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A novel and simple trap technique combining a gold‐coated tungsten coil with hydride generation atomic absorption spectrometry (HGAAS) were developed for ultra‐trace lead determination. The technique was based on first transporting the plumbane produced by the HG system, together with H2, to a trap externally heated to 92 °C, where it was collected for in‐situ preconcentration and then volatilized by raising the trap temperature to 510 °C. For a 120 s trapping time, the limit of detection (LOD) was 2.9 ng L−1, the limit of quantification (LOQ) was 9.7 ng L−1 and the relative standard deviation was 3.1 % (at 0.02 μg L−1). The analytical performance of the technique was contrasted against the classical HGAAS method and a 39.2‐fold increase in sensitivity was obtained when comparing the characteristic concentrations of both methodologies. The morphology of the trap surface was also studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The accuracy of the proposed method was verified by analyzing the Pb concentration in the certified reference materials and the results agreed well with the certified values. Finally, the developed procedure was successfully applied to seawater samples and the recoveries of standard addition were between 102.4 % and 105.2 %. [ABSTRACT FROM AUTHOR]

Traditional chemiluminescence (CL) imaging immunoassays usually rely on natural enzymes as catalytic probes, which has hampered their extensive application due to the susceptibility to inactivation of natural enzymes. In response, a gold brocade coated CoFe Prussian blue analogue (CoFe PBA@Au brocade) with enhanced peroxidase-like activity was synthesized and utilized as a powerful label probe for constructing a highly sensitive CL imaging immunosensor targeting disease biomarkers with excellent performance. This research offers a universal strategy for enhancing the sensitivity of CL imaging immunoassays and further expands the application of PBA nanozymes. [ABSTRACT FROM AUTHOR]

In order to achieve a high-precision synchronous detection of two different refractive index (RI) analytes, a D-type surface plasmon resonance (SPR) photonic crystal fiber (PCF) RI sensor based on two channels is designed in this paper. The sensor uses a D-shaped planar region of the PCF and a large circular air hole below the core as the sensing channels. Surface plasmon resonance is induced by applying a coating of gold film on the surface. The full-vector finite-element method (FEM) is used to optimize the structural parameters of the optical fiber, and the sensing characteristics are studied, including wavelength sensitivity, RI resolution, full width at half maximum (FWHM), figure of merit (FOM), and signal-to-noise ratio (SNR). The results show that the channel 1 (Ch 1) can achieve RI detection of 1.36–1.39 in the wavelength range of 1500–2600 nm, and the channel 2 (Ch 2) can achieve RI detection of 1.46–1.57 in the wavelength range of 2100–3000 nm. The two sensing channels can detect independently or simultaneously measure two analytes with different RIs. The maximum wavelength sensitivity of the sensor can reach 30,000 nm/RIU in Channel 1 and 9900 nm/RIU in Channel 2. The RI resolutions of the two channels are 3.54 × 10−6 RIU and 10.88 × 10−6 RIU, respectively. Therefore, the sensor realizes dual-channel high- and low-RI synchronous detection in the ultra-long wavelength band from near-infrared to mid-infrared and achieves an ultra-wide RI detection range and ultra-high wavelength sensitivity. The sensor has a wide application prospect in the fields of chemical detection, biomedical sensing, and water environment monitoring. [ABSTRACT FROM AUTHOR]

Peri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis. Titanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) & Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD. The gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs. Ceramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments. [ABSTRACT FROM AUTHOR]

This work initially presents our progress in developing a 14 W all-polarization-maintaining (PM) Yb-doped fiber laser system. This system can generate bursts with a 2.8 GHz intra-burst repetition rate and offers flexibility in burst repetition rates, starting from 100 kHz. The laser produces pulse energies up to 210 nJ, which can be dechirped to approximately 650 fs. Subsequently, we utilized the developed laser in thin film gold processing. We sent up to 6.4 W and employed three different intraburst pulse configurations on a 100 nm-thick gold film coated on glass. We achieved a record gold removal efficiency of 125 μ g / W.s using ∼ 5 nJ pulses. Moreover, we determined an ablation pulse energy threshold of approximately 1 nJ, representing the lowest pulse energy to the best of our knowledge. [ABSTRACT FROM AUTHOR]

pH regulation in human biofluids is a crucial step for disease diagnosis and health monitoring. Traditional pH sensors are limited by their bulky size in wearable systems, and fragile glass tips require frequent calibration, thus limiting their use in continuous monitoring. Flexible sensors, particularly those utilizing microwires and thread-based substrates, present advantages for small sample analysis, including natural breathability and suitability for bandage or textile integration. This study examines iridium oxide and silver–silver chloride coated on thin gold wires, fabricated using sol–gel and dip-coating processes known for their simplicity. The flexible microwires demonstrated promising pH performance from a study of their pH characteristics, sensitivity, hysteresis, and potential drift. Electrodes tested in microwells allowed for small sample volumes and localized pH measurement in a controlled environment. Additional integration into fabrics for sweat sensing in wearables highlighted their potential for continuous, real-time health monitoring applications. [ABSTRACT FROM AUTHOR]

Nanoparticles that catalyze biochemically relevant reactions are promoted as alternative enzymes. The application of such artificial enzymes is severely restricted by poor selectivity in biological fluids; mainly because the reactions occur at active sites on the exterior surface of the nanoparticle. Enzymes in contrast typically have their active sites down a nanoconfined substrate channel where the reaction occurs in different solution conditions to bulk solution which aids in achieving selectivity for the substrate. Herein the same 3D structure of enzymes is mimicked in nanoparticles to allow selective reactions in biological fluids. This is achieved using a gold nanoparticle coated in a conducting mesoporous carbon shell where isolated nanochannels lead to the gold surface. It can detect glucose in whole blood with no interference from other species. This is achieved by electrochemically pulsing the artificial enzymes to generate the locally required alkalinity for an effective electrocatalytic reaction in the nanochannels, as well as expelling fouling agents that will otherwise passivate the electrocatalytic reaction. The artificial enzymes are shown to be capable of detecting glucose in biological fluids, without loss of signal, for several months. This study shows how nanoconfinement in nanoparticles can be exploited to potentially allow a broad range of species to be selectively detected in biological fluids with stability that can exceed that of enzymes. [ABSTRACT FROM AUTHOR]

