Synthesis Of Platinum Nanoparticles Research Articles

An improved amperometric cholesterol biosensor based on cholesterol oxidase nanostructures for pre-diagnosis of myocardial infarction

Cholesterol plays a pivotal role in human health, serving as a crucial biomarker for cardiovascular diseases, including myocardial infarction. This study presents the development of an innovative amperometric cholesterol biosensor that enhances the detection and quantification of cholesterol levels in serum. The biosensor integrates cholesterol oxidase (ChOx) nanoparticles with a modified electrode, leveraging the unique properties of platinum nanoparticles (PtNPs) and graphene nanosheets (GNs) to improve sensitivity and stability. The synthesis of PtNPs was achieved using Camellia sinensis extract, while graphene oxide was reduced to form GNs. At 2.39 mg/mL or above is deemed a biomarker for cardiovascular disorders, peripheral artery disease, heart attack, diabetes mellitus, strokes, and hypertension. The monitoring of serum cholesterol level is therefore very significant. In the present study, an innovative amperometric cholesterol biosensor was constructed by immobilizing nanoparticles of cholesterol oxidase onto a pencil graphite (PG) electrode modified with graphene nanosheets (GNs), platinum nanoparticles (PtNPs), and chitosan (CHIT). At various stages of construction, the modified electrode was characterized by employing electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. The biosensor responded best when run at 0.14Vs-1 at optimal pH and temperature of 8.0 and 35°C respectively. The biosensor has a wide linear range (0.1mg/mL-7.5 mg/mL), with great sensitivity (0.89 mA cm−1mgmL−1) and a low limit of detection (0.97 mg/mL). This research not only contributes to the field of biosensing but also offers a promising tool for the early diagnosis of cholesterol-related health issues, paving the way for enhanced cardiovascular disease management.

Environmentally-friendly synthesis of platinum nanoparticles: phytochemical, antioxidant, and antimicrobial properties of Cichorium intybus in different solvents

Cichorium intybus, a medicinal plant from the Asteraceae family, has long been utilized in traditional medicine across South and North Africa. This study explores the phytochemical profile, antioxidant, and antimicrobial activities of C. intybus leaf extracts and develops a green synthesis method for platinum nanoparticles (PtNPs) using these extracts. Extracts were prepared using five solvent systems: 80% methanol, 80% ethanol, 100% methanol, 100% ethanol, and de-ionized water. The 80% methanolic extract showed the highest yield (12.79 g/100 g DW), total phenolic content (93.24 mg GAE/g DW), and total flavonoid content (8.92 mg CE/g DW). Antioxidant activity assays revealed that the 80% methanolic extract had the highest DPPH radical scavenging activity and reducing power. Additionally, the green synthesis of PtNPs was achieved using C. intybus extracts, indicated by a color change and a surface plasmon resonance band at 295 nm in UV–visible spectroscopy. Optimal synthesis conditions were pH 9, 120 min reaction time, and 90 °C. UV–visible and FTIR spectroscopy confirmed the synthesis and stability of the PtNPs. These findings highlight the medicinal importance of Cichorium intybus and present a sustainable approach for synthesizing platinum nanoparticles, offering significant contributions to phytochemistry and nanotechnology.

Green synthesis of platinum nanoparticles using aqueous bark extract of Quercus sp. for potential antioxidant and antimicrobial applications

Oak bark, which is commonly used in the wood industry, has by-products often repurposed as fuel. Its extracts are rich in compounds with anticancer, antibacterial, antifungal, and anti-inflammatory properties. This study synthesized platinum nanoparticles (PtNPs) using aqueous extracts from Quercus dalechampii (QD), Q. frainetto (QF), and Q. petraea (QP). Key factors during nanoparticle formation included reaction time, metal ion concentration, pH, extract-to-metal ion ratio, and temperature. The PtNPs were characterized by dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The average diameters were 58.5 ± 7.6 nm for QD-PtNPs, 41.6 ± 5.4 nm for QF-PtNPs, and 41 ± 5.3 nm for QP-PtNPs. Antioxidant and antimicrobial activities were also analyzed. The QP-PtNPs had the highest DPPH (2,2-Diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power), and CUPRAC (Cupric Reducing Antioxidant Capacity) free radical scavenging activities, while QD-PtNPs excelled in ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) scavenging. All PtNPs showed strong antimicrobial properties, particularly against Enterococcus faecalis, Escherichia coli, Candida krusei, and Candida auris. These findings suggest that Quercus-mediated PtNPs have significant potential for developing treatments against bacterial and fungal infections, with promising applications in medicine.

Screening the efficacy of platinum-based nanomaterial synthesized from Allium sativum to control plant pathogens

Emerging challenge posed by multidrug-resistant Bacillus spp. phytopathogens on agriculture and their commodities exerts pressure on global food security. This mandates the search for other alternatives to existing antibiotics. This study reports a novel method of green synthesis of platinum nanoparticles (PtHGNM) using aqueous extract of Himalayan garlic (Allium sativum). Physicochemical characterization techniques including UV-visible spectrometry, FT-IR, XRD, DLS, zeta potential, and FESEM-EDAX disclosed the biogenic fabrication of a stable and amorphic nano platinum material. This nanoparticle exhibited high bactericidal efficacy and effectively inhibited biofilm formation by the model plant-borne pathogens used in this study. We estimated the membrane integrity, oxidative enzymes and stress parameters of bacteria to elucidate the underlying mechanism of action of PtHGNM. This research uncovered the potential of biogenic nanoparticles for sustainable plant disease management and paved the way for further analysis of its properties and mechanism of its action.

