Size Of AgNPs Research Articles

Green synthesis of silver nanoparticles on polyamide fabrics using Scrophularia striata Boiss extract: Characterization, dyeing, and antibacterial properties

The green synthesis of silver nanoparticles (Ag NPs) on textiles using natural extracts is emerging as an innovative, eco-friendly approach for enhancing both antibacterial properties and dyeing performance. This study introduces a novel in-situ method for synthesizing Ag NPs directly on polyamide (PA) fabrics, utilizing Scrophularia striata Boiss extract (SBE) as a natural dye and reducing agent. UV–visible spectroscopy and dynamic light scattering (DLS) were used to characterize the synthesis process and determine the average particle size of Ag NPs. The data showed particle sizes of 62.5 nm and 56.1 nm when using flower and stem extracts, respectively. Surface morphology findings from scanning electron microscopy (SEM) and corresponding diffraction peaks in X-ray diffraction (XRD) confirmed the in situ formation of Ag NPs on the surface of PA fabric. Fabrics dyed with SBE and Ag NPs exhibited higher color strength (K/S values of 4.1 and 5.6 for flower and stem, respectively), showing 64 % and 100 % increases compared to samples without silver. Additionally, PA fabrics exhibited 100 % inhibition against E. coli and S. aureus bacteria. After 10 washing cycles, antibacterial activity was maintained at 88 % and 85 % for the stem extract and 83 % and 79 % for the flower extract. This research highlights the novel integration of natural dye and nanoparticle synthesis, providing a sustainable route for multifunctional textile development.

Environment-friendly Synthesis of AgNPs from Fimbristylis miliacea Flower Extract: Characterization and its Applications as an Antioxidant Activity, Anticancerous Activity and in the Reduction of 4-Nitrophenol

Background: Silver metal is useful in a variety of fields. Different silver salts exhibit good application in the organic transformation. The use of a green methodology in AgNPs preparation has gained interest of young researchers. Plant systems are employed in the green approach of preparing AgNPs, serving as both a stabilizing and reducing agent. Silver nanoparticles (AgNPs) made from silver salts exhibit a variety of biological activities and may be useful in organic transformation. Method: AgNPs were synthesized with the use of flower extract from Fimbristylis miliacea, which acts as a stabilizing and reducing agent. Result: Fimbristylis miliacea flower extract is used as a reducing and stabilising agent for preparation of AgNPs. These synthesised AgNPs were characterised by using FTIR, XRD, FESEM/ EDS, HR-TEM, TGA, and ICP-AES. Fimbristylis milliciea flower extract was subjected to FTIR and HR-LCMS analysis in order to identify the phytoconstituents that are responsible for the reduction of AgNO3. The HR-TEM shows particle size between 8.98434+0.69669nm and 19.07464+1.4384nm. The size of AgNPs determined by using HR-TEM shows good agreement with XRD particle size. The synthesized AgNPs show excellent antioxidant properties with IC50=56.45 μg/mL. The present study confers significant cytotoxic activity against MDA-MB-231 human breast cancer cell line culture (IC50= 61.97 μg/ml). The AgNPs show a faster reduction of 4-nitrophenol. Conclusion: In conclusion, we have prepared AgNPs by using Fimbristylis miliacea flower extract. The study further concludes that green synthesis of AgNPs has many advantages as compared to chemical methods, such as cost-effectiveness, rapid, and environment-friendly methods. The results indicated that the biosynthesized AgNPs have significant cytotoxic activity against the MDA-MB-231 breast cancer cell line. Further, it indicates that biosynthesized AgNPs can be a potential alternative agent for human breast cancer therapy. The cytotoxic potential can be used for treatments and provides a new method to develop molecules for cancer therapy. The catalytic activity of AgNPs was examined by using the reduction of 4-nitrophenol. It shows that the reduction of 4-nitrophenol in 6 minutes is confirmed by using 1H NMR analysis.

Perfluorodecanethiol-Functionalized Silver Nanoparticles on Polyester Films as High-Performance Surface-Enhanced Raman Spectroscopy Substrates.

