Au Nanoparticles Research Articles

Metal-phenolic nanoparticles enhance low temperature photothermal therapy for bacterial biofilm in superficial infections.

Bacterial infections, especially induced by multidrug-resistant pathogens, have become a significant global health concern. In the infected tissues, biofilms not only serve as a source of nutrients but also act as protective barriers that impede antibiotic penetration. Herein, we developed tea polyphenols epigallocatechin gallate (EGCG) Au nanoparticles (E-Au NPs) through direct one-step self-assembly methods by EGCG chelating with Au ions to eradicate antibiotic-resistant bacteria methicillin-resistant Staphylococcus aureus (MRSA) and prevent the formation of biofilm under near-infrared (NIR) irradiation. The outstanding antibacterial effect involved in mild photothermal therapy, reactive oxygen species production, pathogenicity-related genes regulation, and quinoprotein formation that were specific to the polyphenol-based NPs. The excellent antibacterial and anti-inflammatory therapeutic efficacy of E-Au NPs was validated and topically applied in murine MRSA-infected skin wounds and keratitis model in vivo to kill bacteria, reduce the inflammation response and promote wound healing. Furthermore, the ophthalmic and systemic biosafety profiles were thoroughly evaluated while no significant side effects were revealed achieving a balance between high-efficiency antibacterial properties and biocompatibility. This study provides an effective therapeutic agent of metal-phenolic materials for superficial tissue infection with favorable prognosis and potential in clinical translation.

Remarkably Boosted High‐Temperature Electrostatic Energy Storage of Polyetherimide Film Induced by TiO2@Au@AlOx@Au Core‐shell Nanofibers

AbstractPolymer dielectrics have broad applications in advanced electronics and power systems. However, they suffer from low energy density and poor breakdown performance at high temperatures, limiting their applications in high‐temperature environments. Herein, TiO2@Au@AlOx@Au nanofibers with double coulomb blockade nanolayers are obtained via a physical sputtering strategy to improve the high‐temperature energy storage performance of polyetherimide composites. Experimental studies and finite elemenet phase‐field simulations demonstrate that the double‐layer coulomb blockade effect and micro‐capacitor effect of Au nanoparticles synergistically enhance the breakdown strength and dielectric permittivity of polyetherimide composite at high temperatures. Notably, the composite exhibits ultra‐high discharged energy densities of 11.33 and 9.70 J cm−3 at 150 and 200 °C, respectively, along with high charge–discharge efficiencies of 93.4% and 84%, which far exceed that of the polymer nanocomposites reported so far. Furthermore, the composite exhibits excellent charge–discharge cycling performance (>50000 cycles at 400 MV m−1) and high‐power density (1.16 MW cm−3) at 200 °C, making it an ideal candidate for high‐temperature capacitors. Hopefully, these nanofibers not only serve as excellent nanofillers for high‐temperature energy storage dielectric composites but also holds tremendous potential and inspirational significance for other applications such as electronics, biomedical fields, optics, and catalysis.

Realizing Bidirectional Photocurrent in Monolithic Dual‐Mode Device for Neuromorphic Vision and Logically‐Encrypted Transmission

AbstractDue to significant response contradictions, unidirectional carrier transmission of typical semiconductor p‐n junctions limits integrated sensors and artificial synapses in a monolithic device. In this work, a bipolar p‐n junction designed by employing the hydrogel/p‐GaN local contact interface with p‐GaN/(In,Ga)N heterojunction, demonstrating the bidirectional photocurrent and sensor/artificial synapse dual‐mode device successfully. After modifying Au nanoparticles, the negative (positive) photocurrent is increased by 900% (300%) under 365 nm (520 nm) light to achieve a more balanced bipolar carrier dynamic. Such a regulation of photocurrent is found to be attributed to the promotion of hydrogen evolution reaction (HER) at the hydrogel/Au/p‐GaN interface. Thus, the device achieves the ultrahigh paired‐pulse facilitation (PPF) index of 243% under self‐powered condition. Moreover, the implementation of plasticity from short‐term to long‐term demonstrates its adaptability in neural morphology visual recognition. Beyond independent working mode, the function of five classic logic gates is achieved under three‐terminal operation. Finally, an encrypted wireless communication system using dual‐channel light signals demonstrates the extensive application potential of the monolithic device. Therefore, this work presents a viable construction blueprint to meet the demands of next‐generation all‐in‐one optoelectronics for intricate application scenarios.