Cuprous oxide nanoparticles can be prepared with a great morphological control, and their composites with gold nanostructures are intensively studied owing to their catalytic performance. In this study, cuprous oxide shell growth on nanosized prism‐shaped gold nanoparticles is investigated, where the core‐particle morphology does not match the prototypical cubic or octahedral symmetry of the embedding cuprous oxide particle. It is shown that different shell morphology is obtained depending on the reducing agent used for the shell deposition. Strong reducing agent (hydrazine) leads to a multi‐slab‐like coating with smooth facets, while under milder conditions (hydroxylamine) a multi‐grain coating is obtained. Successful realization of time‐dependent spectroscopic and structural investigations indicate that in this latter case cuprous oxide shell growth is initiated site‐selectively, namely in the highly curved regions of the particle, with a higher growth rate around the tips of the nanoprisms. This is supported by correlative single‐nanoparticle spectroscopy/scanning electron microscopy measurements, that allow to establish the connection between the optical properties and the structure of these plasmonic/semiconductor core/shell nanoparticles. [ABSTRACT FROM AUTHOR]

To facilitate the sensor fabrication and sensing operation in microstructured optical fiber-based surface plasmon resonance (SPR) sensors for high refractive index (RI) detection, we propose a special hollow fiber-based SPR sensor that comprises an opening on its body side and a thin gold layer coated on its outer surface. The analyte is able to flow into the hollow core through the side-opening to form new fiber core, with the Gaussian-like mode propagating in it. We investigate the sensing performance of the proposed sensor in a higher RI range of 1.48 to 1.54 at two feasible schemes: one is to only fill the fiber core with analyte (Scheme A), and the other is to directly immerse the sensor in the analyte (Scheme B). The results demonstrate that our sensor exhibits higher wavelength sensitivity at Scheme A with a maximum wavelength sensitivity of 12,320 nm/RIU, while a greater amplitude sensitivity was found at Scheme B with a maximum amplitude sensitivity of 1146 RIU−1. Our proposed sensor features the advantages of simple fabrication, flexible operation, easy analyte filling and replacing, enhanced real-time detection capabilities, high RI detection, and very high wavelength sensitivity and amplitude sensitivity, which makes it more competitive in SPR sensing applications. [ABSTRACT FROM AUTHOR]

Microbial contamination on surfaces is a problem worldwide, affecting public health and industry. The increasing prevalence and severity of microbial infection outbreaks across various environments have highlighted the urgent need to develop antimicrobial coatings/surfaces to mitigate the risk of disease transmission through high‐touched surfaces. This work focuses on assessing the antifungal activity of thin films based on zinc oxide (ZnO), produced by reactive magnetron sputtering with varying thicknesses, and evaluating the impact of varying gold concentrations within the ZnO matrix on both microstructure and antifungal activity. The developed thin films exhibit noteworthy antifungal activity against the fungus Candida albicans, achieving 80% reduction in cell viability, regardless of thickness and gold concentration (up to 15.4 at%). Annealing treatment at 600 °C induces the formation of large and irregular gold nanostructures (sizes from 39 to 260 nm), enhancing the antifungal activity compared to the as‐deposited samples. This highlights the surface‐dependent antifungal efficacy of ZnO‐based thin films and a synergistic effect when combined with gold. Additionally, the thin films not only exhibit antifungal activity but also demonstrate potential for localized surface plasmon resonance applications. Overall, ZnO‐based thin films hold promise as antifungal coatings for diverse surfaces, offering a preventive measure against microbial contamination. [ABSTRACT FROM AUTHOR]

Micro-Electromechanical-Relay (MER) has widely achieved application in the field of engineering thanks to the excellent features and ever-growing interest in microelectronic products. However, the adhesion phenomenon between gold-sputtered contact pairs in MER usually brings about operating failure of normally closed contacts limiting the reliability level of MER. In this paper, various contact combinations between electrical contact pairs are assembled to simulate real contact conditions, and associated failure type is built by taking advantage of mechanical adhesion theory to reveal failure mechanism about cold adhesion. It is found that the adhesion force is correlated closely with the surface roughness of contact pairs. The specific contact combination is a significant effective strategy to reduce the adhesion failure between electrical contacts. [ABSTRACT FROM AUTHOR]

In this work, we report the development and characterization of an atom chip for magnetic trapping of cold 87 Rb atoms. For fabrication of the atom chip, a silicon substrate was used after depositing an insulating layer of silica ( SiO 2) on it. An adhesive chromium layer was further deposited on this substrate before the deposition of the final layer of gold. On this gold coated substrate, a z-shaped gold wire (cross section, 500 × 2.5 μ m 2) was fabricated by a photo-chemical machining method. The chip wire was tested for current–voltage characteristics for its reliable operation in magnetic trapping. The atoms from an U-magneto-optical trap, after optical pumping, were directly trapped in the magnetic trap of the atom chip. [ABSTRACT FROM AUTHOR]

A dual-functional material was fabricated to mimic the periosteum for guided bone regeneration. Poly(vinylidene fluoride) (PVDF) was fabricated into a gold-coated electrospun membrane. The gold-coated PVDF membranes were observed and characterized for their morphology and structural formation using light microscopy and differential calorimetry, respectively. Hydrophilicity, mechanical behavior, and electrical properties were evaluated from the results of the contact angle, universal testing machine, and an inductance–capacitance–resistance meter, respectively. MC3T3E1 osteoblast cells were seeded onto PVDF membranes with and without the gold coating. The cells on the seeded membranes were cultured under either a non-dynamic condition or a dynamic condition by shaking at 100 rpm (1.67 Hz). In vitro testing was performed to evaluate the biological performance (cell proliferation and viability), protein analysis, alkaline phosphatase (ALP) activity, and calcium content. PVDF with the gold coating had a higher melting temperature, hydrophilicity, and dielectric constant than without the gold coating. The gold-coated PVDF membranes showed a lower Young's modulus than the uncoated PVDF membranes. The seeded gold-coated and uncoated PVDF membranes under the dynamic condition had higher cell proliferation, viability, protein amount, ALP activity, calcium content, and calcium deposition than the PVDF membrane without either the gold coating or under the dynamic condition. Finally, the results deduced that the gold-coated PVDF membranes were able to mimic the periosteum with a dual function and showed promise for guided bone regeneration. [ABSTRACT FROM AUTHOR]

