Silver Dendrites Research Articles

Integration of bifunctional silver dendrite membranes with surface-enhanced Raman scattering for sensitive detection of polystyrene microplastics in aquatic environments

Microplastics (MPs) are emerging environmental pollutants that are present in aquatic environments and accumulate within the food chain, posing significant threats to human health. Over 8 million tons of MPs enter these ecosystems annually. However, existing rapid qualitative and quantitative analytical methods for trace MPs are limited, hindering comprehensive research on their impact in water environments. This study presents a novel composite membrane with both adsorption and filtration functions, integrated with surface enhanced-Raman scattering technology for detecting trace MPs in water. The silver dendrites, modified with n-hexanethiol and loaded onto filter paper, facilitate enhanced enrichment and simultaneous sensitive detection of MPs. The composite membrane exhibited excellent retention rates for standard polystyrene (PS) MPs of various sizes (200, 500, and 1000 nm), achieving high enrichment efficiency. Sensitive detection was realized with a linear response in a concentration range of 0.01 to 0.5 g/L, yielding optimal enhancement factors exceeding 2.92 × 103, enabling detection at μg/L levels. Recovery rates for PS in spiked environmental water samples ranged from 96.86 % to 102.96 %. This innovative method offers a promising approach for the rapid and sensitive detection of trace MPs in aquatic environments, contributing significantly to the assessment of MPs pollution.

Comparison of Survivin Determination by Surface-Enhanced Fluorescence and Raman Spectroscopy on Nanostructured Silver Substrates.

Survivin belongs to a family of proteins that promote cellular proliferation and inhibit cellular apoptosis. Its overexpression in various cancer types has led to its recognition as an important marker for cancer diagnosis and treatment. In this work, we compare two approaches for the immunochemical detection of survivin through surface-enhanced fluorescence or Raman spectroscopy using surfaces with nanowires decorated with silver nanoparticles in the form of dendrites or aggregates as immunoassays substrates. In both substrates, a two-step non-competitive immunoassay was developed using a pair of specific monoclonal antibodies, one for detection and the other for capture. The detection antibody was biotinylated and combined with streptavidin labeled with rhodamine for the detection of surface-enhanced fluorescence, while, for the detection via Raman spectroscopy, streptavidin labeled with peroxidase was used and the signal was obtained after the application of 3,3',5,5'-tetramethylbenzidine (TMB) precipitating substrate. It was found that the substrate with the silver dendrites provided higher fluorescence signal intensity compared to the substrate with the silver aggregates, while the opposite was observed for the Raman signal. Thus, the best substrate was used for each detection method. A detection limit of 12.5 pg/mL was achieved with both detection approaches along with a linear dynamic range up to 500 pg/mL, enabling survivin determination in human serum samples from both healthy and ovarian cancer patients for cancer diagnosis and monitoring purposes.

Enhanced SERS performance of cavity-hosting silver dendrites grown over TiO2 nanotubes

Silver nanostructures, utilized as SERS substrates, consistently exhibit exceptional performance in detecting organic compounds through Raman spectroscopy, primarily due to the electromagnetic enhancement mechanism. This study explores an advanced SERS substrate composed of cavities formed by silver dendrites (Ag-Ds) on TiO2 nanotubes (TiO2-NT), demonstrating exceptional performance in detecting organic compounds through Raman spectroscopy. TiO2-NT acts as a template, guiding the nucleation and growth of Ag-D to create the cavity structures. The deposition time of silver significantly influences substrate performance in detecting Rhodamine 6G (R6G) and Ibuprofen (IB). It has been observed that an extended deposition time diminishes the enhancement factor. In contrast, a shorter deposition time yields notable enhancement due to the combined effects of electromagnetic and chemical enhancement mechanisms. An optimum deposition time limits dendrite growth, forming cavities where the electric field couples with multiple light reflections, further amplifying the SERS enhancement. The cavity-hosted Ag-D/TiO2-NT substrate achieves an impressive analytic SERS enhancement factor of up to 2 × 109, enabling the detection of R6G and IB at a low detection limit of 10-12 M.