Engineering MXene Surface via Oxygen Functionalization and Au Nanoparticle Deposition for Enhanced Electrocatalytic Hydrogen Evolution Reaction.

MXene, a family of 2D transition metal carbides and nitrides, presents promising applications in electrocatalysis. Maximizing its large surface area is key to developing efficient non-noble-metal catalysts for the hydrogen evolution reaction (HER). In this study, oxygen-functionalized Ti3C2Tx MXene (Ti3C2Ox) is synthesized and deposited gold nanoparticles (Au NPs) onto it, forming a novel composite material, Au-Ti3C2Ox. By selectively removing other functional groups, mainly -O functional groups are retained on the surface, directing electron transfer from Au NPs to MXene due to electronic metal-support interaction (EMSI), thereby improving the catalytic activity of the MXene surface. Additionally, the interaction between Au NPs and -O functional groups further enhanced the overall catalytic activity, achieving an overpotential of 62 mV and a Tafel slope of 40.1 mV dec-1 at a current density of -10 mA cm-2 in 0.5 m H2SO4 solution. Density functional theory calculations and scanning electrochemical microscopy with ≤150 nm resolution confirmed the enhanced catalytic efficiency due to the specific interaction between Au NPs and Ti3C2Ox. This work provides a surface modification strategy to fully utilize the MXene surface and enhance the overall catalytic activity of MXene-based catalysts.

Probing the Effect of pH Value and Voltage on the Near‐Surface Proton Concentration at the Electrochemical Interface by In Situ Electrochemical Surface‐Enhanced Raman Spectroscopy (EC‐SERS)

ABSTRACTUnderstanding the variation of proton concentration near the surface of the electrochemical interface is of great significance for understanding the mechanism of electrochemical reactions. In this work, 4‐Mpy molecules that are protonated and deprotonated depending on the surrounding pH value adsorb on the Au nanoparticle film electrode with high SERS activity, and by virtue of the highly interfacial‐sensitive EC‐SERS technique, we systematically studied the effects of electrolyte pH value and external voltage on the protonation and deprotonation of 4‐Mpy at the interface between Au‐NP film electrode and phosphate buffer, to analyze the changes of near‐surface proton concentration at the electrochemical interface. It is found that the pH value of the electrolyte plays a decisive role in the protonation process of 4‐Mpy at the electrode interface at low reduction voltage (< −0.1 V). In acidic and neutral solution, 4‐Mpy exists mainly in protonated form on the electrode surface. However, in alkaline solutions, 4‐Mpy exists mainly on the electrode surface in the form of deprotonation. At high reduction voltage (≥ −0.1 V), the protonation and deprotonation of 4‐Mpy on the electrode surface are mainly determined by the adsorption structure of 4‐Mpy on the electrode surface. At the same time, we conducted a comparative study of 2‐Mpy and 4‐Mpy molecules and found that the adsorption modes were different depending on the position of the N atom. 2‐Mpy is inclined adsorbed on the surface of the Au‐NP film electrode, and 4‐Mpy is vertically adsorbed on the surface of the Au‐NP film electrode.

Biosynthesis of gold and silver nanoparticle using water hyacinth (Eichhornia crassipes) extract for photocatalytic degradation of organophosphate and organochlorine pesticide