The insufficient capabilities of current surface-enhanced Raman scattering (SERS) substrates in enriching dilute analytes from complex media severely restrict detection sensitivity, hampering practical applications. To meet this demand, in this study, a novel super hydrophobic membrane that can be directly prepared on a large scale based on the silver nanoparticles (AgNPs) functioning with perfluorodecanethiol (PFDT) is fabricated and evaluated as an SERS substrate. Firstly, polyester (PET) films modified with sodium chloride were proven to be capable of loading AgNPs, and the sizes of AgNPs were investigated. In addition, the PFDT concentration and reaction time for functionalizing the surface of AgNPs have been optimized. The relationship between the hydrophobic properties of the film and its SERS performance was then studied. The PET@Ag-PFDT film demonstrates two orders of magnitude superior SERS performance than the unmodified PET@Ag substrate, with a detection limit of folic acid approaching 5 × 10-10 M.

Green synthesis of Oscimum Sanctum mediated silver nanoparticles to fabricate sensors for hydrogen peroxide detection

In this study, silver nanoparticles (Ag NPs) of an average size of ∼15 nm have been produced using the green synthesis technique with Oscimum Sanctum leaf extract. Further, these nanoparticles have been used to prepare electrodes for electrochemical sensors to monitor hydrogen peroxide. Hydrogen peroxide sensors have many applications in different sectors, such as medical, agriculture, and industry. The optical and structural characteristics of the Ag NPs have been investigated by UV–visible absorption spectroscopy and XRD patterns. Particle size, shape, and morphology of as-synthesized Ag NPs have been analyzed using transmission and scanning electron microscopic techniques. These nanoparticles were deposited onto an indium-tin-oxide glass substrate using the electrophoretic technique, which was used as an electrode to assess the electro-oxidation of Ag NPs by cyclic voltammetry. The sensitivity of the sensor has been estimated to be 4.16 µA/mM-cm2. The limit of detection of the sensor is estimated to be 40 µM within the linear range of 5–28 mM. The lattice parameter, interplanar spacing, and crystallite size of Ag NPs have been quantified and estimated against pH variation.

Ecofriendly Filtration of Silver Nanoparticles for Ultrasensitive Surface-Enhanced (Resonance) Raman Spectroscopy-Based Detection.

In this study, a widely used colloid of Creighton AgNPs (ORI, 1-100 nm, mostly ≤ 40 nm, ∼10 μg mL-1) was rapidly manipulated via tangential flow filtration (TFF) for highly reproducible surface-enhanced (resonance) Raman spectroscopy (SE(R)RS) experiments down to the single-molecule (SM) level. The quasi-spherical AgNPs were size-selected, purified, and concentrated in two TFF fractions of a cutoff diameter of ∼40 nm: AgNP ≤ 40 (∼900 μg mL-1) and AgNP ≥ 40 (∼100 μg mL-1). The SE(R)S-based sensing capabilities of the two TFF fractions were then tested under pre-resonance (632.8 nm) and resonance (532.1 nm) excitation conditions for rhodamine 6G (R6G, 10-6-10-15 M). Both TFF isolates, AgNP ≤ 40 and AgNP ≥ 40, were more effective in adsorbing the R6G analyte (≥91%) than the original colloid (≥78%) at submonolayer coverages. Furthermore, the surface enhancement factors (SEF) of the two TFF fractions were markedly superior to those of ORI under all excitation conditions. SERS at 632.8 nm: only AgNP ≥ 40 enabled the detection of R6G at 10-9 M and produced the largest SEF (2.1 × 106). SE(R)RS and SM-SERRS at 532.1 nm: AgNP ≥ 40 gave rise to the largest SEF values (2.5 × 1010) corresponding to the SM regime down to 10-15 M of R6G. Nevertheless, AgNP ≤ 40 compensated for the size-dependence of the electromagnetic enhancements by an increase in the silver concentration, which led to SEF values comparable to those of AgNP ≥ 40 through additional resonance enhancements. TFF resulted into a ∼100-fold increase (AgNP ≤ 40) in the number of negatively charged AgNPs that were available to electrostatically bridge R6G cations and form SERRS "hot-spots" (AgNP-R6G-AgNP) within the focal volume. Evidently, the interplay between AgNP size, AgNP concentration, and excitation wavelength governs the SE(R)RS enhancements. This study demonstrated that TFF can facilitate the ecofriendly isolation of spherical AgNPs of controlled morphological and plasmonic properties for further enhancing their sensing capabilities as SE(R)RS substrates.

