NS-CDs can be switched on when a trace amount of H2O2 was added. Based on this novel phenomenon, the peroxidase-like activity of NS-CDs-AgNPs by using 3,3′,5,5′-tetramethylbenzidine (TMB) chromogen and H2O2 as substrates was evaluated. The Km values of the prepared probe for H2O2 and TMB were 0.84 mM and 0.01 mM with the Vm of 6.65 × 10−8 M S−1 and 3.01 × 10−8 M S−1, respectively. The results showed that NS-CDs-AgNPs had good peroxidase-like activity and strong affinity to TMB and H2O2. It confirmed that there is a redox interaction between AgNPs and H2O2, and H2O2 can oxidize Ag to produce Ag+, which is the main reason that the fluorescence of NS-CDs-AgNPs can be activated by H2O2. The hydroxyl radical (·OH) was formed in the process of reaction, which can further oxidize TMB for color reaction. Meanwhile, glucose can be oxidized to produce H2O2 in the presence of glucose oxidase (GOx). Based on the phenomenon, a fluorimetric and colorimetric dual-mode sensor for glucose detection was established. Satisfactory results were obtained with the linear range of 0.1–80 μM for fluorimetric mode and 0.5–5 μM for colorimetric mode, respectively. Additionally, the LOD was below 0.32 μM and 0.21 μM, respectively. The method was successfully applied to determine the glucose in human serum with satisfactory recovery and RSD.

Structure and optical properties laser modification of the Ag-PbSe films.

The modification of the structure and optical properties of two-layer silver-lead selenide (Ag-PbSe) films because of exposure to laser nanosecond pulses of near-infrared radiation in the scanning mode is considered. The formation of micro-sized fragments and silver nanoparticles as a result of laser irradiation, as well as their effect on the spectral transmission and reflection of the film, has been revealed. It is shown that the presence of a silver layer on a PbSe film is an effective way to improve the optical characteristics of the material, which expands the scope of possible applications of chalcogenide films of this composition.

Discovery of Molecular Intermediates and Nonclassical Nanoparticle Formation Mechanisms by Liquid Phase Electron Microscopy and Reaction Throughput Analysis

Formation kinetics of metal nanoparticles are generally described via mass transport and thermodynamics‐based models, such as diffusion‐limited growth and classical nucleation theory (CNT). However, metal monomers are commonly assumed as precursors, leaving the identity of molecular intermediates and their contribution to nanoparticle formation unclear. Herein, liquid phase transmission electron microscopy (LPTEM) and reaction kinetic modeling are utilized to establish the nucleation and growth mechanisms and discover molecular intermediates during silver nanoparticle formation. Quantitative LPTEM measurements show that their nucleation rate decreases while growth rate is nearly invariant with electron dose rate. Reaction kinetic simulations show that Ag4 and Ag− follow a statistically similar dose rate dependence as the experimentally determined growth rate. We show that experimental growth rates are consistent with diffusion‐limited growth via the attachment of these species to nanoparticles. The dose rate dependence of nucleation rate is inconsistent with CNT. A reaction‐limited nucleation mechanism is proposed and it is demonstrated that experimental nucleation kinetics are consistent with Ag42+ aggregation rates at millisecond time scales. Reaction throughput analysis of the kinetic simulations uncovered formation and decay pathways mediating intermediate concentrations. We demonstrate the power of quantitative LPTEM combined with kinetic modeling for establishing nanoparticle formation mechanisms and principal intermediates.

Innovative valorization of spent liquors from hydrothermal carbonization for light-induced nanoparticle synthesis

To develop the biorefinery concept around the hydrothermal carbonization (HTC) process, it is essential to take advantage of the spent liquor (SL) produced. In general, SLs were reported to be treated by anaerobic digestion; however, some molecules present in SL are considered biological inhibitors. Nonetheless, this might be advantageous as these molecules exhibit antioxidant activity, opening a new valorization alternative as green reducing and capping agents for particle synthesis. Among the hydrothermally treated biomasses, the SL from Jatropha fruit husk (JFH) presented the highest antioxidant activity (TEAC ∼ 1597 µM g−1), increasing its capability to form metal nanoparticles due to their reducing effect. Still, nanoparticle aggregation was observed, evidencing its lack of capping effect. In this sense, the present study provides a novel approach to recovering the organic compounds from HTC spent liquor (OC-HTCSL) in viscous concentrates by evaporating the remaining water. Surprisingly, the JFH sample showed the lowest antioxidant activity and phenolic content after concentration. Nevertheless, this concentrate reflected a capping effect for the LED-assisted synthesis of silver nanoparticles. Stable silver colloids containing nanoparticles with an average diameter of 17 nm were successfully obtained. These silver nanoparticles retained their original morphology after being stored for six months. This research suggests that a lower antioxidant activity and phenolic content of the OC-HTCSL concentrate might be more effective in forming silver nanoparticles.

Green Synthesis of Silver Nanoparticles from Syzygium cumini (L.) Skeels Seed Extract and their Potential Medicinal Applications.