Photothermolysis is the process that converts radiation energy into thermal energy, which results in the destruction of surrounding tissues or cells through thermal diffusion. Laser therapy that is based on photothermolysis has been a widely used treatment for various skin diseases such as skin cancers and port-wine stains. It offers several benefits such as non-invasiveness and selective treatment. However, the use of light, e.g., laser, for safe and effective photothermolysis becomes challenging due to the limited penetration of light into skin tissue as well as the presence of melanin, which absorbs this light. To solve the current issues, we propose an optical microneedle–lens array (OMLA) coated with gold in this work to directly deliver light to targeted skin layers without being absorbed by surrounding tissues as well as melanin, which results in the improvement of the efficiency of photothermal therapy. We developed a novel fabrication method, frame-guided micromolding, to prepare the OMLA by assembling two negative molds with simultaneous alignment. In addition, evaluations of the optical and heat transfer characteristics of the OMLA were performed. We expect our developed OMLA to play a crucial role in realizing more effective laser therapy by allowing the precise delivery of photons to the target area. [ABSTRACT FROM AUTHOR]

Gold coatings are the most widely used protective layer for resisting surface oxidization and corrosion in various complex environments. However, the extremely low hardness, inferior load‐bearing capacity, and lack of an effective strategy for evaluating the elastic‐plastic behavior of gold coatings have greatly limited their further application. The main aim of this work is to investigate the effect of Ni doping on the microstructure, mechanical properties, and electrical contact stability of a coating based on an experimental method and finite element simulation. The strain‐hardening exponent model of the coating is established by employing a reverse analysis method based on the nanoindentation experiment until the reverse and forward loading curves are consistent, thereby determining the yield strength. The results indicate that Ni doping is conducive to enhancing the mechanical properties under the premise of ensuring low contact resistance. The hardness (3.3–4.2 GPa) and yield strength (524.3–689.8 MPa) of the Au1−xNix composite coating with a Ni content of 4 at–8 at% is more than twice as high as that of pure Au. The electrical contacts deposited by the Au1−xNix coatings maintain a low contact resistance range (1.12–3.29 mΩ) at a contact force of 10 gf. [ABSTRACT FROM AUTHOR]

Background: This study investigates the efficacy of sonodynamic and low-dose radiation with methylene blue and gold nanoparticles coated with apigenin sonosensitizer on breast cancer cells. Method and Materials: HR-TEM, UV-visible, zeta -potential, FTIR, and DLS were used to confirm the synthesized gold nanoparticles coated with apigenin. The concentration of gold nanoparticles coated with apigenin and methylene blue was calculated, and then ultrasound and 2 Gy x-rays were used to irradiate them. Results: The results showed that sonodynamic therapy in combination with radiation at a concentration of 8 µg/ml nanoparticles and 0.4 µmol methylene blue had a significant effect on cell death (0.26± 0.02). Conclusion: This study highlights the potential of sonodynamic therapy as a non-ionizing and non-invasive treatment, as well as the possibility of eliminating the side effects of cancer treatment by using green nanoparticles rather than chemical sensitizers. [ABSTRACT FROM AUTHOR]

Methotrexate (MTX) has poor water solubility and low bioavailability, and cancer cells can become resistant to it, which limits its safe delivery to tumor sites and reduces its clinical efficacy. Herein, we developed novel redox-responsive hybrid nanoparticles (NPs) from hyaluronic acid (HA) and 3-mercaptopropionic acid (MPA)-coated gold NPs (gold@MPA NPs), which were further conjugated with folic acid (FA). The design of FA-HA-ss-gold NPs aimed at enhancing cellular uptake specifically in cancer cells using an active FA/HA dual targeting strategy for enhanced tumor eradication. MTX was successfully encapsulated into FA-HA-ss-gold NPs, with drug encapsulation efficiency (EE) as high as >98.7%. The physicochemical properties of the NPs were investigated in terms of size, surface charges, wavelength reflectance, and chemical bonds. MTX was released in a sustained manner in glutathione (GSH). The cellular uptake experiments showed effective uptake of FA-HA-ss-gold over HA-ss-gold NPs in the deep tumor. Moreover, the release studies provided strong evidence that FA-HA-ss-gold NPs serve as GSH-responsive carriers. In vitro, anti-tumor activity tests showed that FA-HA-ss-gold/MTX NPs exhibited significantly higher cytotoxic activity against both human cervical cancer (HeLa) cells and breast cancer (BT-20) cells compared to gold only and HA-ss-gold/MTX NPs while being safe for human embryonic kidney (HEK-293) cells. Therefore, this present study suggests that FA-HA-ss-gold NPs are promising active targeting hybrid nanocarriers that are stable, controllable, biocompatible, biodegradable, and with enhanced cancer cell targetability for the safe delivery of hydrophobic anticancer drugs. [ABSTRACT FROM AUTHOR]

