Platinum Bimetallic Nanoparticles Research Articles

Synthesis of Ecofriendly Bimetallic Pt/Ni Nanoparticles on KNbO3 via Hydrothermal Process for Sustainable Hydrogen Evolution from NaBH4

The performance of nickel and platinum bimetallic nanoparticles (NPs) supported on potassium niobate (KNbO3) is evaluated in the catalytic hydrolysis of sodium borohydride (NaBH4) to generate hydrogen (H2). KNbO3 was synthesized via a hydrothermal route using Nb2O5 and KOH as precursors. X-ray diffraction (XRD) confirmed the crystalline orthorhombic structure of KNbO3. The Ni/Pt NPs, with an average size of 4.66 nm and a spherical morphology, were uniformly dispersed on the surface of KNbO3 nanosheets. The N2 physisorption isotherms of KNbO3 and Ni/Pt NPs were classified as type V with H3 hysteresis, showing specific surface areas of 0.170 and 2.87 m2 g−1, respectively. Catalytic performance studies examined various Ni/Pt molar ratios, with the 1:3 ratio (mol/mol) demonstrating the highest efficiency. Kinetic analysis of NaBH4 hydrolysis showed that the data fit the pseudo-first-order model. An increase in temperature enhanced the hydrogen generation rate (HGR), reaching 2068.3 mL gcat−1 min−1 at 315.05 K. The apparent activation energy (Ea) was determined to be 29.9 kJ mol−1. Durability assays showed only an 11% decrease in activity after 11 catalytic cycles. Thus, a promising, easy-to-synthesize, and environmentally friendly catalyst for NaBH4 hydrolysis has been developed.

MIL-101(Cr) entrapped polyol-synthesized iron promoted platinum bimetallic nanoparticles system for synergistic selective hydrogenation of cinnamaldehyde

The interfacial characteristics of platinum (Pt) metal catalysts can be systematically regulated by interacting them with electropositive metals, leading to synergistic interactions for extensive catalytic applications. In this study, an evenly dispersed polyol-synthesized iron (Fe)-promoted Pt bimetallic nanoparticle (BNPs) system was embedded in MIL-101(Cr). The PtFe2@MIL-101(Cr) catalyst unveiled remarkable activity (86%) and selectivity (89%) for the superior hydrogenation of the targeted CO bond of cinnamaldehyde (CAL). The exceptional hydrogenation performance can be credited to the interplay of the geometric and electronic properties arising from charge shuttling between Fe and Pt within the homogenously distributed Pt–Fe bimetallic nanoparticle system. The experimental results indicate enhanced valence electrons in the Pt d-band through the mutual synergetic interface between the Pt and Fe BNPs. Consequently, these Fe–Pt sites functioned as interfacial electrophilic and nucleophilic (Lewis acid-base) sites, enhancing H2 activation and facilitating CO bond conversion to yield unsaturated cinnamal alcohols (COL). Additionally, the narrow pores of MIL-101(Cr) encapsulating the Pt–Fe BNPs induced steric hindrance, allowing only CO bond hydrogenation. Furthermore, the PtFe2@MIL-101(Cr) catalyst maintained its optimal hydrogenation performance over five cycles, demonstrating no substantial loss in either CAL conversion or COL yield, thus endorsing the universal practical applicability of the catalyst.

Phytochemical-Stabilized Platinum-Decorated Silver Nanocubes INHIBIT Adenocarcinoma Cells and Enhance Antioxidant Effects by Promoting Apoptosis via Cell Cycle Arrest.