The study aimed to assess the efficiency of synthesized gold (Au) and silver (Ag) nanoparticles in the degradation of organochlorine and organophosphate pesticides through photocatalysis. The synthesis of gold and silver nanoparticles was achieved using Eichhornia crassipes (water hyacinth extract). Photocatalytic degradation tests were conducted on organochlorine and organophosphate pesticides using gold and silver nanoparticles, with the absorbance of the samples measured by a UV spectrophotometer. The photocatalytic degradation rates of organochlorine and organophosphate were determined, with varied concentrations of the synthesized nanoparticles. The results showed high degradation rates at lower concentrations (10–20 ppm), with degradations of 51.789%, 47.954%, 47.983%, 44.088%, 41.565%, and 36.749% for 25/75, 50/50, and 75/25 Au nanoparticle ratios, respectively. The results also revealed that higher degradation rates were observed at longer reaction times (70–80 minutes), with percentage degradations of 44.344% and 49.987%, 41.754% and 45.937%, 36.773% and 40.458% for 25/75, 50/50, and 75/25 Au nanoparticle ratios, respectively. Lower degradation efficiencies were observed at shorter reaction times (10–20 minutes), with percentage degradations of 15.356% and 19.982%, 13.746% and 17.082%, and 10.976% and 15.167% for 25/75, 50/50, and 75/25 ratios, respectively. Additionally, the results showed high degradation rates at lower concentrations (10–20 ppm) for Ag nanoparticles, with percentage degradations ranging from 40.814% to 44.822% across AgNP ratios (25/75, 50/50, 75/25), indicating efficient degradation at lower concentrations. Conversely, at higher concentrations (60–80 ppm), the degradation efficiency was notably lower, with percentage degradations ranging from 7.004% to 13.539% across different AgNP ratios. In conclusion, Au nanoparticles exhibited higher photocatalytic efficiency than Ag nanoparticles, particularly in degrading organophosphate (Sniper) pesticides. It is recommended that these synthesized nanoparticles be considered as environmentally friendly and cost-effective options for pesticide degradation.

Simulation of blood flow in a tapered artery with ternary hybrid nanofluid and Jeffrey model

This research simulates flow of blood in a tapered peristaltic artery integrating ternary hybrid nanofluid using the Jeffrey fluid model. The simulation examines the effects of Au, Fe3O4, and Ag nanoparticles on the flow. The artery, modeled as a peristaltic channel, is subjected to nonlinear thermal radiation, magnetic forces, and heat source. The problem is formulated using non-linear Cartesian partial differential equations, which are then transformed into dimensionless form without approximations. Adomian Decomposition Method (ADM) is employed to solve these equations, revealing how normal and shear stress, normal and axial velocities, induced magnetic fields, and temperature profiles vary with changes in relevant parameters. Additionally, biological factors are considered to graph streamlines, providing a comprehensive analysis of the flow dynamics. Some notable results include that adding ternary nanoparticles increases the Nusselt number by 26.03% in Newtonian fluids and 158.69% in Jeffrey fluids, and increasing tapering parameters and wavenumber improves axial and normal velocities, heat transfer, and flow complexity.

(Fe, Co) oxide nanowires on gold nanoparticles modified MOF-derived carbon nanoflakes for high-efficiency sodium-ion batteries and supercapacitors across electrolytes

The three-dimensional conductive porous carbon nanosheets (CPCN) are from the bimetallic metal-organic framework (MOFs) consisting of organic ligating groups that incorporate zinc and cobalt ions deposited onto a flexible carbon cloth (CC). Utilizing a hydrothermal approach, iron-cobalt oxide (FCO) nanowires are intricately embedded onto CPCN modified with gold (Au), forming a flexible FCO/Au/CPCN@CC electrode. The electrochemical characteristics of electrodes are evaluated in 1 M Na2SO4, supercapacitor's storage capacity is tested at 4 V using 1 M NaPF6 electrolyte. Among its remarkable attributes are a peak energy density of 291.5 W h kg−1 achieved at a power density of 153.85 W kg−1, and even at the maximum power density of 1749.9 W kg−1, it maintains 144.78 W h kg−1. Undergoing 10,000 rounds of GCD, the equipment sustains a capacitance retention of 84.27 %. Moreover, the performance of the FCO/Au/CPCN@CC anode in sodium-ion batteries (SIBs) is assessed. At 0.1C, the discharge capacity reaches 958 mAh g−1, and there is almost no loss after the rate cycle. The Coulomb efficiency surpasses 98 % during 500 cycles at a large C-rate. The integration of Au nanoparticles onto the CPNC surface enhances the energy storage characteristic of the FCO/Au/CPCN@CC composite material in both battery and supercapacitor applications.

