Silver Dendrites Research Articles

Dendritic silver self-assembly in molten-carbonate membranes for efficient carbon dioxide capture

Self-assembling Ag dendritic networks provide ultrahigh CO2 permeability, whilst reducing membrane-volume-normalised Ag demand by an order of magnitude.

Sensitive voltammetric sensor based on silver dendrites decorated polythiophene nanocomposite: Selective determination of L-Tryptophan

This present work describes the direct electrochemical determination of L-Tryptophan (L-Try) using polythiophene (PT) with silver (Ag) dendrites composite formed via electrostatic interaction. In the composite, Ag dendrites provide the energy to speedup chemical reaction by the presence of cationic free radicals and found attached with the backbone of PT. Furthermore, the sulfur groups of PT help in the formation of a stable product, and keeping them in same phase. The PT-Ag modified Glassy Carbon Electrode (GCE) revealed excellent electrochemical activity towards the oxidation of L-Try with the linear response in the concentration range of 200 nM–400 μM with detection limit of 20 nM. The fabricated sensor demonstrated the selective determination of L-Try in presence of foreign substances and the PT-Ag modified interface lead to the development of novel biosensor with high sensitivity and good stability which is mainly attributable to increased surface area of the composite. The characteristics of the PT-Ag hybrid nanocomposite proved the determination of L-Try in real food samples like soybeans extract with satisfactory results.

Self-organized spatially separated silver 3D dendrites as efficient plasmonic nanostructures for surface-enhanced Raman spectroscopy applications

Surface-enhanced Raman spectroscopy (SERS) is a promising optical method for analyzing molecular samples of various nature. Most SERS studies are of an applied nature, indicating a serious potential for their application in analytical practice. Dendritelike nanostructures have great potential for SERS, but the lack of a method for their predictable production significantly limits their implementation. In this paper, a method for controllably obtaining spatially separated, self-organized, and highly-branched silver dendrites via template synthesis in pores of SiO2/Si is proposed. The dendritic branches have nanoscale roughness, creating many plasmon-active “hotspots” required for SERS. The first held 3D modeling of the external electromagnetic wave interaction with such a dendrite, as well as experimental data, confirms this theory. Using the example of a reference biological analyte, which is usually used as a label for other biological molecules, the dendrites’ SERS-sensitivity up to 10−15M was demonstrated with an enhancement factor of 108. The comparison of simulation results with SERS experiments allows distinguishing the presence of electromagnetic and chemical contributions, which have a different effect at various analyte concentrations.

Direct synthesis of singular silver dendrites over TiO2 nanotubes using pentetic acid as capping agent

Silver dendritical nanostructures are known for their interesting electronic and optical properties compared to other Ag morphologies, vastly utilized for covering TiO2 nanotubes. However, multiple steps are required to assemble both of these structures. This paper reports a novel synthesis of vertically aligned TiO2 nanotubes covered by a forest of silver dendrites, obtained through the incorporation of electrodeposition (ED) cycle before the anodization process. Utilizing pentetic acid as a capping agent promotes superficial silver nucleation in both ED and anodization cycles. Also, testing varied ED cycle lengths provided information regarding the morphological evolution of the hierarchical silver structures, as some branches adopted a 90° angle from the central axis.

Dendronized Silver Nanoparticles as Bacterial Membrane Permeabilizers and Their Interactions With P. aeruginosa Lipopolysaccharides, Lysozymes, and Phage-Derived Endolysins.

Antimicrobial proteins, like lysozymes produced by animals or bacteriophage lysins, enable the degradation of bacterial peptidoglycan (PG) and, consequently, lead to bacterial cell lysis. However, the activity of those enzymes is not satisfactory against gram-negative bacteria because of the presence of an outer membrane (OM) barrier. Lytic enzymes can therefore be combined with membrane-disrupting agents, such as dendritic silver nanoparticles. Nevertheless, a lipopolysaccharide (LPS), especially the smooth type, could be the main hindrance for highly charged nanoparticles to get direct access to the bacterial OM and to help lytic enzymes to reach their target PG. Herein, we have investigated the interactions of PEGylated carbosilane dendritic nanoparticles with P. aeruginosa 010 LPS in the presence of lysozymes and KP27 endolysin to find out the main aspects of the OM destabilization process. Our results showed that PEGylated dendronized AgNPs overcame the LPS barrier and enhanced the antibacterial effect of endolysin more efficiently than unPEGylated nanoparticles.

