Au-Pt Bimetallic Nanoparticles Research Articles

Electrochemical and colorimetric dual-signal detection of Staphylococcus aureus enterotoxin B based on AuPt bimetallic nanoparticles loaded Fe-N-C single atom nanocomposite

Sensitive detection of Staphylococcus aureus enterotoxin B (SEB) is of importance for preventing food poisoning from threatening human health. In this work, an electrochemical and colorimetric dual-signal detection assay of SEB was developed. The probe (Ab2/AuPt@Fe-N-C) was bound to SEB captured by Ab1, where the Ab2/AuPt@Fe-N-C triggered methylene blue degradation and resulted in the decrease of electrochemical signal. Furthermore, the probe catalyzed the oxidation of 3,3’,5,5’-tetramethyl biphenyl to generate a colorimetric absorbance at 652 nm. Once the target was captured and formed a sandwich-like complex, the color changed from colorless to blue. SEB detection by colorimetric and electrochemical methods showed a linear relationship in the concentration ranges of 0.000 2–10.000 0 and 0.000 5–10.000 0 ng/mL, with limits of detection of 0.066 7 and 0.167 0 pg/mL, respectively. The dual-signal biosensor was successfully used to detect SEB in milk and water samples, which has great potential in toxin detection in food and the environment.

Bimetallic PtAu-Decorated SnO2 Nanospheres Exhibiting Enhanced Gas Sensitivity for Ppb-Level Acetone Detection.

Acetone is a biomarker found in the expired air of patients suffering from diabetes. Therefore, early and accurate detection of its concentration in the breath of such patients is extremely important. We prepared Tin(IV) oxide (SnO2) nanospheres via hydrothermal treatment and then decorated them with bimetallic PtAu nanoparticles (NPs) employing the approach of in situ reduction. The topology, elemental composition, as well as crystal structure of the prepared materials were studied via field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The findings revealed that bimetallic PtAu-decorated SnO2 nanospheres (PtAu/SnO2) were effectively synthesized as well as PtAu NPs evenly deposited onto the surface of the SnO2 nanospheres. Pure SnO2 nanospheres and PtAu/SnO2 sensors were prepared, and their acetone gas sensitivity was explored. The findings demonstrated that in comparison to pristine SnO2 nanosphere sensors, the sensors based on PtAu/SnO2 displayed superior sensitivity to acetone of 0.166-100 ppm at 300 °C, providing a low theoretical limit of detection equal to 158 ppm. Moreover, the PtAu/SnO2 sensors showed excellent gas response (Ra/Rg = 492.3 to 100 ppm), along with fast response and recovery (14 s/13 s to 10 ppm), good linearity of correlation, excellent repeatability, long-term stability, and satisfactory selectivity at 300 °C. This improved gas sensitivity was because of the electron sensitization of the Pt NPs, the chemical sensitization of the Au NPs, as well as the synergistic effects of bimetallic PtAu. The PtAu/SnO2 sensors have considerable potential for the early diagnosis and screening of diabetes.

Anchoring bimetallic PtAu nanoparticles on hierarchical zeolite as efficient electrocatalyst for the enhancement of ethanol electrooxidation

Zeolite materials as nanoreactor are promising candidates as catalysts for the oxidation of alcohol fuels. In the present work, the hierarchical zeolite was prepared via a hydrothermal technique. Then, the bimetallic Pt-Au-zeolite composite as electrocatalysts were synthesized by co-precipitation route. The surface morphology, composition and structure of the resulting composite were investigated by FE-SEM, EDS, XRD, XPS, BET&BJH and FT-IR. The catalytic performance of the composite has been examined in ethanol electrooxidation reactions under alkaline media. Pt-Au-zeolite exhibits superior selectivity for the electrooxidation of the ethanol, outperforming both conventional Au and Pt nanoparticles supported on zeolite crystals catalyst. The peak electrooxidation current of ethanol with Pt-Au-zeolite catalyst is 3.63 times that of Pt-zeolite with a scan rate of 50 mVs−1, which is due to the synergistic effect of Au and Pt in zeolite framework. It could be attributed to the incorporation of Au and Pt into zeolite framework, which was beneficial to the charge transferring the surface of Pt-Au-zeolite electrocatalyst and facilitated the ethanol oxidation. Besides, the significant electrochemical activity can be due to the production of OH–, which leads to the species present on the surface of the electrocatalysts during the activation process that controlled by the zeolite framework.