Mechanism and experimental study of in situ metallization on the surface of silver ion conductive glass

AbstractIn situ metallization of Ag+ conductive glass was successfully achieved by applying electric and temperature fields to the glass to ensure the controlled migration of ions inside the glass. The transport and kinetic characteristics of Ag+ under the combined effect of electric field and temperature field were investigated by calculating and analyzing Ag+ diffusion coefficient. The correlations between ion transport and current were characterized with potential energy equations. The simulations and experiments of ion transport in the conducting glass were implemented, which revealed the mechanisms of ion transport and interfacial precipitation within the conducting glass. Further more, the existence of Ag+ deprivation layer was confirmed and it was clarified that the depth of the deprivation layer reached 30 µm under thermal polarization conditions of 60 V and 300°C. The microscopic morphology of in situ silver deposition layer was observed using SEM and TOF–SIMS. In addition, It was determined that the in situ metallization of conductive glass under the polarization condition of 60 V at 250°C was the best, and the thickness of deposited silver dendrites reached 1000 nm in the side of cathodically. This paper provides theoretical and experimental references for the optimization of the in situ metallization process for the ion conductive glass.

Assembly of stabilized dendritic magnetic ferric-silver nanocomposite with gold nanoparticles for sensitive detection of ochratoxin A using SERS aptasensor

Ochratoxin A (OTA) contamination poses a significant global threat to food security, necessitating the development of rapid and effective detection methods. A dendritic magnetic silver nanocomposite (Fe3O4@SiO2@Ag) tagged with aptamers acted as surface-enhanced Raman scattering (SERS) substrates and capture probes. Further, gold nanoparticles (AuNPs) were functionalized with cDNA and utilized as Raman-enhanced probes (cDNA-AuNPs). The SERS aptasensor which was constructed by the assembly of Apt-Fe3O4@SiO2@Ag and cDNA-AuNPs attained the accuracy quantitative and extremely sensitive detection of OTA. An inverse relationship between the concentration of OTA standard solution and Raman intensity of the characteristic peak at 1080 cm−1 was established in the range of 0.01–5 ng/mL, with an LOD of 0.0074 ng/mL. Furthermore, for positive corn samples, the coincidence rate between the established SERS aptamer sensor and HPLC was in the range of 92.67–121.10%, demonstrating tremendous promise for future practical application through other crops.

Silver Dendrites Decorated AAO Membrane for SERS Sensing of Lactic Acid in Artificial Sweat

Silver Dendrites Decorated AAO Membrane for SERS Sensing of Lactic Acid in Artificial Sweat

Fabrication of CNT-supported dendritic silver nanocomposites for efficient electrochemical detection of breast cancer biomarker

Breast cancer is a fatal disease arising worldwide with an extensive high mortality rate. Monitoring and early detection of the biomarkers of the cancer can be a medium to restrain it from being lethal. The present study investigates the synthesis of carbon nanotubes (CNTs) supported copper dealloyed silver nanocomposite modified novel biosensor for superior electrocatalytic performance towards histidine (His); a biomarker of breast cancer (BC). The fabrication method employs electrochemical deposition of copper-silver (Cu-Ag) alloy on the CNT-modified probe (CuAg/CNT//GCE alloy) and subsequent dealloying of the elemental Cu leading to the development of dealloyed Ag/CNT//GCE sensor. The impact of the fabrication procedure enabled the proposed sensor to exhibit ∼ 1.7 and ∼ 2.27 folds higher electrocatalytic response than CuAg/CNT//GCE alloy and other modified electrodes, respectively. The amperometric response of the dealloyed Ag/CNT//GCE displays two moderate dynamic ranges within (i) 0.5 – 20 μM with a detection limit (LoD) of 0.48 μM (S/N = 3), and (ii) 20 – 500 μM with a LoD of 1.04 μM for His. A high anti-interference ability of the modified probe is also noticed towards different amino acids. Finally, the proposed sensor has been tested for determination of His in real samples, with satisfactory recovery results. The precision and comprehensive performance justify the sensor to be a potential candidate for monitoring clinical projects.

Eu-doped chitosan carbon dot/dendritic silver nanostructure-based biosensor for BRAF detection in thyroid cancer exosome

In this work, a novel electrochemiluminescence (ECL) biosensor has been constructed with Eu-doped chitosan carbon dot (Eu: Cs dot) and dendritic silver nanostructure. Firstly, Eu: Cs dots were synthesized as ECL tags, which not only possessed exceptional electrochemical characters and intense luminescence, but also can reacted with H2O2 as co-reactant to generate ECL signal. Furthermore, dendritic silver nanostructure with conductive gel was successfully prepared as sensing interface. The dendritic silver nanostructure with conductive gel displayed the ideal conductivity, good electrochemical stability, which can enhance the ECL intensity of Eu: CS dots. Finally, BRAF V600E from thyroid cancer exosome in the clinic eluate can be captured and detected. The results indicated the relative association between BRAF V600E mutation and lymphatic metastasis, which can be used in assessing thyroid cancer progression for advancing clinical diagnosis applications.