(1) Background: The increasing use of silver and platinum bimetallic nanoparticles in the diagnosis and treatment of cancer presents significant advances in biomedical applications due to their extraordinary physicochemical properties. This study investigated the role of aqueous phytochemical extract in stabilizing platinum nanodots-decorated silver nanocubes (w-Pt@AgNPs) for enhancing antioxidant activities and their mechanism. (2) Methods: UV-Vis, Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM) were used to characterize the formed w-Pt@AgNPs. LC-QToF-MS/MS was used to analyze the bioactive compounds, while DPPH, ABTS, and FRAP were used to detect the scavenging potential. Flow cytometric assays were performed to investigate the cytotoxicity and the mechanism of cell death. (3) Results: Morphological studies indicated that w-Pt@AgNPs were cube in shape, decorated by platinum nanodots on the surfaces. Compared to ethanolic extract-synthesized e-Pt@AgNPs, w-Pt@AgNPs exhibited the strongest antioxidant and cytotoxic activity, as data from Annexin V and Dead cell labeling indicated higher induction of apoptosis. Despite the high proportion of early apoptotic cells, the w-Pt@AgNPs triggered a decrease in G1/G0 cell cycle phase distribution, thereby initiating a G2/M arrest. (4) Conclusions: By enhancing the antioxidant properties and promoting apoptosis, w-Pt@AgNPs exhibited remarkable potential for improved cancer therapy outcomes.

Exciton-mediated surface-enhanced Raman studies of Aluminum doped platinum nano colloids

In this article, we report the fabrication of Aluminum doped Platinum bimetallic nanoparticles (NPs) by ultrafast laser ablation (using femtosecond laser pulses of duration ∼50 fs, central maximum 800 nm) of Aluminum (Al) target immersed in Platinum (Pt) colloidal solutions in Isopropanol. Colloidal solutions of Pt NPs at a concentration of 0.5 mM, 1 mM, 3 mM, and 7 mM were prepared in Isopropyl alcohol and exhibited localized surface plasmon resonances (LSPR) at ∼292 nm. However, the LSPRs of Al-doped Pt colloids were modified to ∼283 nm (0.5 mM Pt), ∼226 nm (1 mM Pt) ∼226 nm (3 mM Pt) ∼228 (7 mM Pt). Average sizes of Al-doped Pt colloidal NPs synthesized by the ablation of Al metal targets immersed in 0.5 mM Pt, 1 mM Pt, 3 mM Pt, and 7 mM Pt colloids were estimated to be ∼19.5 nm, ∼11 nm, ∼12 nm, and ∼13.5 nm, respectively. These Al-doped Pt NPs are employed in surface-enhanced Raman scattering (SERS) studies of Methylene Blue (MB) dissolved in IPA at 0.5 μM, 5 μM, and 50 μM concentrations. Although the SPR strength of Pt and Al are moderate, the annihilation of the excitons created in Al-doped Pt NPs might lead to the formation of the charge carriers, enhancing the population in the conduction band and strengthening the SPR, finally leading to a significant SERS enhancement. The estimated enhancement factors for the mode 1623 cm−1 correspond to MB's highly elevated vibrational mode are ∼105. This article is the first report of its kind on SERS of Al-doped Pt NPs to the best of our knowledge.

Highly active PdPt bimetallic nanoparticles synthesized by one-step bioreduction method: Characterizations, anticancer, antibacterial activities and evaluation of their catalytic effect for hydrogen generation

