Reduction Of Silver Salt Research Articles

One-Pot Synthesis of Functionalised rGO/AgNPs Hybrids as Pigments for Highly Conductive Printing Inks.

This work provides a method for the development of conductive water-based printing inks for gravure, flexography and screen-printing incorporating commercial resins that are already used in the printing industry. The development of the respective conductive materials/pigments is based on the simultaneous (in one step) reduction of silver salts and graphene oxide in the presence of 2,5-diaminobenzenesulfonic acid that is used for the first time as the common in-situ reducing agent for these two reactions. The presence of aminophenylsulfonic derivatives is essential for the reduction procedure and in parallel leads to the enrichment of the graphene surface with aminophenylsulfonic groups that provide a high hydrophilicity to the final materials/pigments.

Investigation of In Vitro Anticancer and Apoptotic Potential of Biofabricated Silver Nanoparticles from Cardamine hirsuta (L.) Leaf Extract against Caco-2 Cell Line

Green nanoparticle (NPs) synthesis is eco-friendly, non-toxic, and the NPs have demonstrated improved biocompatibility for use in healthcare. This study evaluated the biogenic synthesis of AgNPs from the leaves of Cardamine hirsuta L. and their biological properties. The UV-Vis. spectra at 411 nm exhibited a distinct resonance spectrum for C-AgNPs produced from C. hirsuta L. FT-IR analysis exhibited the presence of functional groups of phyto-compounds of C. hirsuta responsible of silver salt reduction and capping agents of C-AgNPs. The microscopic-based study, such as HR-TEM analysis, showed that the particles were uniformly distributed, spherical, and ranged in size from 5.36 to 87.65 nm. EDX analysis confirmed a silver (Ag) content of 36.3% by weight, and XRD analysis exhibited the face-centred cubic (FCC) crystalline nature of C-AgNPs. DLS measured the mean particle size of 76.5 nm. The zeta potential was significant at −27.9 mV, and TGA analysis revealed that C-AgNPs had higher thermal stability. C-AgNPs demonstrated moderate antimicrobial activity against the tested pathogens. In addition, the anti-proliferative activity measured by the MTT assay on the Caco-2 cell line demonstrated decreased cell viability with increasing C-AgNPs dosage, with an IC50 concentration of 49.14 µg/mL. In addition, an Annexin-V/Propidium iodide flow cytometric study was utilized to evaluate the induction of apoptosis in cancer cells. Early and late apoptosis cell populations increased significantly compared to the untreated control. Therefore, green-synthesized C-AgNPs have significant antimicrobial and anti-proliferative abilities, making them intriguing options for future biomedical applications.

Facile and Green Synthesis of Novel Fluorescent Carbon Quantum Dots and Their Silver Heterostructure: An In Vitro Anticancer Activity and Imaging on Colorectal Carcinoma.

Carbon dots (CQDs) have been widely investigated as prime candidates for developing a tumor theranostic platform due to their tunable fluorescence emission and excitation, high water solubility, good photostability, and biocompatibility. Among the CQDs, natural CQDs are an emerging class of nanomaterials in the carbon family. Herein, highly fluorescent carbon quantum dots (CQDs) were synthesized from orange juice using a one-step hydrothermal method and characterized by different techniques. After that, CQD/Ag heterostructures were synthesized by the reduction of silver salt, in particular silver nitrate (AgNO3) solution using sodium borohydride (NaBH4) in different ratios. The photostability and characterization of CQD/Ag heterostructures were investigated. At last, a comparative cellular toxicity measurement was done to select the superior CQD/Ag heterostructure in the human colorectal carcinoma (HCT 116) cell line along with the imaging property. The detailed cell death signaling was also observed in the HCT 116 cell line via the ROS-dependent mitochondrial-mediated pathway, where Akt (RAC-α serine/threonine-protein kinase) played a important role.

Green-Based Approach to Synthesize Silver Nanoparticles Using the Fungal Endophyte Penicillium oxalicum and Their Antimicrobial, Antioxidant, and In Vitro Anticancer Potential.