Interfering with the aggregation of the protein alpha-synuclein (aSyn) has been a topic of research for > 25 years, as this protein is found in pathognomonic protein aggregates in the brain of patients with Parkinson's disease and related synucleinopathies. This study aimed to characterize the adsorption of aSyn and the inhibition of aSyn fibril formation by nanocellulose (NC) and NC coated with gold atoms (NCCGAs) using by both in silico and laboratory approaches. First, using the HDOCK server and Ascalaph designer software we assessed the possible molecular interaction of partial aSyn (36–55) and full length aSyn (1–140) when exposed to NC and NCCGAs. We then used acid hydrolysis to synthesize NC and then it reacted with HAuCl4 to generate NCCGAs. The adsorption of aSyn by NC and NCCGAs was analyzed at 280 nm and the inhibition of aSyn fibril formation was assessed using Thioflavin T. By comparing the docking results, we found that NCCGAs have more and better adsorption to partial/full length aSyn than NC. Also, molecular dynamics simulations showed that adsorbed partial/full length aSyn display stable interactions and that this increases over time. Experimentally, the adsorption of aSyn and the inhibition of aSyn fibril formation were observed upon exposure to NC or NCCGAs. Although both NC and NCCGAs adsorbed aSyn, NCCGAs had a higher capability (P > 0.05). The same pattern was observed for the inhibition of aSyn fibril formation. [ABSTRACT FROM AUTHOR]

A surface acoustic wave (SAW) resonator chip setup is presented that eliminates interfering signal responses caused by changes in the electrical environment of the surrounding media. When using a two-port resonator, applying electrically shielding layers between the interdigital transducers (IDTs) can be challenging due to the limited dimensions. Therefore, a layered setup consisting of an insulating polymer layer and a conductive gold layer was preferred. The SAW resonators were provided with polycarbonate housings, resulting in SAW resonator chips. This setup enables easy application of a wide range of coatings to the active part of the resonator surface, while ensuring subsequent electrical and fluidic integration of the resonator chips into a microfluidic array for measurements. The signal responses of uncoated SAW resonators and those with polymer coatings with and without a gold layer were tested with aqueous potassium chloride (KCl) solutions up to 3 mol/L, corresponding to conductivities up to 308 mS/cm. The use of a polymer coating at the thickness of the first Love mode resonance and a conductive gold layer completely reduced the electrical impact on the SAW resonator signal response, making small signals resulting from changes in viscosity and density of the KCl solutions visible. [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT) has been widely used in the treatment of tumors, but its efficacy is greatly limited by the inability of precise drug delivery and the increase of heat shock proteins (HSPs) caused by high temperature. This article describes a therapeutic strategy to enhance PTT with starvation therapy in conjunction with ferroptosis mechanism. A nanoparticle platform ZIF-8@GA was constructed by wrapping together glucose oxidase (GOX) and gold nanospheres (AuNPs) loaded with dihydroartemisinin (DHA) with zeolitic imidazolate framework-8 (ZIF-8). This platform can take advantage of the micro-environment of osteosarcoma (OS) cells, featuring low pH and high reactive oxygen species (ROS), for precision drug delivery. GOX can effectively catalyze glucose to produce gluconic acid and H2O2, and DHA can also induce ROS production in OS cells. ROS produced by GOX and DHA can further generate lipid peroxidation (LPO) and lead to ferroptosis of OS cells. At the same time, ROS and LPO produced can inhibit the expression of HSPs, thereby increasing the therapeutic effect of PTT. In vitro experiments show that the nanoparticles are pH and ROS responsive. 1 µg/mL GOX combined with 0.2 µg/mL DHA promotes ferroptosis of OS cells, and increases the killing effect of near-infrared (NIR) on OS cells. Further in vivo experiments showed that the nano drug-delivery platform combined with PTT can effectively inhibit the growth of OS cells. Meanwhile, this study provides a new idea for the treatment of OS with biomaterials combined with various treatment methods. [ABSTRACT FROM AUTHOR]

The possibility of using C60F48 fluorofullerene molecules as sources of fluorine in reactions involving Au(111) has been demonstrated. Ultrahigh-vacuum scanning tunneling microscopy and X-ray photoelectron spectroscopy studies have shown that C60F48 molecules lose some fluorine atoms with time, forming molecules with the stoichiometric composition close to C60F36 fluorofullerene, which is confirmed by X-ray photoelectron spectroscopy data. The interaction of fluorine with the Au(111) surface occurs only under islands formed by fluorofullerene molecules losing some fluorine atoms. It has been shown that a С60F18 molecule does not react with the Au(111) surface. At the submonolayer coating of the gold surface with С60F18 fluorofullerene, the "herringbone" () reconstruction characteristic of the clean Au(111) surface remains unchanged both in the region free of formed fluorofullerene islands and under them, and С60F18 molecules keep their initial configuration in time. [ABSTRACT FROM AUTHOR]

Ultrasensitive and rapid detection of single extracellular vesicles (EV) in complex biological samples requires a biosensor that possesses remarkable specificity, cost‐effectiveness, and ease of use; however, this remains a big challenge owing to the small size and high heterogeneity of EV in samples. Although reported biosensors can detect biomarkers in complex biological samples, tedious preprocessing procedures, low sensitivity, and expensive and complicated production hinder their use in early‐stage cancer diagnostics. To address these issues, an optical microfiber modified with WS2‐supported gold nanobipyramid (Au NBPs) nanointerfaces for the ultrasensitive assay of prostate cancer (PC) exosomes is proposed. Owing to the strong localized surface plasmon resonance (LSPR) hotspots of the Au NBPs coupled with the WS2 nanointerface, the sensor could ultrasensitively detect exosomes with an ultralow limit of detection (LODs) of 23.5 particles mL−1 in phosphate‐buffered saline (PBS) solution and 570.6 particles mL−1 in 10% serum. The LOD of 23.5 particles mL−1 is two orders of magnitude lower than those reported for other cutting‐edge techniques. Based on this sensing scheme, the sensor can distinguish PC serum from healthy serum, and successfully diagnose patients' whole blood by capturing and sizing a single bioparticle. This work presents a novel method for analyzing whole blood with ultrahigh sensitivity. [ABSTRACT FROM AUTHOR]