Nanotechnology is considered as one of the fastest-developing areas in the biomedicine field. Hence, the green synthesis of silver nanoparticles from Syzygium cumini seed extract was carried out in this study. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, FTIR (Fourier transform infrared), FE-SEM (Field Emission scanning electron microscopic), AFM (Atomic Force Microscope), XRD (X-ray diffraction), and EDX (Energy dispersive X-Ray). Their antioxidant and anti-inflammatory activity were evaluated by DPPH (2,2-diphenyl-1- picrylhydrazyl), PM (Phosphomolybdenum) assay, and albumin denaturation assay. Further, the antibacterial activity of the nanoparticles was studied against Gram-positive and Gram-negative bacteria using the agar well diffusion method. In addition, the antidiabetic activity of nanoparticles was studied by α-amylase and α-glucosidase inhibition assays. The surface plasmon resonance at 430 nm confirmed the formation of silver nanoparticles. They were stable and spherical in shape, with sizes ranging from 30 to 90 nm. The DPPH inhibition % of silver nanoparticles varied from 7.91±0.39% to 68.35±0.76%. The % inhibition of albumin denaturation was comparable to the diclofenac. Further, the results of antibacterial activity revealed that the zone of inhibition for all the test bacteria varied from 14.33±0.58 to 25.33±0.58 mm, where B. cereus was more susceptible. In addition, the % inhibition of α-amylase and α-glucosidase varied from 19.91±0.15% to 61.43±0.31% and 15.26±0.11% to 55.38±0.20%, respectively. This study is the first attempt of utilizing the silver nanoparticles synthesized from S. cumini seed extract for antidiabetic activity. The study suggests that these nanoparticles could be well utilized in pharmaceutical industries as an efficient antioxidant, anti-inflammatory, antibacterial, and antidiabetic drug.

Green synthesis of silver nanoparticles from the essential oil of Curcuma amada and their antihyperglycemic effect in STZ induced diabetic rats

A surfactant-free environmentally friendly approach for synthesising silver nanoparticles using Curcuma amada rhizome essential oil has been demonstrated. The composition and structure of silver nanoparticles are analysed using transmission electron microscopy, UV–visible spectroscopy, and Fourier transform infrared spectroscopy. The identification of a surface plasmon band at 428 nm by UV–visible spectroscopy provides preliminary evidence for the formation of silver nanoparticles. The transmission electron microscope verifies that the silver nanoparticles have an average particle size of 12.4 nm confirming a spherical shape. Self-stabilization of silver nanoparticles is discussed and correlated with the in-situ grafting of oil functional groups on surface nanoparticles. In-vitro and in-vivo antidiabetic studies are done for silver nanoparticles considering their antidiabetic potential, low toxicity, and the presence of curcumin functionalities on their surface. Specifically, the in-vitro study is done with α-amylase assay and in-vivo antidiabetic studies are done with streptozotocin-induceddiabetic rats. The percentage inhibition of α-amylase assay by silver nanoparticles is found concentration (20 μl–100 μl) dependent. The best result is seen at 100 μl concentration of silver nanoparticles (72 % inhibition) which is near to the standard taken (acarbose, 78 % inhibition). In-vivo study, the toxicity of two doses of Curcuma amada rhizome essential oil (200 mg/kg and 400 mg/kg) and synthesized silver nanoparticles (5 and 10 mg/kg) is checked and it is found safe. During the invivo study, silver nanoparticles with a dose of 5 mg/kg are capable of lowering the blood glucose level of all the streptozotocin-induced diabetic rats within 21 days (range ∼340–120 mg/dL). The histopathological analysis also supported the fact that there is an improvement in the pancreatic β-cells of all the diabetic groups compared to control group.

Stoichiometry crystallographic phase analysis and crystallinity integration of silver nanoparticles: A Rietveld refinement study

A highly crystalline phase of silver nanoparticles was successfully synthesized using silver nitrate as the precursor and trisodium citrate dihydrate as the chelating agent. Rietveld refinement analysis revealed that approximately 95.0 % of the synthesized material consisted of crystalline silver nanoparticles, with the remaining 5.0 % being unreacted starting material. XRD characterized the prominent crystalline phase, providing insights into lattice parameters were α = β = γ = 90.0°, a = b = c = 4.08871 Å; lattice strain 0.290 %, lattice volume 68.353 Å3 and average dislocation density 9.6 9× 10-4 nm−2. The most intense diffraction peak was attributed to the (111) plane at 2θ = 38.18°. The average crystallite size was determined to be 32.12 nm, confirming the formation of crystalline silver nanoparticles. The specific surface area of the synthesized silver nanoparticles was 18 m2/g Notably, the synthesized silver nanoparticles exhibited a higher degree of crystallinity (59.35 %) compared to the standard silver nitrate (38.46 %), indicating a highly crystalline nature. The crystallographic data confirmed the successful synthesis of highly crystalline silver nanoparticles with improved crystallinity over the reference material.