Alleviation of bovine serum albumin on the neurotoxicity of silver nanoparticles in zebrafish (Danio rerio) larvae

Silver nanoparticles (AgNPs) are ubiquitous in the aquatic environment and have attracted extensive attention to their toxic effects on aquatic species. However, responses of the nervous system to AgNPs are little known, especially co-existing with the ubiquitous natural organic matter (NOM), which is critical for the ability to act in aquatic species. Here, this study investigated the neurotoxicology of environmentally relevant AgNPs with or without bovine serum albumin (BSA; a classical NOM) to zebrafish (Danio rerio) using visualized transgenic zebrafish. Exposure to AgNPs reduced the locomotor behavior of zebrafish by 28%–45%, including swimming distance and velocity, exhibiting obvious behavioral inhibition. The visualized transgenic zebrafish treated with AgNPs showed developmental retardation in the early development of the heart, central nervous, and motor nerve, as well as the related neurodevelopment genes, which may be responsible for the lowered locomotor behavior. In addition, AgNPs can specifically interfere with the cholinergic system and affect neuronal signaling, ultimately leading to behavioral abnormalities. However, the co-existing BSA alleviated the neurotoxicity of AgNPs in zebrafish, which may partially be attributed to the increased size and electronegativity of AgNPs caused by BSA, thus reducing the direct interaction of AgNPs with cells. The interaction between BSA and the released Ag+ from AgNPs may also be responsible for the alleviation of the neurodevelopment dysfunction in zebrafish. These findings provide valuable insights into the toxicity and risks of AgNPs in natural aquatic environments.

Mitigating thermal burden and enhancing minor phase emission energy transfer in perovskite by introducing dopamine-mediated silver nanoparticles

Perovskite-based light-emitting diodes (PeLEDs) suffer from low wavelength and intensity instability during excited emission. This study incorporates dopamine-mediated silver nanoparticles (DA@AgNPs) into perovskite to enhance the performance of blue-light PeLEDs. Characterization studies highlight the crucial role of dopamine’s hydroxyl group in controlling the size and distribution of AgNPs. Due to the presence of amine group, dopamine acts as a “bridging linker,” facilitating precise integration of AgNPs with perovskite. DA@AgNPs–perovskite comprises a uniform cubic phase, indicating improved crystal quality and fewer defects than in pristine perovskite. DA@AgNPs prevent pinhole-defect-induced heat accumulation, reducing nonradiative energy and Joule heat. Additionally, DA@AgNPs enhance thermal conductivity and thus cooling efficiency. The energy transfer between minor and primary phase emissions is found to be highly efficient and to enhance primary phase emission through the surface plasmon resonance effect of DA@AgNPs. Finally, DA@AgNPs–perovskite is successfully employed in a high-performance blue-light PeLED (wavelength = 476 nm); the device’s external quantum efficiency is 11.2 %, luminance is 380.2 cd/m2, and emission stability is favorable (firmly maintained at 476–478 nm after strong excitation under 4.25 V for 1 h). This work provides insights into one means of improving blue-light PeLEDs, opening avenues for advancements in optoelectronics.

Exploring antibacterial effectiveness: A comparative analysis of green and chemical synthesis of silver nanoparticles against Staphylococcus aureus

BackgroundSilver nanoparticles (AgNPs) are renowned for their broad-spectrum antibacterial properties. Various synthesis methods, particularly green synthesis using biogenic agents, have garnered significant attention. However, the detailed impact of green-synthesized AgNPs on the antibacterial mechanism against Staphylococcus aureus remain unclear, limiting the full potential of green synthesis compared to chemical methods. MethodsAgNPs were synthesized via chemical (sodium citrate, NaBH4) and green synthesis (green tea leaves, cassia seed extract) methods. The synthesized AgNPs were evaluated for toxicity and antibacterial activity against Staphylococcus aureus. Significant findingsThis study revealed a strong correlation (R2>0.9) between minimal inhibitory concentration (MIC) and AgNP size for both synthesis methods, with a similar exponential trend. MIC values were 45, 40, 25, and 5 µg mL-1 for citrate-, NaBH4-, green tea extract-, and cassia seed extract-assisted synthesis, respectively. Green-synthesized AgNPs showed higher antibacterial activity than chemical AgNPs at comparable sizes. Chemical AgNPs exhibited low and fluctuating scavenging activity, while green methods were more consistent. Cytotoxicity was noted in chemical AgNPs and at high concentrations of green tea extract-assisted AgNPs. Bacterial membrane disruption and ROS accumulation were also observed, contributing to the enhanced antibacterial activity of green-synthesized AgNPs.