Nanoparticles, especially gold nanoparticles (Au NPs) have gained increasing interest in biomedical applications. Used for disease prevention, diagnosis and therapies, its significant advantages in therapeutic efficacy and safety have been the main target of interest. Its application in immune system prevention, stability in physiological environments and cell membranes, low toxicity and optimal bioperformances are critical to the success of engineered nanomaterials. Its unique optical properties are great attractors. Recently, several physical and chemical methods for coating these NPs have been widely used. Biomolecules such as DNA, RNA, peptides, antibodies, proteins, carbohydrates and biopolymers, among others, have been widely used in coatings of Au NPs for various biomedical applications, thus increasing their biocompatibility while maintaining their biological functions. This review mainly presents a general and representative view of the different types of coatings and Au NP functionalization using various biomolecules, strategies and functionalization mechanisms. [ABSTRACT FROM AUTHOR]

In this work, we investigate a synthesis method for novel systems that involve the use of gold nanotriangles arrays (AuNTs) coated with poly(N-isopropylacrylamide) (pNIPAM) brushes, designed as smart platforms for the reversible confinement of bio-particles. Initially, we employed cost-effective nanosphere lithography to fabricate gold nanotriangles arrays. Next, polymer initiator groups were attached to the AuNTs surface through a spontaneous reduction approach, enabling exclusive functionalization of pNIPAM on the gold surface. Finally, we utilized surface-initiated atom transfer radical polymerization to graft pNIPAM brushes onto the gold surface. We systematically investigated the polymer initiator groups' grafting time and the polymerization time to control the thickness of the grafted pNIPAM brushes. Subsequently, we characterized the thermoresponsive properties of these hybrid structures using Atomic Force Microscopy (AFM) measurements, evaluating their ability to undergo on/off adsorption and desorption of polystyrene (PS) beads on their surface. Indeed, the combination of the thermosensitive pNIPAM polymer with AuNTs arrays results in the development of a precisely regulated two-dimensional active device which exhibits tunable properties with external temperature changes, making it a versatile platform suitable for a wide range of applications. [ABSTRACT FROM AUTHOR]

The effect of enhancement the hydrophobic properties of the ensemble of micro- and nanostructures ZnO as a result of coating with gold was discovered. For the first time, it has been shown that coating the ensemble with a micro- and nanoparticle ZnO layer of gold leads to a sharp increase in the wetting edge angle from 145° to 168° (water drop volume 5 mm3) and a decrease in the hydrophobicity/hydrophilicity transition time under ultraviolet irradiation. [ABSTRACT FROM AUTHOR]

An electrical connector is an important component for achieving the interconnection of electric equipment. However, the degradation of contacting parts within the electrical connector under repetitive mechanical insertion and extraction operations causes a decrease in the contact reliability level, resulting in considerable safety hazards. The coating quality, determining the degree of degradation of contact pairs, is considered a critical factor in fabricating more reliable and safer electrical connectors. In this paper, a gold and nickel coating is deposited onto the surface of a pin within an electrical connector using magnetron sputtering and is compared to an electroplated pin, and the effects of different processing techniques on the microstructure, mechanical properties, and wear behavior are systematically investigated. The measurement results indicate that the surface quality (uniformity and defect density) and mechanical properties (hardness and elastic modulus) of the gold/nickel coating based on magnetron sputtering are significantly better than those achieved using electroplating, showing excellent wear properties and electrical contact stability after repetitive insertion–extraction operations. This study is critical for the development of advanced coatings using a novel deposition technique. [ABSTRACT FROM AUTHOR]

Despite increasing interest in developing ultrasensitive widefield diamond magnetometry for various applications, achieving high temporal resolution and sensitivity simultaneously remains a key challenge. This is largely due to the transfer and processing of massive amounts of data from the frame‐based sensor to capture the widefield fluorescence intensity of spin defects in diamonds. In this study, a neuromorphic vision sensor to encode the changes of fluorescence intensity into spikes in the optically detected magnetic resonance (ODMR) measurements is adopted, closely resembling the operation of the human vision system, which leads to highly compressed data volume and reduced latency. It also results in a vast dynamic range, high temporal resolution, and exceptional signal‐to‐background ratio. After a thorough theoretical evaluation, the experiment with an off‐the‐shelf event camera demonstrated a 13× improvement in temporal resolution with comparable precision of detecting ODMR resonance frequencies compared with the state‐of‐the‐art highly specialized frame‐based approach. It is successfully deploy this technology in monitoring dynamically modulated laser heating of gold nanoparticles coated on a diamond surface, a recognizably difficult task using existing approaches. The current development provides new insights for high‐precision and low‐latency widefield quantum sensing, with possibilities for integration with emerging memory devices to realize more intelligent quantum sensors. [ABSTRACT FROM AUTHOR]

In this study, we developed physically adsorbed multi‐layer coatings using poly‐l‐lysine or poly(diallyldimethylammonium chloride) and gold nanoparticles, which were functionalized with bovine serum albumin for the chiral separation in electrochromatography. The approach involves sequentially depositing positively charged polymers and negatively charged citrate‐stabilized gold nanoparticles. By repeating this modification cycle, we created two‐ and four‐layer coatings, which were sequentially functionalized with albumin forming three‐ and five‐layer coatings that were finally applied for the separation of enantiomers of dl‐tryptophan. The formed coatings exhibit stability across a pH range of 2–10 and feature a dense, uniform surface, as confirmed by scanning electron microscope images. The number of layers impacted nanoparticle deposition density, with five‐layer coatings being denser than three‐layer ones. Five‐layer coatings enable baseline separation of dl‐tryptophan enantiomers, whereas three‐layer coatings require the presence of albumin in the background electrolyte for separation. Therefore, increasing the number of layers and gold nanoparticles density enhances albumin active center concentration on capillary walls, improving the separation of dl‐tryptophan enantiomers. The five‐layer coatings can be easily fabricated and possess good repeatability of analytes migration time. [ABSTRACT FROM AUTHOR]