A green-based approach for the synthesis of silver nanoparticles has gained tremendous attention in biomedical applications. Fungal endophytes have been recognized as a remarkable biological source for the synthesis of potential nanodrugs. The present study focuses on the fabrication of silver nanoparticles using the fungal endophyte Penicillium oxalicum (POAgNPs) associated with the leaf of the Amoora rohituka plant. Sharp UV-visible spectra at 420 nm appeared due to the surface plasmon resonance of POAgNPs and the reduction of silver salt. FT-IR analysis revealed the presence of functional groups of bioactive compounds of P. oxalicum responsible for the reduction of silver salt and validated the synthesis of POAgNPs. A high degree of crystallinity was revealed through XRD analysis, and microscopy-based characterizations such as AFM, TEM, and FESEM showed uniformly distributed, and spherically shaped nanoparticles. Furthermore, POAgNPs showed a potential inhibitory effect against bacterial and fungal strains of pathogenic nature. POAgNPs also exhibited potential antioxidant activity against the synthetically generated free radicals such as DPPH, superoxide, hydroxyl, and nitric oxide with EC50 values of 9.034 ± 0.449, 56.378 ± 1.137, 34.094 ± 1.944, and 61.219 ± 0.69 μg/mL, respectively. Moreover, POAgNPs exhibited cytotoxic potential against the breast cancer cell lines, MDA-MB-231 and MCF-7 with IC50 values of 20.080 ± 0.761 and 40.038 ± 1.022 μg/mL, respectively. POAgNPs showed anticancer potential through inhibition of wound closure and by altering the nuclear morphology of MDA-MB-231 and MCF-7 cells. Further anticancer activity revealed that POAgNPs induced apoptosis in MDA-MB-231 and MCF-7 cells by differential expression of genes related to apoptosis, tumor suppression, and cell cycle arrest and increased the level of Caspase-3. The novel study showed that P. oxalicum-mediated silver nanoparticles exhibit potential biological activity, which can be exploited as nanodrugs in clinical applications.

Synthesis of biocompatible Konjac glucomannan stabilized silver nanoparticles, with Asystasia gangetica phenolic extract for colorimetric detection of mercury (II) ion

Herein, the synthesis of a biocompatible silver nanoparticles (AgNPs), for colorimetric detection of toxic mercury (II) ion (Hg2+), is reported. Phenolic-rich fraction of Asystasia gangetica leaf was extracted and used as a reductant of silver salt, all within the hydrophilic konjac glucomannan (KgM) solution as stabilizer, at room temperature (RT). The bioactive components of Asystasia gangetica phenolic extract (AGPE), as elucidated with a (UHPLC-MS-QTOF-MS), revealed plethora of phenolic compounds, which can facilitate the reduction of silver salt at ambient conditions. Sparkling yellow colloidal solution of KgM-AgNPs was realized within 1 h, at RT, having a UV–vis maximum at 420 nm. KgM-AgNPs was characterized using UV–vis, Raman and (FTIR), TEM, SEM, EDS, XRD, TGA/DTG. TEM and FESEM images showed that KgM-AgNPs were spherical, with particle size distribution around 10–15 nm from TEM. The KgM-AgNPs biocompatibility was investigated on mouse L929 fibrobroblast and rat erythrocytes, without any harmful damages on the tested cells. In aqueous environment, KgM-AgNPs demonstrated good detection capacity toward Hg2+, in a Hg2+ concentration dependent fashion, within 3 min. Absorbance ratios (A360/A408) was linear with Hg2+ concentrations from 0.010–10.0 to 10.0–60.0 µM, with an estimated (LOD) of 3.25 nM. The probe was applied in lake water sample, with satisfactory accuracy.

Highly sensitive and selective thiourea electrochemical sensor based on novel silver nanoparticles/chitosan nanocomposite

Herein, we have proposed a thiourea sensor using a novel silver decorated chitosan (Ag@CTSN) nanocomposite modified glassy carbon electrode (GCE). The catalyst was fabricated using a simple photo-reduction technique. In where, chitosan surface was decorated with silver nanoparticles via the photochemical reduction of silver salt to obtain Ag@CTSN nanocomposite. The morphology and structural properties of fabricated electrocatalyst was successfully characterized using advanced analytical techniques and reviled that silver nanoparticles was nicely dispersed over the host matrix; chitosan. Morphological study shown the non-aggregated form of silver nanoparticles with an average diameter of 20.85 nm. In the electrochemical investigations, the Ag@CTSN/GCE sensor showed good sensitivity of 15.88 µAmM−1 cm−2, a wide detection range (200–3600 µM), and a low limit of detection (LOD ~18 μM). The newly developed thiourea sensor was further used to check the potential chemical interference using several common chemicals, presenting an extreme selectivity in thiourea detection. The Ag@CTSN/GCE sensor also exhibited ⁓100% recovery results from spiked real samples. Excellent reproducibility, repeatability, and operational and storage stability was observed in the newly fabricated sensor.