Simulation and synthesis of silver dendritic nanostructures for surface-enhanced Raman scattering

Silver dendritic nanostructures (AgD) is investigated for surface-enhanced Raman scattering (SERS) with simulation and experiments, the simulations showed that there is a significant absorbance over a broad spectrum from the AgD, this indicated that AgD is a good candidate for SERS. The simulations helped to study the parameters of the AgD that affects the SERS and we applied these simulation results for experimental designs, in which our experimental results of synthesis and characterization results of Raman spectrum showed consistence with the simulation results. These simulation results are very helpful in deciding the experimental parameters for efficient and effective synthesizing and reproduction of hierarchical silver dendritic nanostructure. The AgD were produced using displacement redox reaction between AgNO3 solution and Copper foil. We found that the concentration of AgNO3 played major role on the rate of reaction, and the rapid growth of the silver nanostructures was observed as the reaction time increases. The structural and morphological evolution of silver dendrites was examined with Scanning Electron Microscope (SEM). The Raman enhancement of AgDs was evaluated using Elman's reagent (DTNB) and Rhodamine 6G (R6G). The silver dendrites have great potential for diverse sensing applications ranging from food safety control, environmental monitoring and assessment, forensic investigation, and to medical diagnosis.

Nanostructured silver dendrites for photon-induced Cysteine dimerization

Under a controlled adsorption environment, L-cysteine molecules can be chemically adsorbed to the dendritic silver (Ag-D) surface by electrochemical methods with different functional groups. It is verified by surface-enhanced Raman spectroscopy that under alkaline conditions (pH = 13.50), the two functional groups of thiol and acid are simultaneously adsorbed on the surface of Ag-D, while NH2 is far from the surface; under acidic conditions (pH = 1.67), adsorption behavior suggests that both NH3+ and COO− are oriented toward the Ag-D surface, and that SH is far from the surface. The structure of L-cysteine adsorption under acidic conditions can be further verified by the addition of an L-cysteine molecule through light-induced coupling reaction to form cystine. Finally, in-situ two-dimensional Raman scattering spectroscopy confirmed the feasibility and uniformity of the coupling reaction.

Fractal Silver Dendrites as 3D SERS Platform for Highly Sensitive Detection of Biomolecules in Hydration Conditions.

In this paper, we report on the realization of a highly sensitive and low cost 3D surface-enhanced Raman scattering (SERS) platform. The structural features of the Ag dendrite network that characterize the SERS material were exploited, attesting a remarked self-similarity and scale invariance over a broad range of length scales that are typical of fractal systems. Additional structural and optical investigations confirmed the purity of the metal network, which was characterized by low oxygen contamination and by broad optical resonances introduced by the fractal behavior. The SERS performances of the 3D fractal Ag dendrites were tested for the detection of lysozyme as probe molecule, attesting an enhancement factor of ~2.4 × 106. Experimental results assessed the dendrite material as a suitable SERS detection platform for biomolecules investigations in hydration conditions.

Dendritic Silver Microstructures as Highly Sensitive SERS Platform for the Detection of Trace Urea

In this communication, Surface-Enhanced Raman Scattering (SERS) coupled with Ag dendrites has been firstly used for the detection of limited urea. Dendritic silver microparticles are immobilized on indium doped tin oxide (ITO) surface via replacement reaction, and the formation mechanism could be attributed to electroless deposition (ELD) and diffusion-limited aggregation (DLA), respectively. The plot of the average Raman intensity measured at 1004cm−1 as a function of urea concentration with R2 value of 0.999 indicates silver dendrites exhibit a satisfactory and consistent performance with an analytical urea enhancement. The limit of detection for urea could reach the physiological range of urea.