Silver Dendrite‐Coated Silicon Pyramid Substrate as Surface‐Enhanced Raman Scattering Probe for Detecting Glucose

Raman spectroscopy offers a rapid and nondestructive method for qualitatively and quantitatively analyzing the molecular structure of substances. Herein, a facile and cost‐effective approach for the preparation of three‐dimensional (3D) surface‐enhanced Raman scattering (SERS) substrates is proposed, in which pyramid structures are fabricated using silicon anisotropic wet etching and silver dendrites are decorated on these silicon pyramid (PSi) substrates by immersing them in a mixture of hydrofluoric acid and silver nitrate for several minutes. The 3D SERS substrates, based on PSi coated with Ag dendrites, reveal high‐performance SERS enhancement (with an analytical enhancement factor reaching 3.54 × 1010) and can detect rhodamine 6G (R6G) in the presence of chemical enhancer (lithium chloride) at low concentrations down to 10−11 m. For glucose detection, 2‐thienylboronic acid is employed to faciliate glucose attachment to the substrate surface, achieving a detection limit as low as 10−6 m. The substrate exhibits good repeatability with a relative standard deviation of 11.223%, as well as reusability and long‐term stability for detection. The results also highlight the excellent sensitivity of the PSi‐based SERS substrate, which is expected to be instrumental in biochemical analysis and holds significant potential for developing noninvasive glucose sensor for diabetic patients using saliva samples.

Effects of Antifoaming Agents on Manufacturing Silver Dendrites Through Fluoride-Assisted Galvanic Replacement Reaction

Abstract In fluoride-assisted galvanic replacement reaction (FAGRR), metallic dendrites are formed simultaneously with hydrogen gas. However, the presence of hydrogen bubbles impedes the reduction of metallic ions to form metallic dendrites. This study investigates the FAGRR approach to manufacturing Ag dendrites where ethanol is incorporated into an AgNO3 reaction solution. The findings of this study demonstrate the efficacy of ethanol as an antifoaming agent in enhancing the deposition of the Ag dendrites during the FAGRR process. The antifoaming effect of ethanol becomes more intense at higher concentrations of AgNO3. The introduction of ethanol into FAGRR can significantly improve processing efficiency and yield in the limited time for manufacturing science and engineering.

Electrodeposited Silver Dendrites on Laser‐Induced Graphene for Electrochemical Detection of Nitrate with Tunable Sensor Properties

AbstractLaser‐induced graphene (LIG) is a promising technology enabling cost‐effective, scalable, and high surface area 3D‐porous graphene electrodes for electrochemical applications. Nitrate in water bodies is a harmful contaminant to humans and the ecosystems. Its detection by electrochemical sensors is challenging due to the interference from nitrite. Herein, for the first time, a LIG‐based electrochemical sensor modified with electrodeposited silver dendrites (EdAg/LIG) without using surfactants is proposed for the detection of nitrate with tunable selectivity and sensitivity. The modified electrode surface is extensively characterized by spectroscopic and electrochemical methods and the underlying mechanism for the formation of dendrites is substantiated. The developed EdAg dendrites/LIG electrode shows excellent sensing properties for the detection of nitrate at pH 2. The interference with nitrite in acidic media is eliminated by implementing a novel strategy to shift the working pH of the electrode to 7. The achieved sensor properties at both pH values surpass other LIG‐based sensors with limit of detection of 0.46 at pH 2 and 5.53 µm at pH 7. The developed sensor also shows good recovery characteristics in mineral, tap, and groundwater across a wide range of concentrations and also demonstrates good stability under temperature fluctuations and deformations.

Room temperature synthesis and hydrophobic surface protection of silver dendrites for hydrogel stretchable sensors

Hydrogel stretchable sensors have gained increasing popularity as essential components for next-generation flexible electronics. Stringent standards have been placed on the cost, conductivity, stability, and sensitivity of composites. In this work, highly conductive silver dendrites with uniform morphology were successfully synthesized by galvanic displacement reaction. Due to the more complex three-dimensional structure of the silver dendrites, the percolation threshold of the conductive composites was reduced to approximately 45 wt%. By decorating the as-prepared silver dendrites with a dense and hydrophobic dodecanethiol layer, the issue of hygrothermal stability in the hydrogel matrix has been successfully addressed. Silver dendrites conductive composites exhibited excellent electrical conductivity (8.57×10−4Ω∙cm for 65 wt% silver dendrites) and sensing properties. The stretchable conductors exhibited high sensitivity and linearity with F= 9.48 and R2= 0.9967. Therefore, human-computer interaction was successfully carried out by monitoring the movement of fingers, wrists, elbows, and knees of the human body.