Optical microstructures based on surface-selective growth of Ag nanoparticles on thermally poled soda-lime glass

Glass is important as a substrate for coatings in a wide range of applications or as a substrate for the fabrication of optical micro/nano structures. Coating by wet chemistry methods often demands modifications of the glass surface properties involving several steps. In addition, the micro/nano structuring is usually a several-step process. New methods that are simpler and more efficient are being proposed. One of them is glass poling that has been used to obtain surface relief on glass and, together with electric field assisted dissolution, for metal nanostructures in glass/metal systems. In this work, we demonstrate that poling increases the susceptibility of the glass surface for coating with Ag nanoparticles synthesized in situ by silver salt reduction. It is shown that a selectively poled glass surface can be used as a template to obtain optical microstructures consisting of Ag nanoparticles in only three simple steps. As a proof-of-concept, the method is used to fabricate diffraction gratings with an optical response that can be tuned by adjusting the Ag concentration. This approach is more versatile than the standard structuring by electric field assisted dissolution, as it does not require application of an elevated temperature once the coating is formed, which might change or destroy the properties of the thermally sensitive coating species or morphologies.

Биоцидные нанокомпозиционные материалы на основе оксида цинка

The aim of this work is the synthesis of composite materials based on highly dispersed zinc oxide and the study of the effect of synthesis conditions on their composition and structure. Finely dispersed zinc oxide was prepared by a thermal decomposition of products of ZnCl2 and (NH4)2CO3 interaction. ZnO nanocomposite materials modified by silver were synthesized by chemical and photochemical reduction of silver salts in a zinc oxide matrix. It is shown that, in the case of chemical reduction, Ag/ZnO nanocomposites with an average silver particle size of 22 nm are obtained. When using the photochemical method of reduction of silver ions, the effect of the ratio of components on the morphology of the samples was noted: at a ratio of ZnO:AgNO3:NaCl - 1:0.5:0.5, the formation of Ag/AgCl/ZnO nanocomposites is observed, with an increase in the silver salt content, the formation of silver nanoparticles is not observed, and AgCl/ZnO nanocomposites are formed. The high bactericidal activity of Ag/ZnО was shown.

Seaweed polysaccharide mediated synthesis of silver nanoparticles and its enhanced disease resistance in Oreochromis mossambicus

ObjectivePreliminary aim of this research work focuses on testing the efficacy of silver nanoparticles synthesised using water soluble polysaccharides extracted from seaweeds against pathogenic fish bacteria. The emergence of various virulence pathogens during the culturing period leads to mass mortality and influence the loss of aquaculture production. MethodsThe intervention of nanotechnology in the field of aquaculture improves the growth and immunity of aquatic animals when the part of nanomaterials mixed with fish feed. Sometimes the green synthesis of silver nanoparticles prepared from the seaweed polysaccharide play a vital role in the disease controlling strategies in aquaculture farming. The nanoparticle formation and confirmation was charecterized by Ultra Visible Spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Dynamic Light Scattering (DLS). Results and ConclusionBiologically synthesized silver nanoparticles have been used as an alternative method for commercial antibiotics to control such pathogenic infection with 70–80% of survival rate. Polysaccharides of Caulerpa racemosa was used as a reducing agent in this present study. Particularly the phytochemicals are involved in the silver salt reduction process. Total polyphenol, total flavonoids, total antioxidant, hydroxyl radical scavenging assay and DPPH was found to be 12.32 mg/g, 18.44 mg/g, 38.12 mg/g equivalence, 82.2% and 49.05% respectively. Biologically synthesised AgNps capable of preventing the Pseudomonas aeruginosa infection in tilapia, it was proved by in vitro and in vivo antibacterial activities. Present study provided the ample achievement and these findings found to be effective in controlling the Pseudomonas infection in tilapia fishes.