Fabricating a rapid and low-cost electrochemical biosensor with imprints of glycated albumin molecules to detect diabetes using bimetallic Au-Pt nanoparticles on μSPE

Diabetes is a primary factor that is accountable for health problems and results in millions of deaths. 4 million deaths approximately occurred due to diabetes every year and about 170 million people are suffering universally. For diabetes, no treatment is present that promises to cure this condition. Only blood glucose monitoring is recommended for diabetics. Regular and close monitoring of glucose levels can help to avoid further serious problems. Determining the level of glucose in the blood is an important requirement. This is done by monitoring the levels of glycated hemoglobin (HbA1c), which is a biomarker for glucose. But HbA1c monitoring is unreliable in the presence of certain medical conditions. In such cases another biomarker glycated albumin (GA) is used for glucose monitoring as it remains unaffected by such conditions. As a result, a bimetallic nanomaterial-based sensitive platform was created. This research focuses on the development of a biosensor that utilizes micro-screen printed electrodes (μSPE). The platform was designed to measure the level of GA and demonstrated the synergistic effects of bi-metallic gold-platinum (Au-Pt) nanomaterial. Additionally, the electrochemical response of mono-metallic and bi-metallic nanoparticles was investigated in order to detect glycated albumin, a diabetes biomarker. The biosensor constructed using bimetallic nanoparticles exhibits a broad range of concentrations, lower limit of detection, heightened sensitivity, and selectivity.

The development of electrochemical DNA biosensor based on poly-l-methionine and bimetallic AuPt nanoparticles coating: Picomolar detection of Imatinib and Erlotinib

We report on the preparation of a new and simple electrochemical DNA biosensor based on DNA/AuPt/p-L-Met coating on a screen-printed carbon electrode (SPE) and its use in the determination of the cancer therapy agents, Imatinib (IMA) and Erlotinib (ERL). Poly-l-methionine (p-L-Met), gold, and platinum nanoparticles (AuPt) were successfully coated by one-step electrodeposition onto the SPE from a solution containing L-Met, HAuCl4, and H2PtCl6. The immobilization of DNA was achieved by drop-casting on the surface of the modified electrode. Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive X-ray Spectroscopy (EDX), and Atomic Force Microscopy (AFM) were used to investigate the morphology, the structure, and the electrochemical performance of the sensor. Experimental factors influencing the coating and DNA immobilization processes were optimized. The peak currents originating from guanine (G) and adenine (A) oxidation of ds-DNA were used as signals to quantify IMA and ERL in the concentration range 2.33–80 nM and 0.032–1.0 nM with the LODs of 0.18 nM and 0.009 nM, respectively. The biosensor developed was suitable for determining IMA and ERL in human serum and pharmaceutical samples.

A highly sensitive MXene/AuPt/AChE-based electrochemical platform for the detection of chlorpyrifos

The MXene/AuPt nanocomposite was successfully synthesized through the reduction process, which possessed good biocompatibility and electron transfer capability. On the basis of the excellent performance of MXene/AuPt and the enzyme inhibition, an ultrasensitive and high-performance acetylcholinesterase (AChE)-based electrochemical biosensor was prepared for the detection of chlorpyrifos. The prepared biosensor combined the unique electrocatalytic property and synergistic effect of MXene nanosheets and AuPt bimetallic nanoparticles, which not only promoted the electron transfer capability, but also increased the electroactive surface area for the immobilization of AChE. The electrochemical performance was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. This biosensor exhibited good affinity towards AChE with a corresponding apparent Michaelis constant (Km) of 1.27 mM. Under optimal conditions, the electrochemical biosensing platform presented a good linear relationship in the range of 10−8−10−3 mg mL−1 and a low limit of detection of 1.55 pg mL−1. Furthermore, the as-prepared electrochemical biosensor exhibited high sensitivity, acceptable repeatability, and excellent stability, which implied the great potential for the detection of organophosphorus pesticides.

Au-Pt bimetallic nanoparticles anchored on conducting polymer: An effective electrocatalyst for direct electrooxidation of sodium borohydride in alkaline solution

This work proposes Au-Pt nanoparticles decorated poly(p-aminophenol) (PAP) film on a glassy carbon electrode for direct electrochemical oxidation of sodium borohydride. The Au-Pt bimetallic surfaces were prepared with two electrodeposition procedures which are the simultaneous electro-deposition (1-Au-Pt/PAP/GCE) and the successive electro-deposition (2-Au-Pt/PAP/GCE) procedures. The catalysts were used for the investigation of borohydride electrochemical oxidation and compared catalytic activities by CV, RDEs and chronoamperometric techniques. AFM, SEM, XPS, XRD and CV were used to identify of the structural and morphological properties of the developed modified surfaces. The results of electrochemical measurements indicated that simultaneous electro-deposition of Au-Pt to the polymer structure significantly shifted negative oxidation potential and increases the current density of borohydride electrochemical oxidation.The exchange electron number of 1-Au-Pt/PAP/GC and 2-Au-Pt/PAP/GC electrodes were calculated as 7.8 and 6.7, respectively. This approves the strong tendency of the 1-Au-Pt/PAP catalyst toward effective direct electrochemical oxidation of NaBH4 in an alkaline medium.