Metallic nanoparticles (MNPs) have important applications in medicine and technology. Bimetallic NPs, which are among the metallic nanoparticles, are of great interest due to their properties. An innovative method by green synthesis has been developed to obtain bimetallic NPs. Aromatic plants are used in this synthesis method. One of the plants used for green synthesis is Nigella sativa and it has a unique place among plants for use as medicine. In this study, the synthesis of Palladium–Platinum bimetallic nanoparticles (PdPt NPs) and the catalytic, antibacterial, and anticancer activity of synthesized PdPt NPs by green synthesis method using Nigella sativa seed extract are reported. The synthesized PdPt NPs were characterized by Fourier Transform Infrared Spectrophotometer (FTIR), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and UV–Vis spectrometry techniques. The catalytic activity of PdPt NPs was determined by performing sodium borohydride (NaBH4) hydrolysis experiments. According to the results obtained, Turnover Frequency (TOF), activation energy, entropy, and enthalpy values were found to be 1664.76 h−1, 13.93 kJ/mol, −119.02 J/mol.K, and 11.43 kJ/mol, respectively. It was determined that PdPt NPs are highly effective catalysts for hydrogen production. PdPt NPs (200 μg/mL) were determined to have antibacterial activity of 57.58%, 64.42%, 48.68%, and 58.77% against Escherichia coli, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, and Bacillus subtilis bacteria, respectively. In addition, the cytotoxic effects of PdPt NPs, MTT against human breast cancer cell line (MDA-MB-231), human endometrial carcinoma cell line (Ishikawa, ISH), human cervical cancer cell line (HeLa), L929-Murine fibroblast cell line test, and IC50 values were calculated. The IC50 values of PdPt NPs applied against MDA-MB-231, ISH, and HeLa cancer cell lines were calculated as 9.1744 ± 1.566 μg/mL, 12.2431 ± 1.132 μg/mL, 18.1963 ± 1.730 μg/mL, respectively. No significant cytotoxic effect was observed in healthy L929-murine fibroblasts. Green synthesis of PdPt NPs was determined to have significant advantages over chemical approaches. The biogenic PdPt NPs synthesized in this study suggest the design of bio-based bimetallic catalysts with high catalytic performance to prevent environmental pollution.

Non-enzymatic lactic acid sensor based on AuPtNPs functionalized MoS2 nanosheet as electrode modified materials

Lactic acid (LA) is an energy product of anaerobic metabolism and also used as an important biomarker in clinical medical diagnosis. Herein, a facile and efficient non-enzymatic electrochemical sensor had been successfully developed to determine LA using gold platinum bimetallic nanoparticles modified molybdenum disulfide nanosheet (MoS 2 -AuPt) as a sensing platform. The presence of AuPtNPs not only increased the electron transfer rate but also could replace enzymes for electrochemical oxidation of LA. Thus, MoS 2 -AuPt could be acted as an efficient electrocatalyst for non-enzymatic LA detection. Finally, the non-enzymatic LA sensor was used to detect different concentrations of LA, its linear range was 0.005–3 mM, the detection limit was 0.00033 mM, and the response time was less than 15 s. Moreover, the developed LA sensor had been successfully applied to detect LA in human sweat, which provided a broad prospect for the analysis of LA in some other complicated samples.

Electrochemical biosensor for miRNA-21 based on gold-platinum bimetallic nanoparticles coated 3-aminopropyltriethoxy silane

We report an electrochemical biosensor based on gold platinum bimetallic nanoparticles (AuPtBNPs)/3-aminopropyltriethoxy silane (APTS) nanocomposite coated fluorine-doped tin oxide (FTO) as a biosensing platform for hybridization-based detection of miRNA-21. Field Emission-Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and electrochemical measurements were carried out to ensure the successful construction of the biosensor. The amount of cDNA immobilized on electrode surface and hybridization time required for the miRNA-21 sensing were optimized. The biosensing platform showed detection limit of 0.63 fM with wide linear range i.e. 1 fM-100 nM for miRNA-21 detection. The biosensing strategy demonstrates a good recovery yield from 90.18% to 94.6% in serum samples. It offers good selectivity for its complementary miRNA compared to the non-complementary miRNAs. Other analytical features of the biosensor such as stability, reusability and reproducibility were also tested, providing appropriate results.

Application of Gold and Platinum Bimetallic Nanoparticle to enhance Surface Plasmon Resonance Signal