Silver dendrite metasurface SERS substrates prepared by photoreduction method for perfluorooctanoic acid detection

Perfluorooctanoic acid (PFOA), a novel organic pollutant, has been shown to be toxic, persistent, bioaccumulative, long-range transportable, and globally prevalent. This article is based on surface enhanced Raman scattering (SERS) spectroscopy analysis technology. The monolayer of SiO2 was prepared by chemical reduction etching self-assembly method and silver dendrites were grown on it, thus forming the SERS substrate with silver dendrite Metasurface structure with Raman detection enhancement factor up to 2.32 × 105. The prepared silver dendrite Metasurface SERS substrate was applied to the qualitative and quantitative detection of PFOA, with a quantitative detection limit of 15.89 ppb. The results of this paper provide a new, simple, and quick method for the detection of PFOA in the environment.

The Roughness Effect on the Preparation of Durable Superhydrophobic Silver-Coated Copper Foam for Efficient Oil/Water Separation

In recent decades, there has been a significant interest in superhydrophobic coatings owing to their exceptional properties. In this research work, a superhydrophobic coating was developed on copper foams with a different roughness via immersion in AgNO3 and stearic acid solutions. The resulting foams exhibited water contact angles of 180°. Notably, surface roughness of the substrate influenced the development of silver dendrites and stearic acid morphologies, leading to different structures on rough and smooth copper foams. Separation efficiency was maintained above 94% for various pollutants, suggesting good stability and durability, irrespective of the substrate’s roughness. Conversely, absorption capacity was influenced by surface roughness of the substrate, with smooth copper foams demonstrating higher absorption values, primarily due to its uniform porosity and microstructure, which allowed for efficient retention of pollutants. Both copper foams exhibited excellent thermal and chemical stability and maintained their hydrophobic properties even after a 40 h exposure to harsh conditions. Mechanical durability of modified copper foams was tested by dragging and in ultrasounds, exhibiting promising results. The samples with the smooth substrate demonstrated improved coating stability.

A phase-field model of electrochemical migration for silver-based conductive adhesives

Electrochemical migration failure is the main reliability problem that silver conductive adhesives face in the field of power electronics. However, there is no prior existing study that describes the electrochemical migration process of silver conductive adhesive using the phase-field model. In this study, a phase-field model is proposed to study the electrochemical migration process of silver-based conductive adhesive. The model involves the analysis of electrochemical reactions, diffusion of metal ions, applied electrode potential and overpotential and the morphology of electrochemically migrating dendrites. Model-building is based on the water drop (WD) test of silver conductive adhesive. The simulation results of the phase-field model not only reproduce the morphology of the silver dendrite, but also realize the critical voltage phenomenon in the WD experiments. In addition, by comparing the results of WD experiments as well as the model simulations, we demonstrate that the phase-field model is able to predict the electrochemical migration failure time of silver conductive adhesives effectively. The proposed model may be a helpful tool for understanding and predicting the evolution of dendrites during the electrochemical migration of silver-based conductive adhesives.

Flower-like nanocomposite of carbon quantum dots, MoS2, and dendritic Ag-based Z-scheme type photocatalysts for effective tartrazine degradation

Nanocomposites of carbon quantum dots, molybdenum disulfide, and dendritic silver (MoS2/CQD/dendritic Ag) were synthesized via a facile and inexpensive procedure and utilized to investigate photocatalytic degradation of tartrazine (TZN) in aqueous medium. The nanocomposites and their individual components were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), mapping, X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The optimum conditions for TZN degradation obtained were TZN concentration of 20 mg/L and a solution pH of 6.5. Electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) analysis were employed to evaluate the TZN degradation by the prepared MoS2/CQD/dendritic Ag nanocomposites. XRD of CQDs, MoS2 and Ag NPs showed amorphous, hexagonal phase and face-centered cubic structures, respectively. Band gaps of 3.3 and 1.9 eV for CQDs and MoS2, respectively as obtained from UV–Vis DRS.The enhanced photo-degradation of TZN was achieved due to the synergistic effects between the nanocomposite constituents. Complete degradation of TZN occurred within 30 min with a rate constant value of 0.172 min−1, wherein oxygen radicals played a significant role compared to other species during the process of degradation.