The Impact of Silver Nanoparticles’ Size on Biofilm Eradication

IntroductionEfficient intracanal disinfection is required for a successful regenerative endodontic treatment. Thus, this study aimed to identify the silver nanoparticles’ (NPs) size (AgNPs) with the highest antibiofilm efficacy when mixed with calcium hydroxide [Ca(OH)2] to eradicate an in vitro endodontic biofilm. MethodsThe various sizes of AgNPs and mixtures were characterized by scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible spectroscopy. A total of 168 dentin root segments were prepared, sterilized, and inoculated for 3 weeks with Actinomyces naeslundii and Fusobacterium nucleatum. Samples were randomly allocated to 4 experimental groups (n = 28/group): 2 nm AgNPs + 35% Ca(OH)2, 5 nm AgNPs + 35% Ca(OH)2, 10 nm AgNPs + 35% Ca(OH)2, and 35% Ca(OH)2 alone. Samples exposed to saline and triple antibiotic paste (TAP) acted as negative and positive control groups, respectively. After 1 and 2 weeks, samples were stained with LIVE/DEAD BacLight dye and examined under a confocal laser scanning microscope to determine the proportion of dead bacteria. ResultsThe characterization procedure revealed a spherical NP's structure with minor aggregations. Except for Ca(OH)2 group, all groups had significantly higher antibiofilm efficacy at 2 weeks. Both the 10 nm mixture (99.5%) and TAP (99.2%) exhibited the highest antibiofilm efficacy at 2 weeks and were not significantly different from one another (P > .05). No significant difference was noted between the 2 and 5 nm mixtures at 1 week (81% and 84%) and 2 weeks (89% and 91%). ConclusionThe 10 nm AgNPs (0.02%) + 35% Ca(OH)2 mixture exhibited the highest antibiofilm efficacy at 2 weeks compared to all other mixtures at both observation periods. Interestingly, the 10 nm mixture performed similarly to TAP at 2 weeks. Excluding Ca(OH)2 group, longer application significantly improved the antibiofilm efficacy of all tested medicaments. Clinical RelevanceThe 10 nm AgNPs + 35% Ca(OH)2 mixture revealed promising results as an intracanal medicament in the regenerative endodontic treatment protocol.

Influence of silver nanoparticles on enhancing performance of optical absorption property in a perovskite solar cell

This report presents a mostly numerical investigation of solar absorptance enhancement in PSCs through solving partial differential equations. The designed structural device comprised five layers of the transparent conducting contact (ITO), the electron transport layer (TiO2), the active layer (CH3NH3PBI3) embedding with plasmonic silver nanoparticles (AgNPs), the hole transporting layer (NiO), and the back reflectors (Ag). The calculation results showed that the device performance was highly dependent on the particle size of AgNP, structural formation and the location of the AgNPs. Overall, the optimum particle radius was r=10nm, located at the middle of the activated layer z=0nm, a 2-dimensional array of 2×2 particles per unit cell and an interparticle distance of 4nm were achieved for the AgNPs in the active layer (AL) of the PSCs with the highest optical enhancement of η=1.24.

Eco-friendly synthesis of silver nanoparticles from peel and juice C. limon and their antiviral efficacy against HSV-1 and SARS-CoV-2