Efficient and green synthesis of silver nanocomposite using guar gum for voltammetric determination of diphenylamine

In this study, silver nanoparticle embedded on guar gum (AgNP/GG) nanocomposite was synthesized thoroughly in greenway via a simple in situ method by silver salt reduction using the guar gum (GG) polymer matrix. The highly water-soluble polysaccharide material (GG) was served as both stabilizing and reducing agent. Its structure and morphology were characterized by XRD, FT-IR, TEM, and UV−Vis spectroscopy. EIS, CV, and DPV methods have also been employed to investigate the electrochemical performance of the AgNP/GG nanocomposite. Analytical parameters such as loading amount of catalyst, scan rate, pH value, cyclic stability, repeatability, and reproducibility were optimized. The AgNP/GG/SPCE shows a distinct electrocatalytic oxidation of diphenylamine (DPA) in a wide linear range (WLR) of 0.01−9.09 µM, a higher sensitivity of 6.879 µM cm−2, and a limit of detection (LoD) of 5.4 nM (S/N = 3). The fabricated electrode exhibits an outstanding electrocatalytic performance in terms of good reproducibility, high stability, and acceptable anti-interference ability. In addition, this work advances the feasibility to determine DPA in apple juice sample with satisfactory recovery results.

Highly efficient transfer hydrogenation of 4-Methoxybenzaldehyde over supported silver nanoparticles

Silver nanoparticles were simply synthesized via the reduction of silver salt using ascorbic acid as reducing agents. These silver nanoparticles were then embedded on the supports X (X = Bent, C, ZnO, Zeolit, and Al2O3) in high yield. The optical property of these catalysts was characterized by UV-Vis spectroscopy, the structure of Ag-X was studied by Powder X Ray Diffraction (PXRD), the distribution of Ag particles in X was studied by Transmission Electron Microscopy (TEM), the specific surface area of catalysts was evaluated by N2 adsorption isotherms analysis at 77K. All results consisted to the loading method, indeed, TEM image indicated that the silver nanoparticles size is in range of 10¸15 nm and fully loaded into X. The efficiency of these catalysts was performed on the transfer hydrogenation of 4-methoxybenzaldehyde in the presence of potassium hydroxide as base at atmosphere pressure. The results showed that Ag-X exhibited high activities of up to 89.8% conversion within 60 min at 60 °C in the case of Ag-C catalyst.

An environment friendly free-standing cellulose membrane derived for catalytic reduction of 4-nitrophenol: A sustainable approach

Catalytic active and high flux free standing cellulose membrane is developed through mussel inspired polydopamine (PDA) chemistry using facile vacuum filtration method. Herein, quasi-spherical silver nanoparticles (AgNPs) illuminated nanocelluose (NC) fiber (AgNPs@NC) based membrane was fabricated by in-situ reduction of silver salt over the surface of nanometer thick PDA coated synthesized NC. The permeation behavior of the membranes was studied using pure water under gravimetric condition. The catalytic activity was evaluated by assessing the reduction of 4-nitrophenol (4-NP) as a water contaminant. The conversion efficiency of the 4-NP by the stacking membranes under gravimetric condition showed above 95 %. The catalytic activity was also studied toward reduction of 4-NP in a batch reactor and complete conversion could be accomplished within 8 min having turn over frequency (TOF) 2.25 × 10−3 molecules per gram per min. High water flux of the fabricated membrane was possibly due to the hydrophilicity of the PDA coated NC and hydrophobic pushing of AgNPs. Excellent catalytic activity of the synthesized AgNPs@NC membrane can be described by the synergistic effect of PDA coated NC and AgNPs. Beside this, higher number of catalytic reusability proved excellent bonding ability of adhesive like PDA between NC and AgNPs. In future, the fabricated AgNPs@NC membrane would be a potential candidate as catalytic converter for industrial applications.

Synthesis of Citrate-Stabilized Silver Nanoparticles Modified by Thermal and pH Preconditioned Tannic Acid.

Silver nanoparticles (AgNPs) may be synthesized by many different methods, with those based on the thermal reduction of silver salts by citric acid or citric acid/tannic acid being amongst the most commonly used. These methods, although widely used and technically simple, can produce particles in which the size, polydispersivity and morphology can vary greatly. In this work nearly mono-dispersed spherical AgNPs have been synthesized via a one-step reduction method by using sodium citrate and varying quantities of Tannic Acid (TA), which was thermally conditioned prior to use in the growth process. It was found that the final size can be further tailored by controlling the amount of TA and the thermal conditioning of the TA at 60 °C at different time points, which changes the size and polydispersivity of AgNPs. To better understand the origin of this effect, optical spectroscopic analysis and 1H NMR of the TA following mild thermal conditioning of the solution have been done. Comparison of thermally conditioned TA and TA exposed to basic pH shows that similar chemical modifications occur and consequently produce similar effects on growth when used in the synthesis of AgNPs. It is proposed that thermal preconditioning of the TA introduces either chemical or structural changes, which decrease the final particle size under a given total silver content.