Enhancement of proton energy has always been a key aspect addressed via laser-driven proton acceleration. As the target normal sheath acceleration protons are driven by the electric field produced at the target rear surface, the presence of a gold nanolayer on the surface of the target foil will enhance the energy of accelerated ion beams. In our study, we used a 30 fs laser pulse with a wavelength of 800 nm and a peak intensity of 3 × 10 20 W / cm 2 . The targets were 2 μm thick aluminum foils coated with a 10–20 nm layer of gold (Au). It was observed that the dynamics of proton acceleration from the foil target is a function of the position of the nanolayer (front or rear surface). 2D particle-in-cell simulation was also performed in support of the observed experimental results. [ABSTRACT FROM AUTHOR]

Coating gold nanostructures with a silica shell has been long considered for biomedical applications, including photoacoustic imaging. Recent experimental and modeling investigations reported contradicting results concerning the effect of coating on the photoacoustic response of gold nanostructures. Enhanced photoacoustic response is generally attributed to facilitated heat transfer at the gold/silica/water system. Here, we examine the photoacoustic response of gold core–silica shell nanoparticles immersed in water using a combination of the two temperature model and hydrodynamic phase field simulations. Here, of particular interest is the role of the interfacial coupling between the gold electrons and silica shell phonons. We demonstrate that as compared to uncoated nanoparticles, photoacoustic response is enhanced for very thin silica shells (5 nm) and short laser pulses, but for thicker coatings, the photoacoustic performance are generally deteriorated. We extend the study to the regime of nanocavitation and show that the generation of nanobubbles may also play a role in the enhanced acoustic response of core–shell nanoparticles. Our modeling effort may serve as guides for the optimization of the photoacoustic response of heterogeneous metal–dielectric nanoparticles. [ABSTRACT FROM AUTHOR]

Microrobots have emerged as a promising precision therapy approach that has been widely used in minimally invasive treatments, targeted drug delivery, and wound cleansing, and they also offer a potential new method for actively modulating gut microbiota. Here, a double-faced microrobot was designed to carry gut bacteria via covalently immobilizing the antibodies, and a corresponding integrated optical and magnetic dual-driving control system was also developed for precise control of the microrobot. The microrobot utilizes magnetic microsphere as its core, with one side coated in gold, which serves as the optical receptor surface and the interface for bacterial attachment. The specific gut bacterium, S. cerevisiae, was immobilized on the gold-coated side using the corresponding antibodies. The dual-driving control system enables the precise modulation of gut bacteria by synergistically manipulating the microrobots' movement via the optical field and magnetic field. The feasibility of independent and coordinated control using optical fields and magnetic fields was validated through experimental and numerical simulation approaches. This work introduces a novel method for the precise modulation of gut microbiota, providing a new avenue for disease treatments based on gut bacteria. [ABSTRACT FROM AUTHOR]

Purpose: The objective of the study was to qualitatively assess the micro-gap dimensions, connecting fitting surface profile, and bacterial leakage of cast high-gold-alloy UCLA abutments, with or without electrodeposited gold coatings attached to external hexagon implants. Materials and methods: Sixteen plastic UCLAs (PUCLAs) were cast with a high-gold-content alloy. Eight were electrolytically gold plated. Five machined cast-to-UCLA (GUCLA) control abutments were cast with the same alloy. All abutments were attached to external hexagon implants, giving 21 implant-abutment combinations (IACs). External perimeter micro-gaps measured with SEM under shadow eliminating silhouette illumination and 2000× magnification were averaged over three regions. The IACs were examined for E. coli leakage following an initial sterility test. Disassembled combinations were examined with SEM, and surface profiles were qualitatively assessed. Results: External micro-gap measurements did not reflect the variable connecting surface profiles, but average values < 5.0 μm were observed for all IACs measured under the shadow eliminating silhouette illumination for both cast and pre-machined external hexagon abutments with and without Au plating. E. coli transfer was observed in 3 of 5 PUCLA-plated and 2 of 5 PUCLA-non-plated IACs. No transfer occurred in the 3 GUCLA-non-plated or 2 GUCLA-plated control IACs. Abutment connecting surfaces, both Au-plated and not Au-plated, showed plastic deformation (smearing) in variable mosaic patterns across the micro-gap. Conclusions: Micro-gap dimensions < 5μm were obtained with both the high noble metal cast and pre-machined control external hexagon abutments with and without Au electrodeposited on the abutment connecting surface. Regions of intimate contact due to plastic deformation (smearing) of these surfaces were observed. A continuous smeared region around the circumference of the surfaces can provide an effective barrier to the egress of E. coli bacteria from the internal regions of the implant under static loading. The sample size was insufficient to determine if the gold coating resulted in a superior bacterial barrier. [ABSTRACT FROM AUTHOR]