Tunable and highly accessible plasmonic gap nanostructures on flexible film as a high-performance surface-enhanced Raman scattering sensor

Tunable plasmonic gap nanostructures on flexible substrates have been considered as an evolutionary development in diverse fields. The size-controllable nano-gaps can process optical signals on the deep nanoscale to provide optimal and strong signal generation in a spatially controlled manner and flexible devices can realize rapid analysis, easy operation and cost-effectiveness. In addition, the creation of a number of exposed and vacant nano-gaps on flexible materials is essential for target molecules to diffuse into the nano-gaps. However, it remains challenging to synthesize a structure that satisfies these requirements. Herein, we present size-controllable, unoccupied, and exteriorly exposed nano-gaps on a flexible plasmonic sensor; control of the signal amplification ability is realized by changing the nano-gap distance. We prepared a graphene modified polyimide film and silver dendrites structures were electro-deposited. Then, secondary protruding gold nano-islands were deposited on silver dendrites via galvanic replacement. Controlling the morphology of gold nano-islands with different sizes and densities yielded different nano-gap lengths of 3–30 nm between the gold nano-islands in a controlled manner. It was achieved by manipulating the amount of injected gold precursor, reaction time, and solvent volume. Therefore, it was possible to control the degree of Raman signal enhancement with respect to the diminished nano-gap length. Benefiting from direct contact with the target area and the free diffusion of surrounding molecules to the void nano-gaps, this flexible plasmonic sensor was successfully used as a potent surface-enhanced Raman scattering sensor for monitoring the trace-amounts of a drug molecule on an arbitrary curved surface.

Electrolytic Synthesis and Tolyltriazole Modification of Dendritic Silver Powders for High‐performance Electrically Conductive Adhesives

AbstractDendritic silver particles (DSPs) were synthesized by a facile electrolysis method based on the self‐made silver methanesulfonic as an electrolyte and the surface of DSPs was coated with methyl‐1H‐benzotriazole to prepare the surface‐modified DSPs. Dendritic feature with a trunk and nano‐branches is confirmed by scanning electron microscopy. At temperatures above 200 °C, the sintering phenomenon is discovered at the nano‐branches of DSPs. As the prepared DSPs are introduced into the commercial micron‐scale silver particles‐based electrically conductive adhesives (ECAs), the electrical resistivity can be significantly reduced to 5.63×10−5 Ω cm, which is superior to the traditional conductive adhesives derived from the pure micron‐scale silver particles, implying the high application value of DSPs for high‐performance conductive adhesive.

Biological Response Evaluation of Human Fetal Osteoblast Cells and Bacterial Cells on Fractal Silver Dendrites for Bone Tissue Engineering.

Prosthetic joint replacement is the most widely used surgical approach to repair large bone defects, although it is often associated with prosthetic joint infection (PJI), caused by biofilm formation. To solve the PJI problem, various approaches have been proposed, including the coating of implantable devices with nanomaterials that exhibit antibacterial activity. Among these, silver nanoparticles (AgNPs) are the most used for biomedical applications, even though their use has been limited by their cytotoxicity. Therefore, several studies have been performed to evaluate the most appropriate AgNPs concentration, size, and shape to avoid cytotoxic effects. Great attention has been focused on Ag nanodendrites, due to their interesting chemical, optical, and biological properties. In this study, we evaluated the biological response of human fetal osteoblastic cells (hFOB) and P. aeruginosa and S. aureus bacteria on fractal silver dendrite substrates produced by silicon-based technology (Si_Ag). In vitro results indicated that hFOB cells cultured for 72 h on the Si_Ag surface display a good cytocompatibility. Investigations using both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacterial strains incubated on Si_Ag for 24 h show a significant decrease in pathogen viability, more evident for P. aeruginosa than for S. aureus. These findings taken together suggest that fractal silver dendrite could represent an eligible nanomaterial for the coating of implantable medical devices.

Preparation of Spherical Ultrafine Silver Particles Using Y-Type Microjet Reactor.

Herein, micron-sized silver particles were prepared using the chemical reduction method by employing a Y-type microjet reactor, silver nitrate as the precursor, ascorbic acid as the reducing agent, and gelatin as the dispersion at room temperature (23 °C ± 2°C). Using a microjet reactor, the two reaction solutions collide and combine outside the reactor, thereby avoiding microchannel obstruction issues and facilitating a quicker and more convenient synthesis process. This study examined the effect of the jet flow rate and dispersion addition on the morphology and size of silver powder particles. Based on the results of this study, spherical and dendritic silver particles with a rough surface can be prepared by adjusting the flow rate of the reaction solution and gelatin concentration. The microjet flow rate of 75 mL/min and the injected gelatin amount of 1% of the silver nitrate mass produced spherical ultrafine silver particles with a size of 4.84 μm and a tap density of 5.22 g/cm3.