<p>Species-Specific in vitro and in vivo Evaluation of Toxicity of Silver Nanoparticles Stabilized with Gum Arabic Protein</p>

IntroductionWe report, herein, in vitro, and in vivo toxicity evaluation of silver nanoparticles stabilized with gum arabic protein (AgNP-GP) in Daphnia similis, Danio rerio embryos and in Sprague Dawley rats.PurposeThe objective of this investigation was to evaluate in vitro and in vivo toxicity of silver nanoparticles stabilized with gum arabic protein (AgNP-GP), in multispecies due to the recognition that toxicity evaluations beyond a single species reflect the environmental realism. In the present study, AgNP-GP was synthesized through the reduction of silver salt using the tri-alanine-phosphine peptide (commonly referred to as “Katti Peptide”) and stabilized using gum arabic protein.MethodsIn vitro cytotoxicity tests were performed according to ISO 10993–5 protocols to assess cytotoxicity index (IC50) values. Acute ecotoxicity (EC50) studies were performed using Daphnia similis, according to the ABNT NBR 15088 protocols. In vivo toxicity also included evaluation of acute embryotoxicity using Danio rerio (zebrafish) embryos following the OECD No. 236 guidelines. We also used Sprague Dawley rats to assess the toxicity of AgNP-GP in doses from 2.5 to 10.0 mg kg−1 body weight.ResultsAgNP-GP nanoparticles were characterized through UV (405 nm), core size (20±5 nm through TEM), hydrodynamic size (70–80 nm), Zeta (ζ) potential (- 26 mV) using DLS and Powder X ray diffraction (PXRD) and EDS. PXRD showed pattern consistent with the Ag (1 1 1) peak. EC50 in Daphnia similis was 4.40 (3.59–5.40) μg L−1. In the zebrafish species, LC50 was 177 μg L−1. Oral administration of AgNP-GP in Sprague Dawley rats for a period of 28 days revealed no adverse effects in doses of up to 10.0 mg kg−1 b.w. in both male and female animals.ConclusionThe non-toxicity of AgNP-GP in rats offers a myriad of applications of AgNP-GP in health and hygiene for use as antibiotics, antimicrobial and antifungal agents.

Ecofriendly Catechol Lipid Bioresin for Low-Temperature Processed Electrode Patterns with Strong Durability.

We demonstrated catechol lipid-based bioresin, which is collected from lacquer trees, to produce conductive pastes that can be processed at low temperatures, which are highly adhesive and multidurable. Our conductive paste, which consists of catechol lipid-based urushiol resin and a multimodal mixture of silver fillers, exhibited stable dispersion with shear thinning properties. The urushiol lacquer induced spontaneous reduction of silver salt at the surface of the silver fillers, thereby contributing to lower the contact resistance between conductive fillers in the electrical conduction. Furthermore, the directional volume shrinkage of the urushiol lacquer matrix in a cross-linking reaction resulted in a highly ordered microstructure of the silver fillers with layer-by-layer stacking of the silver flakes. This structure contributed to the improvement of the electrical contact between fillers as well as excellent mechanical hardness, anti-scratch capability, and the long-term environmental stability of the conductive films. Conductive films based on the silver paste with urushiol lacquer exhibited low electrical resistivity below 4.4 × 10-5 Ω cm, 5B-class strong adhesion strength, and high hardness exceeding 200 MPa. Finally, we demonstrated the facile room-temperature processability and screen printability of the UL-Ag paste by fabricating a printed antenna and three-dimensional (3D) electrode assembly based on a plastic 3D block.

Synthesis of graphite/Ag/AgCl nanocomposite electrode materials

Nanocomposite electrode materials composed of graphite, Ag and AgCl were prepared by impregnation of graphite with a suspension of silver nanoparticles followed by anodizing in hydrochloric acid to obtain a layer of silver chloride on the surface of the nanoparticles. Silver nanoparticles were synthesized by the reduction of silver salts in benzyl alcohol. It was shown that the mass fraction of 1% Ag in the nanocomposite is optimal for creating a uniform coating of carbon surface with nanoparticles. The preliminary treatment of the graphite surface by the 0.75HNO3-0.25H2SO4 mixture resulted in formation of silver nanoparticles with the smallest size of 5–10 nm and their uniform distribution over the graphite surface. It was found that the nanocomposite electrode materials under study meet general requirements for electrocardiographic electrodes.