Sensors based on the surface plasmon resonance (SPR) technique are useful devices to detect and monitor interactions between biomolecules in real-time. SPR is a label-free method that monitors the variation of reflectivity of a biochip composed of a metal-coated glass prism and can be applied in several areas, such as biotechnology, food safety and clinical diagnosis. In the last years, several researchers have proven the efficiency of metallic nanoparticles (NPs) in the enhancement of SPR signal. This feature allowed the detection of biomolecules at very low concentration. Aiming to further enhance SPR signal towards the detection of proteins at low concentration and by a simple procedure, the present work compared the performance of gold and platinum bimetallic NPs (AuPtNPs) with that of monometallic gold NPs (AuNPs) in the enhancement of SPR signal. In order to evaluate the NPs, protein peanut agglutin (PNA) was used as target analyte and anti-PNA antibody was used as sensing molecule. Firstly NPs were functionalized with anti-PNA antibody and incubated with a solution containing PNA. Then, the NPs bound to PNA were injected into the SPR equipment containing a biochip previously modified with anti-PNA antibody. The results demonstrated that the AuPtNPs provided a 91-fold increase compared to the direct detection of free PNA in solution. In comparison with AuNPs, the signal generated by AuPtNPs was about 4 times higher. This encouraging result indicated that the application of bimetallic NPs may be a better strategy to further enhance sensitivity of SPR biosensors and could drive the development of new strategies that are not only simple, but also able to detect proteins at low concentrations, which is of great importance, especially in clinical diagnostics.

An electrochemical aptasensor for analysis of MUC1 using gold platinum bimetallic nanoparticles deposited carboxylated graphene oxide

A simple electrochemical strategy has been designed for the analysis of MUC1 using electrodeposited gold platinum bimetallic nanoparticles (Au-PtBNPs) on the surface of carboxylated graphene oxide (CGO)/FTO electrode as a signal amplification platform. The carboxylic groups of CGO were activated with EDS-NHS linker and subsequently immobilized with streptavidin for further deposition of biotin labelled aptamer. All the modification steps were characterized by FE-SEM, EDS mapping, FT-IR, contact angle measurements and electrochemical methods. After incubating with target protein MUC1, the aptaelectrode produced some concentration dependent responses which were measured electrochemically by DPV assay. The prepared aptasensor exhibits wide linear range from 1 fM-100 nM with detection limit of 0.79 fM under optimal experimental conditions. The performance of this aptaelectrode was also evaluated showing good selectivity, storage stability (15 days), reproducibility and reusability (up to 3 times). Furthermore, the applicability of the aptasensor for spiked serum samples showed recovery range from 92% to 97%.

An unplugged and quantitative foam based immunochromatographic assay for Escherichia coli O157:H7 using nanozymes to catalyze hydrogen peroxide decomposition reaction

Quantitative and portable detection of target without skilled personnel and equipment is an important research focus in point-of-care testing field. A cost-effective, portable and unplugged foam immunochromatographic assay (Foam-ICA) for on-site and quantitative detection of Escherichia coli O157:H7 (E. coli O157:H7) without any instrument was reported. In sample solution the detection target E. coli O157:H7 were captured and labeled by monoclonal antibody modified the gold platinum bimetallic nanoparticles (anti-E. coli O157:H7 mAb Au@Pt NP). And horse radish peroxidase (HRP) was loaded on Au@Pt NP instead of BSA to block the active site. In this way, catalytic activity of Au@Pt NP was further enhanced and the final signal was further amplified. After addition of positive sample, anti-E. coli O157:H7 mAb modified Au@Pt NP are captured in the test (T) line by antibody-antigen recognition. And then the T line zone cut and added to hydrogen peroxide (H2O2) to catalyze decomposition of H2O2 to oxygen (O2) in 96-well plates. Produced O2 gas is trapped by sodium dodecyl sulfate (SDS) forms large amount of foam, which converts the E. coli O157:H7 amount into foam height with a reaction time of 8 min at 50 °C. The linear range of Foam-ICA for detecting E. coli O157:H7 is from 1.93 × 104 to 1.93 × 108 CFU mL−1, and the limit of detection (LOD) was 1.83 × 104 CFU mL−1 (3σ). The LOD of Foam-ICA for E. coli O157:H7 can be further enhanced to 1 CFU mL−1 by pre-incubation of the samples for 8 h. Thus, the Foam-ICA may be used for quantitative and cost effective detection of target without electrical instruments.

Electrochemical Fingerprint of Arsenic (III) by Using Hybrid Nanocomposite-Based Platforms.