Surface-enhanced ZnS:Ag quantum dots scintillator

Surface-enhanced ZnS: Ag quantum dots scintillator has been manufactured by coupling quantum dots and dendritic silver surface-enhanced substrates. Four-fold enhancement of the fluorescence intensity was achieved compare to the undoped quantum dots without surface-enhanced substrates. Two silicon layers of certain thickness were used to prevent quenching of the fluorescence by monitoring the distance between quantum dots and surface-enhanced substrates. The enhancement results show consistence with theories, and larger enhancement factor is possible to be obtained with optimal preparation procedure. This study suggests a new method to achieve high performance quantum dots scintillator beneficial to radiation detection applications.

Investigation of Metallic Dendrite Growth in Electrolytes

The formation of the metallic dendrite in the electrolyte under electrolytic mode can contribute to the failure of the battery, which may result in dramatic fires. Under electrolytic conditions often degradation occurs which manifests as electrode delamination and formation of cracks. In this work, both solid and liquid electrolytes were used to investigate the in-situ metallic dendrite growth. Sodium sulfur batteries have been widely used for energy storage. Also, sodium ion batteries operating at room temperature are under development. One of the modes of failure of these devices is the formation of metallic sodium dendrites. In this work, a two-phase material Na-β”-alumina+3YSZ has been used to investigate the sodium dendrite growth under electrolytic conditions. The mixed Na+ ion and O2- ion electrolyte was fabricated by the vapor phase process. The sample was sintered and converted with an embedded hole, which was achieved by a wax coated copper wire during the initial uniaxial pressing stage. Subsequently, a small plastic tube with 1M NaNO3 solution was put on the surface of the obtained disc. Silver wires were put into the NaNO3 solution and the embedded hole, they were connected with an amperemeter, a resistor, and a voltage generator. The disc was put under the microscope, and a voltage of 3.5V was applied. In-situ formation of sodium dendrites was observed. The current response and the voltage between the sample were recorded, and EIS was measured every 20 min. Furthermore, the silver nitrate solution was used to investigate the formation of sharp silver dendrites. Several drops of silver nitrate solution were placed onto the surface of the glass slide, and a cover glass was used for protection. Two silver wires were immerged inside of the solution. By applying the voltage, the silver dendrites shoot out from the tip of the silver wire and also grow along the silver wire. The current response and voltage between the sample were recorded. EIS was measured every 10 min to get the Nyquist plots.

Facile and High-Yield Replacement Reaction-Assisted Synthesis of Silver Dendrites by Jet for Conductive Ink.

Metallic dendrites with uniform morphology, high purity, and large yield remain challenging to synthesize. In this work, single-crystalline silver (Ag) dendrites with uniform morphology, high purity, and large yield are successfully synthesized by employing single replacement reaction between aqueous silver nitrate (AgNO3) and solid copper (Cu) by jet. The combined effect of diffusion-limited aggregation and the locally oriented attachment of Ag particles is responsible for the formation of silver dendrites under nonequilibrium conditions. Finally, the potential applications of as-synthesized silver dendrites are demonstrated by successfully preparing silver-based conductive ink for flexible electronics and wearable equipment. The conductive pattern exhibits resistivity of 7.2 μΩ·cm, showing good conductivity of the prepared conductive material. This facile and time-efficient synthetic route can be extended to synthesize other noble metal nanostructures with desired morphologies by adopting selective precursor salt concentrations and substrate metals with proper redox potentials.

Thermoreversible Fibrous Hydrogel of Benzene‐Centered Tris‐dodecylimidazolium Bromide: A Dual Role as Stabilizer and Directing Agent for Silver Dendrites.