Silver nanowires (AgNWs) with a low diameter, high aspect ratio, stable suspension, and easy synthesis have recently attracted the optoelectronic industry as a low-cost alternative to indium tin oxide transparent conductive films. However, silver nanowires are not chemically stable, and their conductivity diminishes over time due to reactions with atmospheric components. This is a bottleneck for their wide industrial applications. In this study, we aim to address this issue by synthesizing silver nanowires with an average diameter of approximately 65 nm and a length of approximately 13 µm. The prepared Ag nanowires are then applied to fabricate transparent, flexible, and chemically stable conductive films. The fabrication includes spraying of silver nanowires suspension on a glass substrate followed by Dr. blade coating of polystyrene (PS) solution and delamination of the PS-AgNWs film. The resulting film exhibits an optimum sheet resistance of 24 Ω/□ and transmittance of 84%. To further enhance the stability of the transparent conductive film, the facial and scalable double pulse electrodeposition method is used for coating of gold on the exposed surface of the AgNWs embedded in PS. The final transparent film with gold coating demonstrates a remarkable stability under harsh conditions including long exposure to UV light and nitric acid solution. After 100 min of UV/Ozone treatment, the increase in sheet resistance of the optimal PS-AgNW@Au sample is 15.6 times lower than the samples without gold coating. In addition, the change in sheet resistance after 2000 bending cycles in the optimal PS-AgNW@Au electrode is measured and it showed an increase of only 22% of its initial sheet resistance indicating its good flexibility. The proposed electrode performs an excellent chemical stability, good conductivity, transparency, and flexibility that makes it a potential candidate for various optoelectronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Palladium-based nanocatalysts play an important role in catalyzing the cathode oxygen reduction reaction (ORR) for fuel cells working under alkaline conditions, but the performance still needs to be improved to meet the requirements for large-scale applications. Herein, Au@Pd core–shell nanowires have been developed by coating Pd atomic layers on ultrafine gold nanowires and display outstanding electrocatalytic performance towards alkaline ORR. It is found that Pd overlayers with atomic thickness can be coated on 3 nm Au nanowires under CO atmosphere and completely cover the surfaces. The obtained ultrafine Au@Pd nanowires exhibit an electrochemical active area (ECSA) of 68.5 m2/g and a mass activity of 0.91 A/mg (at 0.9 V vs. RHE), which is around 3.1 and 15.2 times higher than that of commercial Pd/C. The activity loss of the ultrafine Au@Pd nanowire after 10,000 cycles of accelerated degradation tests is only ∼20 %, demonstrating its much better stability compared to commercial Pd/C. Further characterizations combined with density functional theory (DFT) calculations demonstrate that the electronic interactions between Pd atomic layers and underlying Au can increase the electronic density of Pd and promote the efficient activation of oxygen, thus leading to the improved ORR performance. [ABSTRACT FROM AUTHOR]

Herein, we investigated the photoreduction of silver (Ag) ions on gold nanorods coated with mesoporous silica shell (AuNRs@mSiO2) induced by hot electrons generated in Au via localized surface plasmon resonance (LSPR) excitation. In addition, we investigated chemical interface damping (CID) using pyridine as the adsorbate in single Ag‐coated AuNRs@mSiO2. The Ag deposition caused a blue shift and linewidth broadening of the LSPR peak of the AuNRs@mSiO2. The subsequent chemisorption of pyridine on Ag‐coated AuNRs@mSiO2 resulted in a red shift and additional LSPR linewidth broadening. Finally, we demonstrated real‐time time‐dependent changes in LSPR peak wavelength and linewidth during the sequential processes of hot electron‐mediated Ag deposition and pyridine adsorption on a single AuNR@mSiO2 in a flow cell. Therefore, we provided a deep understanding of hot electron‐triggered Ag coating and CID induced by pyridine adsorption in single AuNRs@mSiO2 coated with Ag. [ABSTRACT FROM AUTHOR]

A method for technical evaluation of sealing agent used for rapid roll-to-roll gold electroplating in laboratory were established from the following aspects: properties of gold coating, efficiency of sealing, cost of sealing agent, and environmental friendliness. The test methods were described. The comprehensive performance of three sealing agents were quantitatively evaluated, providing a reference for plating plants to select excellent sealing agent for gold coatings. [ABSTRACT FROM AUTHOR]

Localized surface plasmon resonance (LSPRs) shown by gold nanorods (AuNRs) has several applications in photocatalysis, sensing, and biomedicine. The combination of AuNRs with Polydopamine (PDA) shells results in a strong photo‐thermal effect, making them appealing nanomaterials for biomedical applications. However, the precise roles and relative contributions of plasmonic effects in gold, and light‐to‐heat conversion in PDA are still debated. Herein, a hybrid nanoplatform made by an AuNR core surrounded by a polydopamine (PDA) shell is synthesized, and its photocatalytic behavior is studied. Synthesis is based on a seed‐mediated growth followed by the further self‐polymerization of dopamine hydrochloride (DA) on the surface of the AuNRs, and the effect of the thickness of the PDA shell on the plasmon response of the composite is the main examined parameter. Photocatalytic performance is tested toward Rhodamine 6G (Rh6G), with the nanocomposites achieving better performance than bare AuNRs and bare PDA nanoparticles. The degradation of 54% of Rh6G initial concentration is achieved within 60 min of irradiation with a catalyst concentration of 7.4 µg mL−1. Photodegradation kinetics, time‐resolved spectroscopy, and finite‐element‐method simulations of plasmons show that AuNRs plasmons, coupled with the low thermal conductivity of PDA, provide slow thermalization, while enhancing the charge carrier transfer. [ABSTRACT FROM AUTHOR]

In this work, gold nanoparticles (NPs) of 100 nm in size were added to the active layer of DSSC. The electrolyte is a gel polymer electrolyte (GPE) containing PEO, PhCh, TPAI, BMII, I2, DMF, EC, TBP, and GuSCN. The DSSCs have been characterized via J–V characteristics, IMVS, and IMPS measurements. On illumination at AM 1.5, the cell with 3 wt.% Au NP in the photoanode exhibits an η of 8.56% with Jscof 19.82 mA cm−2, Voc of 0.72 V and FF of 60%. The same cell also exhibited the lowest τtr of 7.32 ms and longest τrec of 115.33 ms. [ABSTRACT FROM AUTHOR]

Cyanide-based baths are generally used industrially to produce silver and gold coatings via electroplating. Baths containing ([Au(CN)2]−) and ([Ag(CN)2]−) are used for the deposition of gold and silver coatings, respectively. However, due to the severe toxicity, the technical personnel involved in work are at risk. Additionally, the disposal of cyanide-containing wastes poses a significant threat to the environment as they pollute various natural resources. The coatings produced from alkaline cyanide-based baths cause embrittlement of electronic circuit patterns. Due to these reasons, many cyanide-free baths have started to replace the existing cyanide-based baths. In the cyanide-free baths, the primary cyanide complexing agent is replaced with eco-friendly alternative compounds like sulphite, thiosulphate, thiourea, DMH, EDTA, and ionic liquids (ILs). This review article provides an overview of the various cyanide-free electroplating baths available for electroplating silver and gold that are either used for commercial practice or are developed for laboratory-scale use. [ABSTRACT FROM AUTHOR]