In-depth mechanistic insights into Au nanoparticles based polyurethane foams as a selective and efficient dispersive solid phase microextractor for textile dyes from water: performance and reusability study

ABSTRACT Herein, a simple, superhydrophobic, superoleeophilic and low cost microextractor Au nanparticles (Au NPs) based polyurethane (PUFs) solid platform (Au NPs/PUFs) has been developed as a promising sorbent for removal and recovery of Congo red (CR) textile dye from water bodies. The sorbent was characterised using UV-visible and SEM techniques. The procedure relied complete dye retention from the aqueous solution at pH 5.0–5.5 onto an Au NP/PUF extractor. Analytical assessments revealed that the Au NPs/PUFs combination significantly improves mass transfer of dye and enhances creation of active sites for CR retention. CR sorption by the sorbent fitted well with intra-particle diffusion and pseudo first-order kinetic models (R2 = 0.990). The enthalpy change, ΔH (37.8 kJ mol−1) indicates that dye extraction is endothermic whereas the entropy change, ΔS0 (116.6 J mol−1K−1), reveals a significant change in the entropy during dye uptake. The free energy change ΔG (3.12 kJ mol−1 at 298 K) of CR sorption indicated that the dye retention was not spontaneous at all temperatures. A twofold sorption mechanism involving absorption accompanying ‘solvent extraction’ and/or ‘weak ion exchange’, combined with surface adsorption of dye is proposed. Sorbent packed mini column demonstrated effective percent removal and recovery (101.8%) of CR from water samples using acetone or NaOH as an eluting agent. The study expands the utility of Au NPs/PUFs for reusability and spectrophotometric sensing of trace levels of CR in water. The key attention also includes integrating PUFs utility by improving the selectivity and sensing properties towards textile dyes.

An electrochemiluminescence sensor for ultrasensitive determination of tyrosine based on ceria nanomaterial as a novel luminophor

BackgroudRecently, optical nanomaterials have attracted much attention in the field of electrochemiluminescence (ECL). Nanostructured ceria possessed unique optical properties, and it's always used for constructing ECL sensor as catalyst for improving sensing performance, while the ECL property of ceria is rarely studied. In fact, it could be the potential candidate for applying in ECL sensors based on size and shape dependency optical property caused by the quantum scale effects. Therefore, new simple and efficient ceria nanomaterial used as luminophor for constructing the ECL sensor have aroused more research interest and motivation. (91 words). ResultsIn the work, three kinds of nanostructured ceria, ceria nano-cube (CeO2-NC), ceria nano-rods (CeO2-NR) and ceria nano-particle (CeO2-NP), have been prepared by hydrothermal method, and CeO2-NC with the less oxygen vacancy has the highest ECL signal. Moreover, how the shape affects the ECL property was investigated in detail, especially the oxygen vacancy on the surface of the ceria. The less of oxygen vacancy content of CeO2 nanomaterials is more favorable the ECL reaction. Furthermore, a novel ECL sensor was constructed based on reduced graphene oxide (rGO), Au nano-particle (AuNPs) and CeO2-NC for Tyrosine (Tyr) determination owing to the electron transform between the luminous of ceria and Tyr resulting in the cathodic ECL intensity quenched correspondingly, and it has possessed excellent sensing performance with a linear range of 0.005–20 nmol/L and the limit of detection (LOD) value of 1.7 fmol/L (141 words) Significance and noveltyThe proposed method demonstrated excellent selectivity and ultra-sensitivity toward Tyr, which had been used for the determination of Tyr in human serum successfully, possessing outstanding analytical performance. Therefore, nanostructured ceria is a new category of efficient and promising luminophore, which would open new avenues for the potential application in the field of ECL sensing for clinical diagnosis. (57 words).

Lights on the Synthesis of Surfactant-Free Colloidal Gold Nanoparticles in Alkaline Mixtures of Alcohols and Water.