AbstractBenzene centered tris‐alkylimidazolium bromide salts, denoted as BTIm(R)3Br3 ; where R=C12H25 and C14H29 have been prepared and structurally characterised. The hydrogelation ability and stabilizer role of these salts for the synthesis of silver nanoparticles (AgNPs) via chemical reduction method is described. A worth note that the BTIm(C12)3Br3 compound could lead a thermoreversible fibrous‐hydrogel in water, which plays a dual role as stabilizer and directing agent for silver dendritic nanostructures. While the partial‐hydrogel of BTIm(C12)3Br3 contributes silver nanospheres. The non‐gel solutions of BTIm(C12)3Br3 in dichloromethane, and BTIm(C14)3Br3 in water as stabilizers did not show control over the shape of AgNPs, and they lead mixed morphology. The experimental conditions, i. e. temperature, heating‐cooling process and the physical state of the stabilizer play a key role in the thermoreversible hydrogel and partial‐hydrogel control over the morphology of Ag nanostructures. Overall, the outcome of the present study provides new possibility for the use of thermoreversible fibrous gels to prepare Ag dendrites.

Dendritic silver hierarchical structures for anode materials in Li ion batteries

Dendritic silver hierarchical structures were prepared via a simple electrochemical deposition method in the presence of citric acid. The influence of the molar ratio of citric acid and AgNO3, the deposition time and the deposition current on the crystalline and morphology of the products were studied by X-ray diffraction and scanning electron microscopy. Dendritic silver hierarchical structures consist of a long trunk with secondary branches, which grew in a parallel direction with a definite angle to the trunk. The average diameter of the trunk is 230–320 nm, that of the secondary branches is about 250 nm and the length of the branches is about 850 nm. The charge specific capacity of dendritic silver hierarchical structures was stable at around 250 mAh g−1 after 500 cycles at 0.1C. They also exhibited excellent rate capability at the various current rates from 0.1 to 5C.

Introduction of copper ions to regulate silver nanostructures by galvanic displacement reaction

Although the regulation of silver nanostructures has been reported a lot, there are few reports on the simple green preparation method of ultra-long silver nanobelts and the formation mechanism of silver nanostructures is not uniform. In this paper, ultra-long silver nanobelts and dendrite silver were synthesized through a galvanic displacement and the growth mechanism of the silver nanosturture were investigated in detail. In the primary battery reaction, the introduction of copper ions could change the electric double layer and then affected the growth of silver nanosturcture. Different concentration of copper ion lead to different silver nanostructures. The greater the concentration of copper ions, the more the silver nanostructures grow in three dimensions.

A screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin for voltammetric sensing of nitrite.

A disposable sensor is described for the determination of nitrite. A screen printed carbon electrode (SPCE) was modified with a 3D lamellar nanocomposite prepared by one-step electrodeposition from dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin. The modified SPCE exhibits high electrocatalytic activity toward nitrite oxidation, typically at a working potential at around 0.76V (vs. Ag/AgCl). Sensitive and selective voltammetric detection of nitrite is demonstrated. The linear range extends from 1 to 2000μM, the detection limit is 0.24μM, and the sensitivity is 585.7μAmM-1cm-2. The method was applied to the determination of nitrite in (spiked) pickles. Graphical abstract Schematic presentation of fabrication of a screen printed carbon electrode modified with a lamellar nanocomposite containing dendritic silver nanostructures, reduced graphene oxide, and β-cyclodextrin. Graphical abstract contains poor quality of text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.We have provided the original format of graphical abstract in the attachment.

Braid solid-phase microextraction of polycyclic aromatic hydrocarbons by using fibers coated with silver-based nanomaterials in combination with HPLC with fluorometric detection.