AuPt bimetal‐codecorated ZnO nanowire‐based hydrogen sensors for detecting low concentration hydrogen gas with high response and selectivity

AbstractZnO nanowires decorated with bimetallic AuPt nanoparticles were synthesized using the vapor–liquid–solid method, followed by sputtering and thermal annealing, to fabricate highly sensitive and selective sensors for detecting ppb scale hydrogen gas. The proposed sensor demonstrated a clear pattern enough to recognize, even for 100 ppb hydrogen gas. The sensing responses of the pristine and AuPt bimetal‐codecorated ZnO nanowire‐based sensors were 1.09 and 7.3 for 100 ppb hydrogen gas, respectively. The sensing response of the proposed sensor is seven times as the decoration of AuPt nanoparticles. Furthermore, the proposed sensor exhibited excellent sensing selectivity for various interfering gases including ethanol, acetone, toluene, CO, and H2S. The proposed sensor shows excellent sensing performance because of synergistic effect of decorated AuPt, which play the role of catalysts. Therefore, hydrogen sensors showing superior sensing performance can be fabricated using this nanomaterial, and its advanced sensing performances are analyzed in this study.

Bimetallic AuPt alloy nanoparticles decorated on ZnO nanowires towards efficient and selective H2S gas sensing

The development of high-performance H2S sensor is imperative for monitoring H2S in the living environment. Metal oxide semiconductors (MOSs) have been regarded as the strongest candidates for H2S detection due to their high sensitivity, miniaturization, and good durability. However, a single MOS-based gas sensor is unable to selectively detect gases, which limits its practical application. Functionalization of noble metal nanoparticles (e.g., Pt, Pd, and Au) on the surface of MOS can improve its selectivity. Herein, ZnO nanowires decorated with AuPt bimetallic nanoparticles are designed and fabricated on MEMS for H2S detection. The AuPt@ZnO nanowires-based sensor shows a response of 17.7–20 ppm H2S at 300 °C which is 4.0 times higher than that of pristine ZnO nanowires-based sensor. The sensor also exhibits a rapid response-recovery process, brilliant long-term stability, and excellent selectivity to H2S among various interfering gases. The remarkable improvement of the sensing performance, especially selectivity, could be ascribed to the electronic and chemical sensitization and the synergistic effect of the AuPt bimetal. Thus, the AuPt@ZnO nanowires-based sensor has a great potential application for H2S detection.

AuPt Bimetallic Nanozymes for Enhanced Glucose Catalytic Oxidase.

Au metal nanoparticles as artificial nanozymes have attracted wide interest in biotechnology due to high stability and easy synthesis. Unfortunately, its catalytic activity is limited by the uniform surface electron distribution, fundamentally affecting the oxidation efficiency of glucose. Here, we synthesized AuPt bimetallic nanoparticles with unique surface electron structure due to the coupling effect of the two metal components, achieving improved glucose catalytic oxidase. Because of the effective work function difference between the two metals in AuPt, the electrons will transfer from Au to accumulate on Pt, simultaneously contributing to the substantial enhancement of Au-induced glucose oxidase and Pt-induced catalase performance. We systematically studied the enzyme-catalytic efficiency of AuPt with varied two metal proportions, in which Au:Pt at 3:1 showed the highest catalytic efficiency of glucose oxidase in solution. The AuPt nanoparticles were further co-cultured with cells and also showed excellent biological activity for glucose oxidase. This work demonstrates that the physicochemical properties between different metals can be exploited for engineering high-performance metal nanoparticle-based nanozymes, which opens up a new way to rationally design and optimize artificial nanozymes to mimic natural enzymes.

MOF Encapsulated AuPt Bimetallic Nanoparticles for Improved Plasmonic-induced Photothermal Catalysis of CO2 Hydrogenation.