The growing threat of viral infections requires innovative therapeutic approaches to safeguard human health. Nanomaterials emerge as a promising solution to overcome the limitations associated with conventional therapies. The eco-friendly synthesis of silver nanoparticles (AgNPs) currently represents a method that guarantees antimicrobial efficacy, safety, and cost-effectiveness. This study explores the use of AgNPs derived from the peel (Lp-AgNPs) and juice (Lj-AgNPs) Citrus limon “Ovale di Sorrento”, cultivars of the Campania region. The antiviral potential was tested against viruses belonging to the Coronaviridae and Herpesviridae. AgNPs were synthesized by reduction method using silver nitrate solution mixed with aqueous extract of C. limon peel and juice. The formation of Lp-AgNPs and Lj-AgNPs was assessed using a UV–Vis spectrophotometer. The size, ζ-potential, concentration, and morphology of AgNPs were evaluated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and field emission-scanning electron microscopy (FE-SEM). Cytotoxicity was evaluated in a concentration range between 500 and 7.8 µg/mL on VERO-76 and HaCaT cells, with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium test bromide (MTT). Antiviral activity consisted of virus pre-treatment, co-treatment, cellular pre-treatment, and post-infection tests versus HSV-1 and SARS-CoV-2 at a multiplicity of infections (MOI) of 0.01. Plaque reduction assays and real-time PCR provided data on the antiviral potential of tested compounds. Lp-AgNPs and Lj-AgNPs exhibited spherical morphology with respective diameters of 60 and 92 nm with concentrations of 4.22 and 4.84 × 1010 particles/mL, respectively. The MTT data demonstrated minimal cytotoxicity, with 50 % cytotoxic concentrations (CC50) of Lp-AgNPs and Lj-AgNPs against VERO cells of 754.6 and 486.7 µg/mL. Similarly, CC50 values against HaCaT were 457.3 µg/mL for Lp-AgNPs and 339.6 µg/mL for Lj-AgNPs, respectively. In the virus pre-treatment assay, 90 % inhibitory concentrations of HSV-1 and SARS-CoV-2 were 8.54–135.04 µg/mL for Lp-AgNPs and 6.13–186.77 µg/mL for Lj-AgNPs, respectively. The molecular investigation confirmed the antiviral data, recording a reduction in the UL54 and UL27 genes for HSV-1 and in the Spike (S) gene for SARS-CoV-2, following AgNP exposure. The results of this study suggest that Lp-AgNPs and Lj-AgNPs derived from C. Limon could offer a valid ecological, natural, local and safe strategy against viral infections.

Excellent antibacterial and anti-inflammatory efficacy of amoxicillin by AgNPs and their conjugates synthesized using Micromeria biflora crude flavonoid extracts

Antibacterial resistance is considered to be one of the major causes for mortality in coming years. In recent years green nanotechnology played a key role in addressing this problem. Biocompatible metal nanoparticles have gained popularity owing to their excellent therapeutic effects and minimal side effects. MethodWe report the synthesis of AgNPs and their amoxicillin conjugates (Ag-amoxi) using Micromeria biflora crude flavonoid extracts. The physicochemical properties of the synthesized NPs and Ag-amoxi conjugates were systematically evaluated using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR), and UV–visible (UV–Vis) spectroscopic techniques. ResultsThe average sizes of AgNPs and Ag-amoxi conjugates were 45 and 62 nm, respectively. We have also explored the antibacterial, antioxidant, anti-inflammatory, and analgesic properties of the AgNPs and Ag-amoxi conjugates through in vivo and in vitro analysis. The Ag-amoxi conjugates showed better antibacterial potential against Streptococcus Pneumoniae (S.P), Staphylococcus aureus (S.A), Pseudomonas aeruginosa (P.A), and Methicillin resistance Staphylococcus aureus (MRSA) strain both the drug and AgNPs. Similarly, in vivo anti-inflammatory studies revealed that both Ag-amoxi (68 %) and AgNPs (64 %) had strong anti-inflammatory effects, with (***p < 0.001) significance at a dose of 10 mg kg−1 body weight as compared to standard, amoxicillin (45 %), and flavonoids extract (48 %) at a dose of 100 mg kg−1. The findings of the antinociceptive activities (writhing and hot plate tests) demonstrated that the Ag-amoxi conjugates produced fewer writhing (15 in 20 s) and a shorter latency time of 22 s as compared to vehicle-treated (tramadol) animals, amoxicillin, and P.E at much lower doses. In vitro antioxidant studies revealed that the Ag-amoxi conjugate has the potential to be used as an antioxidant with an IC50 value of 43.58, compared with AgNPs (46.34), amoxicillin (58.17), compared to the standard of ascorbic acid (34.14). ConclusionThese results reveals that these biologically inspired AgNPs and Ag-amoxi conjugate could be used to improve antibiotic efficiency and could play a critical role in addressing the multidrug resistance problem in coming years.