Gold@Silver@Gold Core Double-Shell Nanoparticles: Synthesis and Aggregation-Enhanced Two-Photon Photoluminescence Evaluation

A facile, straightforward, and low-cost method is proposed to synthesize gold@silver@gold core double-shell nanoparticles. The technique is a seed-mediated growth protocol that contains four steps of (1) gold seed synthesis, (2) gold seed growth, (3) silver layer coating through silver salt reduction, and (4) gold layer deposition via gold precursor reduction. The prepared nanoparticles had a narrow size distribution and the average particle size of 28 ± 1 nm. Cysteine was introduced to the nanoparticles solution as a coupling agent to assemble nanoparticles. Aggregation-induced two-photon photoluminescence enhancement of three types assembled nanoparticles, i.e., gold@silver@gold, gold@silver, and gold nanoparticles, was studied. It was observed that the assembled core double-shell nanoparticles presented huge enhancement in two-photon photoluminescence signal in comparison with two other nanoparticles. Moreover, the gold@silver@gold nanoparticle is a stable and biocompatible plasmonic nanosystem. This paper provides a novel candidate for two-photon photoluminescence excitation sensing and imaging for biomedical applications.

Governing factors for preparation of silver nanoparticles using droplet-based microfluidic device.

Droplet-based microfluidic devices are now more than ever used for the synthesis of nanoparticles with low polydispersity and well-defined properties suitable for various industrial applications. Very small reaction volumes (microlitre to femtolitre) and short diffusion lengths, provide superior mixing efficiency and heat transport. Both play the dominant role in case of ultra-fast chemical reactions triggered upon reactant mixing, e.g. preparation of colloidal silver by reduction of silver salt. The high sensitivity of these systems to process variables makes otherwise more straightforward batch-wise production prone to suffer from inconsistency and poor reproducibility, which has an adverse effect on the reliability of production and further particle utilisation. This work presents a rigorous description of microfluidic droplet formation, reactant mixing, and nanoparticle synthesis using CFD simulations and experimental methods. The reaction mixture inside of droplets was homogenized in less than 40 milliseconds, which has been confirmed by simulations. Silver nanoparticles produced by droplet-based microfluidic chip showed superior to batch-wise preparation in terms of both particle uniformity and polydispersity.

Electrospun nanofibers of poly (acrylonitrile-co-itaconic acid)/silver and polyacrylonitrile/silver: In situ preparation, characterization, and antimicrobial activity

In this study, it was aimed to prepare silver nanoparticles by reduction of silver salt (AgNO3) in situ by means of only synthesized polyacrylonitrile (PAN) and poly(acrylonitrile-co-itaconic acid) (P(AN-co-IA)) polymers, and N,N dimethylformamide (DMF). Thereafter, PAN/Ag and P(AN-co-IA)/Ag nanofibers were prepared via electrospinning. Spectroscopic and morphologic characterizations, electrical and thermal features, and antimicrobial activities of the prepared nanofibers against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were carried out in detail. It was observed that P(AN-co-IA) was much more effective than PAN on the reduction of AgNO3 and formation of silver nanoparticles. Silver nanoparticles and also itaconic acid contributed to decrease the cyclization temperature of PAN by generating sharp exothermic peaks. In addition, electrical conductivity of the nanofibers increased dramatically from E−13 to E−4 related to the presence of silver nanoparticles. Furthermore, incorporation of silver nanoparticles to the nanofiber membranes let bactericidal/fungicidal activities, which started at 6–24 h and continued for up to 168 h, against S. aureus, E. coli, P. aeruginosa, and C. albicans. The prepared silver containing nanofibers can be regarded as good candidates for potential use in the biomedical and pharmaceutical applications.

Controlling self-assembly of ultra-small silver nanoparticles: Surface enhancement of Raman and fluorescent spectra

Resorcinol based reduction and capping of ultra-small colloidal silver nanoparticles (Ag NPs) optimally formed hydrogen bond driven clusters within the water-based solution. Large-area self-assembled fractal structures of Ag NPs aggregates were fabricated by solvent evaporation technique on silicon substrate. The final dried surface structures were found to be pH dependent which was adjusted to particular values after the optimal reduction of silver salt, capping of Ag NPs, followed by cluster formation at an optimum pH in the solution phase. These self-assembled surface structures show controlled enhancement of various surface optical phenomena such as Raman spectra of a model dye and luminescence of Ag NPs as a function of pH dependent fractal dimension of the resulting structures. The structure, morphology and various relevant optical properties of self-assembled fractals of Ag NPs were further established by combined use of X-Ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-Visible, photoluminescence and Raman spectroscopy analysis.