Exploring new catalytic strategies for achieving efficient CO2 hydrogenation under mild conditions is of great significance for environmental remediation. Herein, a composite photocatalyst Zr-based MOF encapsulated plasmonic AuPt alloy nanoparticles (AuPt@UiO-66-NH2 ) was successfully constructed for the efficient photothermal catalysis of CO2 hydrogenation. Under light irradiation at 150 °C, AuPt@UiO-66-NH2 achieved a CO production rate of 1451 μmol gmetal -1 h-1 with 91 % selectivity, which far exceeded those obtained by Au@Pt@UiO-66-NH2 with Pt shell on Au (599 μmol gmetal -1 h-1 ) and Au@UiO-66-NH2 (218 μmol gmetal -1 h-1 ). The outstanding performances of AuPt@UiO-66-NH2 were attributed to the synergetic effect originating from the plasmonic metal Au, doped active metal Pt, and encapsulation structure of UiO-66-NH2 shell. This work provides a new way for photothermal catalysis of CO2 and a reference for the design of high-performance plasmonic catalysts.

Au-Pt Bimetallic Nanoparticles Anchored on Conducting Polymer: An Effective Electrocatalyst for Direct Electrooxidation of Sodium Borohydride in Alkaline Solution

Au-Pt Bimetallic Nanoparticles Anchored on Conducting Polymer: An Effective Electrocatalyst for Direct Electrooxidation of Sodium Borohydride in Alkaline Solution

H2O-assisted O2 reduction by H2 on Pt and PtAu bimetallic nanoparticles: Influences of composition and reactant coverages on kinetic regimes, rates, and selectivities

Hydrogen peroxide (H2O2) can replace hazardous oxidants in industrial processes but is currently too expensive for many such applications. While direct synthesis of H2O2 (H2 + O2 → H2O2) may reduce costs in comparison to incumbent technology, current catalysts lack the requisite stability and selectivity. Here, we examine the direct synthesis of H2O2 on bimetallic Pt1Aux (0 ≤ x ≤ 230) and Pt catalysts at steady-state in pure water and relate kinetic parameters for H2O2 and H2O formation to possible active site structures informed by complementary characterization methods. X-ray photoelectron spectra show significant Pt surface enrichment compared to the bulk composition. Analysis of infrared spectra of mixed monolayers of 12CO* and 13CO* indicate that Pt and Au form substitutional surface alloys. The Pt1Aux nanoparticles with the greatest mole fractions of Au predominantly expose Pt monomers (i.e., isolated Pt atoms), yet Pt atoms exposed upon all these nanoparticles possess electronic structures distinct from bulk Pt. Despite these differences, rate measurements are consistent with product formation through proton-electron transfer pathways for all Pt1Aux catalysts. In situ XAS indicate that Pt remains metallic during H2O2 synthesis. Under the most oxidizing conditions, selectivities toward H2O2 increase strongly with the Au to Pt ratio from 2% for monometallic Pt to 85% for Pt1Au170. However, selectivities are similar among all catalysts within reducing conditions. Comparisons of apparent activation enthalpies for the formation of H2O2 and H2O across these catalysts and the range of conditions suggest that Pt monomers within Au provide the greatest selectivities for H2O2 formation, because these active sites present high barriers for O-O bond rupture. Selectivities decrease with increasing ratios of H2 to O2 pressures, because Pt atoms aggregate and form oligomers that readily dissociate dioxygen intermediates. The combined use of spectroscopy, kinetics, and concepts employed in reaching these conclusions take inspiration from the legacy of Prof. Michel Boudart, and specifically his elegant methods for interrogating bimetallic catalysts.

Enhanced nonlinear and thermo optical properties of laser synthesized surfactant-free Au-Pt bimetallic nanoparticles

The Au and Pt nanoparticles were synthesized employing laser ablation in water. Ligand-free Au-Pt bimetallic nanoparticles were generated by means of laser irradiation of the colloidal mixture of Au and Pt nanoparticles. The nonlinear optical characteristics like nonlinear absorption coefficient, nonlinear refractive index, optical limiting threshold and non linear optical susceptibility of Au, Pt, their colloidal mix and bimetallic nanoparticles were determined via Z scan method. All nanoparticle samples exhibited strong reverse saturable absorption behaviour with positive value of nonlinear absorption coefficient and strong optical limiting efficiency. The non linear absorption and refraction characteristics were found to be considerably enhanced for the Au-Pt bimetallic nanoparticles than the corresponding mono metallic nanoparticles and the pre-irradiation colloidal mix. The thermo optical features were also studied using thermal lens method and found to be tunable by controlling the fraction of Au and Pt in the bimetallic nanoparticles. To the best knowledge of the authors, it is presumed that, the present work is the first report on the non linear and thermo optical characterization of Au-Pt bimetallic nanoparticles. The present work has significance in nonlinear optical and photo thermal applications like optical limiting, photo thermal therapy and photo acoustic imaging.