Effect of biosynthesized silver nanoparticle size on antibacterial and anti-biofilm activity against pathogenic multi-drug resistant bacteria

Ag NPs have garnered significant attention in the field of biomedical applications due to their antibacterial, antifungal, antiviral, anti-inflammatory, and antiangiogenic effects. The present study aimed to establish a simple, reliable, cost-effective, and environmentally friendly approach for the synthesis of Ag NPs in different sizes using extracts from Syzygium aromaticum and Laurus nobilis and study the relationship between the size of Ag NPs and their antibacterial and anti-biofilm effectiveness. The synthesized Ag NPs were extensively characterized using various techniques, such as XRD, SEM, UV–vis and FTIR. Importantly, the study evaluated the antibacterial and anti-biofilm activities of Ag NPs in two different size (12 nm and 45 nm) against MDR and biofilm-producing pathogenic bacteria, including Kocuria rosea, Staphylococcus sciuri, and Staphylococcus lentus. The antibacterial activity of the larger Ag NPs-SA (45 nm) ranging between 14–25 mm while for the smaller Ag NPs-LN (12 nm) ranging between 26–48 mm against pathogenic bacteria. The MIC values for Ag NPs-LN were between 16 - 32 µg/ml while for Ag NPs-SA were 64 µg/ml. The MIC value of the Ag NPs decreased as their size decreased, indicating higher potency against the tested bacterial strains. Furthermore, the smaller Ag NPs-LN exhibited a higher rate of biofilm inhibition that reach 88% compared to the larger Ag NPs that reach 70%. This study provides novel evidence that the enhanced antibacterial and anti-biofilm activities of Ag NPs are directly correlated with their decreased nanoscale size. These findings highlight the potential of Ag NPs as a promising adjuvant in the management of bacterial infections, particularly those involving MDR and biofilm-producing pathogens, which pose a significant challenge in clinical settings.

Protective role of biosynthesized silver nanoparticles synthesized using sesame oil as biocontrol approach against Erwinia amylovora causing fire blight in pears (Pyrus communis L.)

Erwinia amylovora, the primary cause of fire blight, is thought to be one of the most difficult crop diseases to eradicate. The study aimed to evaluate the performance of essential sesame oil (SO) and silver nanoparticle synthesized by sesame oil SO-AgNPs against E. amylovora. Using GC-MS, it was found that essential sesame oil contains the main component of the oil was sesamin, asarninin, heptane, c-Sitosterol, anethol, and trimethyl -6- ((s) - 4-methylcyclohexan – 3 – en-1-yl)) tetrahydro -2H-pyran. The diluted sesame oil (SO) was used as a reducing agent in synthesis of AgNPs in aqueous solution. By using UV-Visible spectrophotometry (UV–Vis), Dynamic Light Scattering (DLS), High Resolution Transmission Electron Microscopy (HRTEM), and Fourier Transformer InfraRed (FTIR) analysis, the produced Ag NPs were studied. The average particle size of the spherical Ag NPs was determined to be 54.98 nm using data from HRTEM and DLS. SO-Ag NPs (20 µg/ml) showed a promising antibacterial against E. amylovora, producing a 22.9 mm Zone of Inhibition (ZOI) against E. amylovora, followed by SO-Ag NPs (10 ug/ml) that gave 18.2 mm ZOI., compared to gentamicin that produced 13.2 mm ZOI. The most effective inducers were SO-Ag NPs at 10 ug/ml, which decreased the percentage of disease severity by 27.5 and increased the percentage of protection against disease infection by 68.39%. SO-Ag NPs was the most effective inducers which decreased the contents of Malonaldehyde (MDA) and H2O2 by 41.3% and 77.1%. Applying SO-Ag NPs or SO lowered the level of malondialdehyde (MDA) and hydrogen peroxide (H2O2) and improved the fruit set and yield in infected trees. We could assume that, to prevent E. amylovora fire blight disease in pears, SO-Ag NPs, SO are safe, effective, and environmentally friendly alternatives to conventional antibiotics.

A time and temperature dependent biosynthesis of silver nanoparticles using the extract of Platycladus orientalis’ fruit