Surfactant-free colloidal syntheses in aqueous media are attractive to develop nanomaterials relevant for various applications, e. g. catalysis or medicine. However, controlled green syntheses without surfactants of metal nanoparticles in aqueous media remain scarce. Here, room temperature syntheses of gold (Au) nanoparticles (NPs) that require only HAuCl4, alkaline water and an alcohol, i. e. relatively benign chemicals and mild reaction conditions, are developed. The findings of a comprehensive multi-parameters screening performed in small volumes (<3 mL) over 1000+ experiments pave the way to greener high throughput screenings of large parametric spaces and lead to scalable (100 mL) synthetic strategies. A rational selection of the alcohol is proposed. The influence of lights with defined wavelengths (222-690 nm) is investigated. It is found that lights with lower wavelengths favor the formation of smaller 5 nm NPs. Different kinetics and formation pathways are observed for different alcohols and for lights with different wavelengths. The sensitivity to various experimental parameters increases with the alcohol used in the order glycerol<ethylene glycol<ethanol<methanol. New strategies for a rational fine size control, and to some extend shape control, are identified. The results lead to more sustainable and reproducible surfactant-free colloidal syntheses of NPs.

A Facile Microwave-Promoted Formation of Highly Photoresponsive Au-Decorated TiO2 Nanorods for the Enhanced Photo-Degradation of Methylene Blue

The integration of noble metal nanoparticles (NPs) effectively modifies the electronic properties of semiconductor photocatalysts, leading to improved charge separation and enhanced photocatalytic performance. TiO2 nanorods decorated with Au NPs were successfully synthesized using a cost-effective, rapid microwave-assisted method in H2O2 and HF media for methylene blue (MB) degradation under visible light illumination. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 physisorption, and UV–vis spectroscopy were employed to characterize the structures, morphologies, compositions, and photoelectronic properties of the as-synthesized materials. The fusing of Au NPs effectively alters the electronic structure of TiO2, enhancing the charge separation efficiency and improved electrical conductivity. The HF treatment promotes the exposure of the highly reactive (001) and (101) crystalline facets. The improved photocatalytic activity of Au/TiO2, achieving 97% efficiency, is attributed to the surface plasmon resonance (SPR) effect of the Au NPs and the presence of oxygen vacancies. The photodegradation of MB using the TiO2/Au photocatalysts follows pseudo-first-order kinetics, highlighting the enhanced catalytic efficiency of the synthesized nanostructures. The exceptional properties of the binary Au/TiO2 photocatalysts, including the SPR effect, exposed crystallographic faces, and efficient charge carrier separation through a decrease in the recombination of electrons and holes, contribute to the photocatalytic degradation of MB.

Comparison of Au Nanoparticle/Poly(9-vinylcarbazole) Thin-Film Electrogeneration at 3 Distinct Liquid/Liquid Interfaces: Water/1,2-Dichloroethane, /α,α,α-Trifluorotoluene, Or/Ionic Liquid.

Metal nanoparticle (NP) incorporated conductive polymer films are attractive for their mechanical stability for biomedical applications and as heterogeneous electrocatalysis materials. Novel approaches to generate these materials with tunable properties are still being sought. Herein, the interface between two immiscible electrolyte solutions (ITIES) has been employed as a molecularly sharp and reproducible platform for simultaneous Au NP and poly(9-vinylcarbazole) generation. Three interfaces have been compared, including between water|1,2-dichloroethane (w|DCE), water|α,α,α-trifluorotoluene (w|TFT), and water|ionic liquid (w|IL). In this case the IL was P8888TB (tetraoctylphosphonium tetrakis(pentafluorophenyl)borate). 9-Vinylcarbazole (VC) can polymerize via two routes, either propagating through the vinyl substituent or the aryl rings. The former gives rise to a white semiconducting polymer with a wide bandgap, while the latter produces a green, conducting polymer. External potential control through voltammetric cycling was found to generate the film more rapidly favoring heterogeneous electron transfer with formation of the green poly(VC) variant at the ITIES. This was a free-standing film that could be easily removed from the interface. In the absence of external control, white polymer crystals formed within the oil phase spontaneously likely via AuCl4- w → o transfer followed by a homogeneous electron transfer reaction mechanism. Scanning electrochemical microscopy probe approach curve experiments were used to quantify the electroactivity of the film and are complemented by direct conductivity measurements.