Engineering a multiscale multifunctional theragenerative system for enhancing osteosarcoma therapy, bone regeneration and bacterial eradication

Osteosarcoma as an aggressive malignant neoplasm is one of the formidable challenging diseases clinically. The related tumor recurrence, large bone defects, and postoperative bacterial infection after surgical resection of osteosarcoma are pressing problems that still threaten patient health. Herein, a multiscale multifunctional theragenerative system (Fs-NFs-AuPt) is designed based on NiTi alloys for near-infrared-activated photothermal ablation of osteosarcoma, bone repair, and antibacterial. To achieve this aim, first, a useful methodology is proposed that employs temporally shaped femtosecond laser ablation combined with hydrothermal synthesis to fabricate multiscale hierarchical structures (Fs-NFs) consisting of three-dimensional micro-nanostructures (Fs-NiTi) and nanoflower-like structures (NFs) for promoting osteogenicity. Then, AuPt bimetallic nanoparticles as satisfactory photothermal therapy agents and osteoinductive agents are rapidly (only need 30 s) one-step in-situ synthesized on Fs-NFs through ultraviolet photoreduction without any reductant. Fs-NFs-AuPt significantly ablates tumors cells (Saos-2 and MDA-MB-231) in vitro, effectively inhibits osteosarcoma growth in mice, and positively induces the osteogenesis of osteoblasts (MC3T3-E1). Moreover, it exhibits superior antibacterial efficiencies of 99.5% and 99.8% against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Overall, this work offers a high-efficiency, high-quality, and high-repeatability distinctive integrated fabrication avenue to construct a multiscale multifunctional theragenerative system for osteosarcoma therapy and bone-tissue engineering.

A Study on the Splitting of Large Gold Nanoparticles by Addition of Aqueous Ascorbic Acid

Control of the size and shape of nanoparticles significantly impacts the ability to control their physical and chemical properties. In this paper, we introduce a technique to split large nanoparticles into smaller ones. After the addition of ascorbic acid (AA), 50 nm-sized gold (Au) nanoparticles in the form of polycrystals were split into nanoparticles with sizes of 10 nm. We believe that AA plays a critical role in breaking down the Au particles. Additionally, this technique can be used to synthesize small AuPt bimetallic nanoparticles with a small amount of Pt on their surface showing that this reaction could help in the formation of a variety of small Au-based bimetallic nanoparticles.

AuPt Bimetal-Functionalized SnSe2 Microflower-Based Sensors for Detecting Sub-ppm NO2 at Low Temperatures.

A novel chemiresistive-type sensor for detecting sub-ppm NO2 has been fabricated using AuPt bimetal-decorated SnSe2 microflowers, which was synthesized by the hydrothermal treatment followed by in situ chemical reduction of the bimetal precursors on the surface of the petals of the microflowers. The as-prepared sensor registers a superior performance in detection of sub-ppm concentration of NO2. Functionalized by the AuPt bimetal, the SnSe2 microflower-based sensor shows a response of approximately 4.62 to 8 ppm NO2 at 130 °C. It is significantly higher than those of the sensors using the pristine SnSe2 (∼2.29) and the modified SnSe2 samples by a single metal, either Au (∼3.03) or Pt (∼3.97). The sensor demonstrates excellent long-term stability, signal repeatability, and selectivity to some typical interfering gaseous species including ammonia, acetone, formaldehyde, ethanol, methanol, benzene, CO2, SO2, and CO. The remarkable improvement of the sensitive characteristics could be induced by the electronic and chemical sensitization and the synergistic effect of the AuPt bimetal. Density functional theory (DFT) is implemented to calculate the adsorption states of NO2 on the sensing materials and thus to possibly reveal the sensing mechanism. The significantly enhanced response of the SnSe2-based sensor decorated with AuPt bimetallic nanoparticles has been found to be possibly caused by the orbital hybridization of O, Au, and Pt atoms leading to the redistribution of electrons, which is beneficial for NO2 molecules to obtain more electrons from the composite material.