Silver nanoparticles (AgNPs) have gained notable/ huge attention, particularly in the biomedical and antibacterial fields, owing to their distinctive characteristics. Biological synthesis of AgNPs is a prominent method due to its ease of preparation, eco-friendliness, non-toxicity and time efficiency. Herein, AgNPs were synthesized using an extract from "Platycladus orientalis" and their antimicrobial and biological properties were thoroughly investigated. The scaling down of Ag⁺ to Ag⁰ was evident through the appearance of a yellow brownish colour. AgNPs were characterized by UV–Visible spectrum, X-ray diffraction (XRD), and scanning electron microscopy (SEM). UV–Visible spectroscopy revealed absorption peaks at around 440 nm for AgNPs synthesized from fruits’ seat coat of Platycladus orientalis. TEM analysis indicates the average size of AgNPs is approximately 50 nm. Powder XRD confirmed the crystalline nature of the AgNPs, with prominent peaks corresponding to face-centred cubic structures. FTIR analysis identified key functional groups involved in the synthesis process. SEM images displayed agglomerated AgNPs with varying diameters and particle dispersion. Molecular docking results showed favourable binding interactions of AgNPs with the protein 2BTD, with a docking score of -3342 kcal/mol, indicating potential biological activity. These findings highlight the effective synthesis of AgNPs using Platycladus orientalis and their significant potential for biomedical applications.

Phytofabrication of Silver Nanoparticles Using Pomegranate Juice Extract for Antioxidant, Antimicrobial and Cytotoxic Activities

AbstractIn the current research, monowave‐assisted biosynthesis of AgNPs utilising aqueous Pomegranate Juice extract (PJE) for antioxidant, antimicrobial and cytotoxic activities were evaluated. The synthetic approach used for the biosynthesis of AgNPs was simple, affordable and eco‐friendly. UV‐Visible, DLS, FTIR, XRD, FE‐SEM and HR‐TEM techniques were used to characterize the synthesized AgNPs. The DLS technique confirmed the monodispersed nature and zeta potential of −25.8 mV. FTIR technique revealed that OH functional groups of phytochemicals were crucial for the reduction and stabilization of AgNPs. FESEM and HRTEM techniques confirmed that biosynthesized AgNPs appeared spherical and triangular. XRD analysis resulted in 18.04 nm size of AgNPs. The antioxidant capacityof biosynthesized AgNPs was analysed via DPPH (IC50 35.20 μg/mL), ABTS (IC50 37.77 μg/mL), FRAP (4.37 mM Fe(II)/mL at 90 μg/mL) and total antioxidant (77.16 g AAE/mL at 90 μg/mL) assays. Biosynthesized AgNPs exhibited antifungal activity against Colletotrichum gloesporioides, Colletotrichum graminicola and antibacterial activity against Xanthomonas axonopodis, Klebsiella aerogenes at 50 μg/mL. Owing to these studies, synthesized AgNPs may be valuable in the future for biomedical and agricultural applications.

Stimuli-responsive synthesis of silver nanoparticles applying green and chemical reduction approaches

Introduction: The current study reports the comparative stimuli-responsive synthesis of silver nanoparticles (AgNPs) with various sizes and morphologies employing Lycium ruthenicum extract and sodium citrate solutions. Methods: The morphology and size of AgNPs were regulated by varying the pH values, concentrations of the extract solution, and temperatures in the reaction medium. The prepared AgNPs were assessed via various instrumental analyses, including UV-Vis, FTIR, XRD, TEM, and DLS. Results: The L. ruthenicum extract displayed several functional groups that reduced the Ag ions to the AgNPs at different values of pH. However, the primary chemical structure of L. ruthenicum was virtually unaltered at these conditions. Variations in the pH and extract concentration of the reaction medium yielded AgNPs of different sizes and morphologies. Both bio- and chemo-synthesized AgNPs revealed a relatively dispersed sphere-shaped morphology under alkaline conditions (≈ 36 nm). Conclusion: This study introduced a simple, valuable, and green technique for stimuli-sensitive AgNPs synthesis employing the L. ruthenicum extract.

Effect of NiAl alloy microparticles deposited in flexible SERS substrates on the limit of detection of rhodamine B molecules.