Advanced plasmonic few-layered InSe nanosheet heterojunctions for enhanced photoelectrochemical water splitting

The selenide-based Van der Waals heterojunctions show great potential for the next generation of photoelectronic nanodevices. Herein, we construct a 2D photoanode nanocatalyst that consists of ZnSe nanocrystals with exposed active surfaces coupled with few-layered InSe nanosheets decorated by Au nanoparticles. The resultant ZnSe/AuNPs@InSe multi-heterojunction photoanode demonstrates an outstanding photocurrent density of 4.86 mAcm−2 under AM 1.5 G simulated sunlight (100 mWcm−2), which is 8 times greater than that of the pristine InSe photoanode (0.61 mAcm−2). Moreover, the lifetime of photogenerated charge carriers is extended by a factor of 3. This significant enhancement in photoelectrochemical water splitting in the near-infrared region is attributed to the surface plasmonic effect produced by the modification of Au NPs when bulk InSe is exfoliated into multi-layered flakes. The interfacial coupling effects on carrier transfer dynamics, as revealed by impedance spectroscopy assisted with the First-Principal calculations, show that this photoanode significantly minimizes the internal resistance, boosts the charge carrier separation efficiency, and promotes water oxidation.

Construction of electrochemical immunosensors based on Au@MXene and Au@CuS nanocomposites for sensitive detection of carcinoembryonic antigen

Cancer is currently one of the major causes of human mortality and has received widespread attention. In this paper, Au@CuS composite nanomaterial as a sandwich immunosensor tag for carcinoembryonic antigen (CEA) detection strategy was studied. Herein, Au@CuS composite nanomaterials were obtained by Au nanoparticles modified with CuS, which were combined with secondary antibody (Ab2) to construct an immunosensor that interacted with H2O2 to produce a current response. The anti-CEA primary antibody (Ab1) was fixed on the glassy carbon electrode (GCE) modified by Au@MXene. The completed electrochemical immunosensor was constructed with rapid detection and high sensitivity for CEA. Under optimal conditions, the linearity ranged from 0.01 pg/mL to 0.5 ng/mL, and the detection limit was 3.8 fg/mL. This tactic possesses good reproducibility, constancy and selectivity. At the same time, this strategy has latent practical value for the test of other tumor markers.

A systematic study on Au-PDA@Fe3O4 core-shell catalysts for enhanced catalytic reduction of 4-nitrophenol

The development of nanogold catalysts with high activity and high stability is of great significance for their industrial applications. In this paper, Au-PDA@Fe3O4 catalysts were prepared through the gold sol adsorption method. First, micron-sized magnetic Fe3O4 spheres were synthesized via a solvothermal method, serving as the core to endow the catalyst with excellent recyclability. Subsequently, a layer of polydopamine (PDA) shell was polymerized on the magnetic core surface. By controlling the timing of introducing the gold sol containing Au nanoparticles (NPs), the spatial position of Au NPs within the PDA layer was regulated, leading to a series of magnetic core-shell nano gold catalysts with varying spatial positions of Au. Using the 4-nitrophenol (4-NP) hydrogenation as the probe, the influence of Au spatial position, Au size, and other conditions on the catalytic performance was investigated. Results showed that, in the prepared Au-PDA@Fe3O4-16 catalyst, the Au NPs are encapsulated within the PDA shell and positioned close to the outer layer. This not only provides remarkable stability to the Au NPs but also maintains their proximity to the surface of the PDA shell, allowing easier access of the substrate 4-NP to the Au NPs and conferring good reactivity upon the catalyst. The strong electron metal-support interaction between PDA and Au enables PDA to effectively stabilize Au NPs. The prepared Au-PDA@Fe3O4-16 catalyst exhibits excellent stability, maintaining a high conversion rate of 91% even after 14 cycles of use. Our findings not only deepen the understanding of the catalytic mechanisms involved but also pave the path towards the creation of highly efficient and robust gold-based catalysts, facilitating their widespread utilization in industrial applications.