Copyright of South Architecture / Nanfang Jianzhu is the property of South Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Molecular thermal motion has been studied but yet never been utilized as an energy source. In this work, we demonstrate that the energy of liquid molecular thermal motion can be converted into electrical energy by a novel harvesting device, the molecular thermal motion harvester (MTMH). The MTMH was made by using two ZnO-based nano-arrays and one of which was gold coated to form a Schottky junction. The assembled electrodes were immersed in different liquid phase environments. The device was demonstrated to convert the molecule thermal energy of the liquid into a continuous and stable electric current. The output voltage and current can achieve 2.28 mV and 2.47 nA, respectively, and increase with the liquid temperatures. This strategy opens new insights into the development of mini- and micro-scale energy sources, and it can be expected the MTMH will have broad applications in the future. [ABSTRACT FROM AUTHOR]

The surface plasmon resonance of gold nanoparticles causes visible light absorption and scattering effects that may be used in optical coatings for eliminating blue light emission from display monitors, for blocking UV light, and for decorative applications. This study examines the achievement of functional properties provided by gold nanoparticles in a commercially established C60 fullerene-coated eyewear product. The gold nanoparticles used were sourced from recycling rapid lateral flow tests (LFIA), which use gold nanoparticles as test markers. After the gold's recovery, Ultrasonic Spray Pyrolysis (USP) with freeze-drying was used for the synthesis of new gold nanoparticles, to be used in optical coatings. The gold nanoparticles were examined with SEM, TEM, DLS, zeta potential, BET, and Vis-NIR for characterising their shapes and sizes, as is required for determination of the surface plasmon resonance effect. After applying the newly produced gold nanoparticles with fullerene C60 in a combined coating for eyewear lenses, the absorption and transmission of the lenses were determined for establishing changes in the coating's functionality. The results show that enhancing the fullerene C60 coating with gold nanoparticles improves light absorption and reflectance for blue and UV light further, which may be evaluated as beneficial for the eyewear user, as the reduction in eye strain is increased due to the coating. [ABSTRACT FROM AUTHOR]

This article, titled "Cover Picture and Issue Information," discusses a new system developed by Rüegg, Motes-Rodrigo, et al. that combines a robotic platform and a dummy to study the behavior of social insects, specifically the slender ant Leptothorax acervorum. The dummy, which is the size of an ant, provides tactile stimulation to the ants, and the robotic platform allows for precise control of the experiments. The authors believe that this system will help uncover the individual-level behavioral rules that govern social insect colonies and contribute to a better understanding of decentralized collective systems. The article includes a cover image illustrating the ant-size dummy and the robotic platform. [Extracted from the article]

The scattering problem for a dimer consisting of a carbon nanotube (CNT) coated with a thick gold layer everywhere except for a narrow central region is solved in the far-IR range by numerical methods. The nanotube in such a dimer is a low-conductive channel that slows the flow of charges between the two parts of the highly conductive gold coating. Charge-transfer plasmon resonance arises at a frequency of 21 THz in the spectrum of the absorption cross section of a dimer with a length of 285 nm and a transverse size of 20 nm. The resonance width is determined by the electron relaxation time in the CNTs. The resonant frequency is shown to decrease and the absorption cross section at the resonant frequency, to increase with increases in the transverse and longitudinal dimensions of the dimer. The presence of contact resistance between the CNT and the gold layer leads to a shift of the resonant frequency to the low-frequency region and a decrease in the absorption peak intensity. The ability to vary the CNT conductivity by electrostatic doping makes it possible to use such dimers as building blocks for metamaterials with controlled resonant properties in the far-IR range. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Elektronik Industrie is the property of Hüthig GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical interface damping (CID) is a recently proposed plasmon decay channel in gold nanoparticles. However, thus far, a very limited number of studies have focused on controlling CID in single gold nanoparticles. Herein, we describe a new simple method for reversible tuning of CID in single gold nanorods coated with a mesoporous silica shell (AuNRs@mSiO2). We used 1-alkanethiols with two different carbon chain lengths (1-butanethiol and 1-decanethiol) as adsorbates to induce CID. In addition, NaBH4 solution was used to remove the attached thiol from the AuNR surface. We confirmed the adsorption and removal of 1-alkanethiols on single AuNRs@mSiO2 and the corresponding changes in localized surface plasmon resonance (LSPR) peak wavelengths and linewidths. Furthermore, we investigated the effect of immersion time in NaBH4 solution on thiol removal from AuNRs@mSiO2. Therefore, the LSPR properties and CID can be controlled, thereby paving the way for in situ reversible tuning of CID by repeated adsorption and desorption of thiol molecules on single AuNRs@mSiO2. [ABSTRACT FROM AUTHOR]

One of the most important problems in the plasmonics of the terahertz (THz) range, which is actively developing now, is the efficient generation of surface plasmon polaritons (SPPs). The simplest and most promising technological technique of photon excitation of THz SPPs is through diffraction of radiation on the edge of the conducting surface of the sample (the end-fire coupling technique). In this paper, we experimentally evaluated the efficiency of the generation of monochromatic THz SPPs (λ0 = 141 μm) by this method with a sample in the form of a cylindrical segment, the convex surface of which has a gold layer coated by zinc sulfide (ZnS) with thickness d = 0–2 µm. Such configuration of the surface supporting the SPPs not only shields the detector from parasitic bulk waves arising during diffraction but also enables one to change the distribution of the SPP field in the air by varying the coating layer thickness d. On an uncoated gold surface, the SPP generation efficiency was η ≈ 20%. In the presence of a ZnS layer on the gold, the SPP generation efficiency gradually increased with d, reached the maximum (ηmax ≈ 60%) at d ≈ 1 μm, and then gradually decreased. Theoretical analysis showed that the efficiency of the SPP generation can be raised up to 80% due to the selection of an optimal SPP field profile via variation of the thickness of the dielectric layer on the metal surface, as well as with optimal incidence of the focused radiation on the edge of the sample. [ABSTRACT FROM AUTHOR]