DNA/Au-Pt bimetallic nanoparticles/graphene oxide-chitosan composites modified pencil graphite electrode used as an electrochemical biosensor for sub-picomolar detection of anti-HIV drug zidovudine

Zidovudine (ZDV) has been widely employed in the human immunodeficiency virus type 1 (HIV-1) infection treatment. The short half-life, side effects of high doses, and adverse effects of ZDV necessitate the existence of a fast, simple, and reliable analysis method. In this work, a modified pencil graphite electrode was made using deoxyribonucleic acid/Au-Pt bimetallic nanoparticles/graphene oxide-chitosan (DNA/Au-Pt BNPs/GO-chit/PGE) for the determination of ZDV. Initially, the bare PGE was immersed in the GO-chit solution to create the graphene oxide-chitosan/pencil graphite electrode (GO-chit/PGE). Subsequently, electrodeposition of Au-Pt bimetallic nanoparticles (Au-Pt BNPs) was accomplished on the surface of GO-chit/PGE modified electrode by cyclic voltammetry (CV). Ultimately, DNA was immobilized on the Au-Pt BNPs/GO-chit/PGE applying a constant potential 0.5 V. The electrochemical response of ZDV upon the DNA/Au-Pt BNPs/GO-chit/PGE was measured by applying differential pulse voltammetry (DPV). In the optimum conditions, the proposed sensor displayed a wide linear dynamic range from 0.01 pM to 10.0 nM, a detection limit of 0.003 pM, and high selectivity and well reproducibility. Furthermore, the DNA/Au-Pt BNPs/GO-chit/PGE was successfully utilized to determine ZDV in human serum samples.

Two birds with one stone: oyster mushroom mediated bimetallic Au-Pt nanoparticles for agro-waste management and anticancer activity.

Agriculture has the most significant contribution in fulfilling the basic human need, sustaining life, and strengthening the economy of any country. To feed the exploding population of the world, there has been a quantum jump in the production of agricultural commodities, which has led to the production of a substantial considerable quantity of agricultural and agro-industrial wastes. The bulks of these wastes are lignocellulosic in nature and consist of three main polymeric constituents, i.e., cellulose, hemicellulose, and lignin, which are recalcitrant. The primary significant portions of these remain unutilized and are burnt in the field, leading to severe environmental aggression and wastage of resource. Farmers across the globe, including India, burn these agricultural wastes in their thousands of acre land, which contribute to spoiling the air quality index (AQI). This is very harmful, especially to children, pregnant women, old adults, and for patients suffering from respiratory diseases. The current manuscript sets up an agro-waste management platform by using paddy straw as a substrate for the production of nutritionally and medically rich oyster mushroom, Pleurotus florida (Pf) and which is further used in the green synthesis of bimetallic (gold-platinum) Au-Pt nanoparticle. Yield performance and biological efficiency of Pf were calculated from the degraded paddy straw. The green synthesized Au-Pt NPs were structurally characterized by ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and zeta potential analysis. The prepared NPs showed a face-centered cubic crystal structure, icosahedral shape with a mean particle size of 16nm. Furthermore, we examined the cytotoxic activity of Au-Pt NPs using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, intracellular reactive oxygen species (ROS) generation, and apoptosis by propidium iodide assay. We found that Au-Pt NPs exerted apoptotic activity on the human colon cancer cell line (HCT 116) in a dose-dependent manner from 12.5 to 200μg/mL. Overall, our findings create a prototype and open a new door to synthesizing functional nanoparticle by using oyster mushroom as the substrate for paddy straw agro-waste management and the applicability of Pf in the synthesis of eco-friendly Au-Pt NPs. This is the first kind of approach that kills two birds with one stone.

Agglomerates of Au-Pt bimetallic nanoparticles: synthesis and antibacterial activity

The extraction of bimetallic Au-Pt nanoparticles is interesting due to their multiple applications in catalytic processes, electronic devices, photothermal therapies, among others. On the other hand, the tendency of nanoparticles forming agglomerates may modify the behavior of the material, and thus their applications. This study shows a highly reproducible novel synthesis method, which only uses two organic agents (sucrose and ascorbic acid) as the reducing and stabilizing agents from nano-agglomerates of Au-Pt at room temperature. The TEM images show agglomerates with a mass fractal structure. We identified crystalline FCC, corresponding to the Au-Pt alloy. Furthermore, the coexistence of gold and platinum nanoparticles was shown through the EDS analysis. The UV-Vis spectrum showed that the resonance plasmon identified coincides with a great approximation to the results reported in the literature. Additionally, the agglomerates exhibited excellent antibacterial activity against bacteria Escherichia coli.