Construction of Au nanoparticles decorated on ZnFe2O4@ZnIn2S4 core-shell structure to enhance photocatalytic hydrogen production

Developing effective photocatalysts for water splitting is essential to generating H2 energy sources. Herein, a novel ZnFe2O4@ZnIn2S4/Au ternary composite (abbreviated as ZFO@ZIS/Au) was successfully designed and fabricated by loading Au nanoparticles on the ZFO@ZIS surfaces for effective photocatalytic H2 generation for the first time. Attributed to the synergistic effect of the traditional II-type heterojunction charge transfer and Au nanoparticles as co-catalysts, the ZFO@ZIS/Au heterojunction generated greater amounts of hydrogen under visible light irradiation. The ZFO-7%@ZIS/Au-2 catalyst displayed the highest H2 production rate of 1145.38 μmol∙g-1∙h-1, which was almost 3.87 times more than the ZIS value. Furthermore, several characterization techniques were performed to investigate the catalysts and evaluate the catalyst's photocatalytic activity when exposed to visible light. Lastly, a detailed discussion of the corresponding photocatalytic H2 production process of the as-prepared ZFO@ZIS/Au heterojunction was provided. The distinctive research might offer a potential approach for modifying zinc ferrate for photocatalytic hydrogen production.

Ultrasensitive detection of thiamethoxam by an aptasensor modified with reduced graphene oxide and Au nanoparticles

Ultrasensitive detection of thiamethoxam by an aptasensor modified with reduced graphene oxide and Au nanoparticles

Cryoprotective Effect of Zinc and Gold Nanoparticles During Cooling and Freeze-thawing on Marwari Stallion Sperm Parameters and Reactive Oxygen Species Production

BACKGROUND: Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. OBJECTIVE: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. MATERIALS AND METHODS: A total of 20 ejaculates from four Marwari stallions (five ejaculates from each) were collected. The gel free semen was extended with primary extender in equal volume and then divided in three equal groups, namely control (C), zinc (ZnO) and gold (Au), and centrifuged to obtain a final concentration of 100-150 x10 6 mL -1 and then cryopreserved. Cooled and post-thaw semen evaluations were conducted for various seminal characteristics, viz. progressive sperm motility, sperm plasma membrane integrity, sperm viability, acrosome integrity and mitochondrial membrane potential. RESULTS: Cooled semen (4ºC for 2 h) evaluation revealed nonsignificant differences among the groups (C, ZnO and Au) for all the semen quality parameters. However, at the post-thaw stage, progressive sperm motility, sperm plasma membrane integrity, acrosome integrity and oxidative parameters were significantly (P≤ 0.01) higher in the ZnO group than Au and C. CONCLUSION: The addition of ZnO nanoparticles improves the post thaw quality of stallion spermatozoa by reducing the oxidative stress, but Au nanoparticles had no effect on cooled as well as post-thaw semen quality.

Insight into interfacial dynamics of photogenerated carriers in Cs3Bi2I9/Au heterostructure nanocomposites for high-sensitivity broadband photodetection with negative photoconductivity

The negative photoconductivity (NPC) effect is becoming an increasingly significant factor in the development of next-generation optoelectronics. However, research in the field of NPC-dominated optoelectronics remains in its infancy and frequently encounters challenges related to fabrication complexity, slow photoresponse speed, instability, and a limited spectral response range. Herein, a Cs3Bi2I9/Au heterostructure nanocomposite was prepared via a simple self-assembly process utilizing electrostatic interactions with Au nanoparticles (NPs) and lead-free Cs3Bi2I9 nanoplates. The Cs3Bi2I9/Au nanocomposite-based photodetectors (PDs) demonstrate a broadband photoresponse (405–1550 nm), enhanced rise/fall times (27.2/40.0 µs), and reduced noise density (4.7 × 10−13 A/Hz1/2 at 1 Hz). In contrast to the positive photoconductivity (PPC) effect observed in colloidally synthesized Cs3Bi2I9 nanoplate-based PDs, the NPC can be attributed to the decrease in photocurrent under light illumination during the processes of recombination and trapping of photogenerated carriers induced by the incorporation of Au NPs. These findings are expected to provide valuable insights into achieving high-performance NPC-dominated PDs by regulating the dynamics of photogenerated carriers in perovskite heterostructures.