Authors propose a novel braid support configuration for use in solid-phase microextraction (SPME) fibers. Two different braided supports (double and triple) were prepared and compared with the conventional single support configuration. Three kinds of silver-based nanomaterials that serve as coatings on these supports are described. They included silver dendrites, silver nanoparticles (AgNPs), and silver dendrites decorated with AgNPs (Ag-dendrites@AgNPs). They were prepared by electrodeposition, a layer-by-layer (LBL) method, and a hybrid strategy, respectively. Fibers were used in the direct-immersion (DI) mode of SPME. Five polycyclic aromatic hydrocarbons (PAHs) were studied as model analytes by DI-SPME when analyzing (spiked) underground waters. PAHs were further determined with high-performance liquid chromatography (HPLC) and fluorescence detection. The analytical performance of the fibers was compared to that of the commercial polydimethylsiloxane (PDMS) fiber of 100μm thickness. AgNPs obtained by LBL was the best coating and the double braid was the best support configuration. The configuration of the SPME support always played an important role independently on the coating material, being always beneficial the use of double-braids. Despite the low coatings volumes of the silver-based fibers compared to that of PDMS, the analytical features of the method were adequate. Figures of merit include: (a) limits of detection down to 20ng·L-1; (b) intra-day, inter-day, and inter-fiber precisions (expressed as RSDs) of <13%, <12%, and < 13%, respectively; and (c) adequate operational lifetime (>60 extractions). Graphical abstract Schematic presentation of braided solid-phase microextraction support configurations together with different silver-based nanomaterials as coatings.

Study of Safety of SiO2(Ag)–Si System by Cytoflourometric Method of Analysis of Reactive Oxygen Species and Cell Death in Culture

The potential ability of SiO2(Ag)–Si nanosystem to induce oxidative stress and death of human peripheral blood cells involving reactive oxygen species was studied using a double-color cytoflourometry method. This SiO2(Ag)–Si system with silver dendrites obtained via the metal deposition into the pores of SiO2 template on a silicon substrate was shown to increase the concentration of ROS but not cause the cell death associated with oxidative stress. Such systems are prospective for the analysis of biological substances with Raman scattering.

Liquid-infused superhydrophobic dendritic silver matrix: A bio-inspired strategy to prohibit biofouling on titanium

Ti finds widespread opportunities in harsh seawater environment because of unique corrosion resistance. However, one tough challenge is the biofouling problem caused by the inherent friendliness to the attachment of biological organisms. In this study, a facile electrodeposition approach affords high driving force for crystal growth, and dendritic Ag has been constructed onto Ti substrate. After being modified with dodecanethiol vapor, superhydrophobicity is realized relying on the anchored hydrophobic moieties and the voids in dendritic Ag matrix. Superoleophilicity enables oil phase to drive out air in the matrix for finally achieving slippery liquid-infused porous surface (SLIPS) with high flatness and smoothness. Diatoms and green algae are used as the typical biofouling organisms to assay antifouling behavior of Ti covered by superhydrophobic (SHP Ti) and SLIPS surface (SLIPS Ti). After immersion for 14 days, the number of diatoms and green algae on bare Ti surface respectively reaches 1.60 × 1011 and 1.57 × 1011 cells/cm2. Meanwhile, for Ti covered by SLIPS, the cell density is only 6.84 × 107 cells/cm2 and 5.05 × 107 cells/cm2, decreasing to ca. 4 orders of magnitude smaller than that of bare Ti. For SHP Ti, its biofouling inhibition effect is lower than that of SLIPS Ti. Therefore, building SLIPS onto the surface has afforded a promising way for Ti to inhibit biofouling in seawater environment.

Fabrication of silver dendrite fractal structures for enhanced second harmonic generation and surface-enhanced Raman scattering

Here, we prepared silver (Ag) dendrite fractal nanostructures by a facile electrochemical deposition method. The silver dendrite fractal nanostructures exhibit multiple plasmon resonances, which leads to an enhanced second harmonic generation (SHG). Interestingly, the prepared thin film can be used as plasmonic substrates. As an example application, we selected surface-enhanced Raman scattering (SERS) spectroscopy with tunable sensitivity. Using 1,4-benzenedithiol (1,4-BDT) as a probe molecule, the SERS intensity of dendrite fractal nanostructures is approximately 77 times larger than that of the flower-like nanoplates (one of the structures that appears during the growth), and a low detection limit of 10−14 M 1,4-BDT can be achieved. Our results offer a low-cost and easy strategy in fabricating nonlinear photonic nanodevices and SERS chips.