Flexible-SERS (FSERS) substrates were fabricated by depositing Ni64Al36(NiAl)-alloy-microparticles and/or spherical Ag-NPs (sizes of 10-40 nm) on recycled plastics, which had an aluminum layer on their surface. First, FSERS substrates made of Al + Ag-NPs and an area of 1 cm2 were used to detect rhodamine B (RhB) molecules. The limit-of-detection (LOD) for RhB was 8.35 × 10-22 moles (∼503 molecules), and the enhancement factor (EF) was 3.11 × 1015. After adding NiAl-microparticles to the substrate, the LOD decreased to 8.35 × 10-24 moles (∼5 molecules) and the EF was increased to 2.05 × 1017. Such EF values were calculated with respect to substrates made only with Al + NiAl-alloy (without Ag-NPs), which did not show any Raman signal. Other FSERS substrates were made with graphene-layer + Ag-NPs or graphene-layer + NiAl-alloy + Ag-Nps, and the best LOD and EF values were 8.35 × 10-22 moles and 6.89 × 1015, respectively. Overall, combining the Ag-NPs and NiAl-alloy microparticles allowed for the zeptomole detection of RhB. This was possible due to the formation of Ag aggregates around the alloy microparticles, which enhanced the number of hotspots. If no alloy is present in the FSERS substrates, the detection of RhB is lowered. Overall, we presented a low-cost FSERS substrate that does not require expensive Au films or Au-NPs (as previously reported) to detect RhB at the zeptomole level.

Comparative Study on Silver Nanoparticle Synthesis Using Male and Female Pistacia Khinjuk Leaf Extracts: Enhanced Efficacy of Female Leaf Extracts

AbstractThis study aims to uncover the potential differences in bioactive compounds present in leaf extracts obtained from female and male individuals of Pistacia khinjuk, abundantly found in the Southeast Anatolia region of Turkey, and their roles in influencing the properties of synthesized silver nanoparticles (AgNPs). Results obtained through TEM and SEM imaging techniques determined the morphology and size of AgNPs synthesized from female (FL‐AgNPs) and male (ML‐AgNPs) leaf extracts. Additionally, FTIR spectrum analysis demonstrated the chemical composition of the FL‐AgNPs, ML‐AgNPs, and the extracts. Zeta potential and zeta sizer analyses revealed differences between nanoparticles obtained from female and male plants. The total phenolic content of leaf extracts from female plants is significantly higher than that obtained from male plants (female plants: 30.68±0.26 mg GAE/g, male plants: 24.22±0.37 mg GAE/g). Furthermore, FL‐AgNPs (43.2±2.64 mg GAE/g) exhibit higher antioxidant activity compared to ML‐AgNPs (31.7±1.16 mg GAE/g). ICP‐MS analyses indicate that FL‐AgNPs are synthesized with higher efficiency compared to ML‐AgNPs (FL‐AgNPs: 99.90±0.106 %, ML‐AgNPs: 94.99±0.079 %). Finally, the antibacterial efficacy of FL‐AgNPs and ML‐AgNPs nanoparticles was evaluated agar well diffusion method against the pathogen Escherichia coli (E.Coli) and Staphylococcus aureus (S. Aureus]

Green synthesis and antibacterial-antibiofilm properties of biogenic silver nanoparticles

The biosynthesis of metallic nanoparticles is gaining prominence as an alternative to traditional physicochemical methods, offering several advantages such as simplicity, non-toxicity, lower energy requirements and short reaction times leading to environmentally sustainable processes. The aims of this work were: to study the extracellular biosynthesis of silver nanoparticles (AgNPs) by Pseudomonas extremaustralis 2E-UNGS, to characterise the shape, monodispersity and size of AgNPs, to explore their antimicrobial and antibiofilm activities, and to evaluate the role of nitrate reductase activity in the biosynthesis process. The novelty of this work relies on the development of a green and sustainable method for the synthesis of stable AgNPs with optimal properties for potential applications in antimicrobial materials, especially when incorporated into polymeric matrices or used as agrochemical substitutes. Optimal conditions for the biosynthesis of spherical AgNPs were determined to be pH 7, 38 °C, 4 h of darkness and 120 rpm using stationary phase culture supernatants of P. extremaustralis 2E-UNGS. The involvement of extracellular nitrate reductase in AgNP biosynthesis was confirmed by enzymatic assays and supported by bioinformatics analysis, which identified the presence of the napA2 gene linked to the nirBD cluster. Antimicrobial assays demonstrated the inhibitory effect of AgNPs against both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa PA01 in both planktonic and biofilm states. In addition, the potential application of AgNPs in innovative antibacterial polymers was explored by incorporating them into polyurethane matrices either alone (PU-AgNP) or in combination with crystal violet as a photosensitizer (PU-AgNP-CV). Subsequent inoculation with a clinical isolate of Pseudomonas aeruginosa resulted in significant reductions in viable bacterial counts on both PU-AgNP-CV and PU-AgNP. Biogenic AgNPs showed antibacterial and antibiofilm properties for new antimicrobial material development.