Arsenic, one of the most abundant mineral and also one to the most toxic compounds. Due to its high toxicity sensitive analytical methods are highly important, taking into account that the admitted level is in the range of µg L−1. A novel and easy to use platform for As(III) detection from water samples is proposed, based on gold and platinum bi metallic nanoparticles and a conductive polymer (polyaniline). The electrochemical detection was achieved after optimization of cathodic pre-concentration and stripping parameters by square wave anodic stripping voltammetry at modified screen-printed carbon-based electrochemical cells, proving its applicability for disposable and cost-effective in situ analysis of arsenic.

Fabrication of a new electrochemical sensor based on Au[sbnd]Pt bimetallic nanoparticles decorated multi-walled carbon nanotubes for determination of diclofenac

A new electrochemical sensor was developed for determination of diclofenac based on functionalized multi-walled carbon nanotubes (f-MWCNTs) and gold–platinum bimetallic nanoparticles (Au–PtNPs) modified gold electrode. The Au–PtNPs were deposited electrochemically on the surface of the f-MWCNTs modified electrode. The surface morphologies of the modified electrodes were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical properties of the constructed sensor. Under the optimized experimental conditions, the calibration curve was linear in the concentration range of 0.5 μM to 1000 μM of diclofenac and the detection limit was found to be 0.3 μM. The developed electrode also showed a high selectivity for diclofenac in the presence of the interfering species. The reproducibility, repeatability and stability of the electrode were satisfactory. The proposed electrochemical sensor was successfully employed for determination of diclofenac in real samples such as tablet and human urine samples.

Application of bimetallic nanoparticles modified screen printed electrode for the detection of organophosphate compounds using an enzyme inhibition approach

A novel, unique gold–platinum bimetallic nanoparticles modified screen printed electrode (SPE) has been developed for the sensitive detection of paraoxon ethyl, carbofuran and simulant of nerve agent diisopropyl fluorophosphate (DFP), based on the enzyme inhibition approach. The gold–platinum nanoparticles were electrochemically deposited on a 3-aminopropyl triethoxy silane modified electrode. Following this acetylcholineesterase (AChE)/choline oxidase (ChOx) bienzymes were immobilized through cross-linking with glutaraldehyde onto a modified electrode. Electrodes were characterized by scanning electron microscopy (SEM), EDX (energy dispersive X-ray analysis) and cyclic voltammetry (CV). The bimetallic alloy nanoparticles have an excellent high surface area and the unique effect of electrocatalytic activity for the oxidation of hydrogen peroxide (H2O2). The IC50 values were determined for the inhibitors using immobilized enzymes on the modified electrode. Paraoxon ethyl, carbofuran, and DFP could be detected up to 0.20 μM, 0.20–0.25 μM, and 0.20–0.25 μM respectively at a 25–30% inhibition level of AChE enzyme (residual enzyme activity) with an incubation time of 10 min.

Immobilization of acetylcholineesterase–choline oxidase on a gold–platinum bimetallic nanoparticles modified glassy carbon electrode for the sensitive detection of organophosphate pesticides, carbamates and nerve agents

A novel, highly sensitive amperometric biosensor, based on electrodeposition of gold–platinum bimetallic nanoparticles onto 3-aminopropyltriethoxy silane modified glassy carbon electrode for the detection of paraoxon ethyl, aldicarb, and sarin has been developed. The biosensor consists of acetylcholineesterase (AChE)/choline oxidase (ChOx) immobilized by cross-linking with glutaraldehyde on a modified electrode. The properties of nanoparticles modified electrodes are characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS). The synergistic action of Au and Pt nanoparticles showed excellent electrocatalytic activity with low applied potential for the detection of hydrogen peroxide (H2O2). The IC50 and inhibition rate constant (Ki) values were determined for the inhibitors using immobilized enzymes on modified electrode and the data were compared by spectrophotometric determination of these kinetic parameters using free enzymes in solution. Paraoxon ethyl, sarin, and aldicarb could be detected up to 150–200nM, 40–50nM, and 40–60μM respectively at 30–40% inhibition level of AChE enzyme and followed linearity in wide range concentration.