Platinum nanoparticle oxidase-like enzyme for colorimetric and photothermal dual-mode detection of sulfide ions

Monitoring sulfide ions (S2-) in environmental matrices is critical for environmental safety and pollution control. In this work, a novel dual-mode colorimetric and photothermal (PT) point-of-care testing (POCT) platform was developed for S2- assay. The synthesized platinum nanoparticles (Pt NPs) exhibited exceptional oxidase-like activity, catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to its oxidized form (oxTMB), causing a color change from colorless to blue. Additionally, oxTMB exhibits significant PT effects under near-infrared 808 nm laser irradiation. The presence of S2- induced the aggregation of Pt NPs, markedly inhibiting their oxidase-like activity, thereby establishing an inverse relationship between the concentration of S2- and both the RGB value and temperature change in TMB solution. The limits of detection (LODs) were calculated to be 1.5 μM and 4.4 μM for colorimetric and photothermal analysis using a digital thermometer and smartphone, respectively. The S2- in lake water and fuel residue was analyzed, yielding satisfactory results. This method offers low-cost, straightforward, and swift advantages, underscoring its potential for POCT in environmental monitoring.

Non-Invasive Detection of Early-Stage Fatty Liver Disease via an On-Skin Impedance Sensor and Attention-Based Deep Learning.

Early-stage nonalcoholic fatty liver disease (NAFLD) is a silent condition, with most cases going undiagnosed, potentially progressing to liver cirrhosis and cancer. A non-invasive and cost-effective detection method for early-stage NAFLD detection is a public health priority but challenging. In this study, an adhesive, soft on-skin sensor with low electrode-skin contact impedance for early-stage NAFLD detection is fabricated. A method is developed to synthesize platinum nanoparticles and reduced graphene quantum dots onto the on-skin sensor to reduce electrode-skin contact impedance by increasing double-layer capacitance, thereby enhancing detection accuracy. Furthermore, an attention-based deep learning algorithm is introduced to differentiate impedance signals associated with early-stage NAFLD in high-fat-diet-fed low-density lipoprotein receptor knockout (Ldlr-/-) mice compared to healthy controls. The integration of an adhesive, soft on-skin sensor with low electrode-skin contact impedance and the attention-based deep learning algorithm significantly enhances the detection accuracy for early-stage NAFLD, achieving a rate above 97.5% with an area under the receiver operating characteristic curve (AUC) of 1.0. The findings present a non-invasive approach for early-stage NAFLD detection and display a strategy for improved early detection through on-skin electronics and deep learning.

Rational Construction of Pt Incorporated Co3O4 as High-Performance Electrocatalyst for Hydrogen Evolution Reaction.

Electrocatalysts in alkaline electrocatalytic water splitting are required to efficiently produce hydrogen while posing a challenge to show excellent performances. Herein, we have successfully synthesized platinum nanoparticles incorporated in a Co3O4 nanostructure (denoted as Pt-Co3O4) that show superior HER activity and stability in alkaline solutions (the overpotentials of 37 mV to reach 10 mA cm-2). The outstanding electrocatalytic activity originates from synergistic effects between Pt and Co3O4 and increased electron conduction. Theoretical calculations show a significant decrease in the ΔGH* of Co active sites and a remarkable increase in electron transport. Our work puts forward a special and simple synthesized way of adjusting the H* adsorption energy of an inert site for application in HER.

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Green Synthesis of Platinum Nanoparticles Using Polymer Bio-reduction Approach and Their Photocatalytic Organic Dye Degradation

Platinum nanoparticle synthesis in engineered organic nanoscale reactors for efficient oxygen electro-reduction in alkaline conditions

Platinum nanoparticle synthesis in engineered organic nanoscale reactors for efficient oxygen electro-reduction in alkaline conditions

Reduced graphene oxide-functionalized polymer microneedle for continuous and wide-range monitoring of lactate in interstitial fluid

Despite substantial developments in minimally invasive lactate monitoring microneedle electrodes, most such electrode developments have focused on either sensitivity or invasiveness while ignoring a wide range of detection, which is the most important factor in measuring the normal range of lactate in interstitial fluid (ISF). Herein, we present a polymer-based planar microneedle electrode fabrication using microelectromechanical and femtosecond laser technology for the continuous monitoring of lactate in ISF. The microneedle is functionalized with two-dimensional reduced graphene oxide (rGO) and electrochemically synthesized platinum nanoparticles (PtNPs). A particular quantity of Nafion (1.25 wt%) is applied on top of the lactate enzyme to create a diffusion-controlled membrane. Due to the combined effects of the planar structure of the microneedle, rGO, and membrane, the biosensor exhibited excellent linearity up to 10 mM lactate with a limit of detection of 2.04 μM, high sensitivity of 43.96 μA mM−1cm−2, a reaction time of 8 s and outstanding stability, selectivity, and repeatability. The feasibility of the microneedle is evaluated by using it to measure lactate concentrations in artificial ISF and human serum. The results demonstrate that the microneedle described here has great potential for use in real-time lactate monitoring for use in sports medicine and treatment.

From Basic Research on Supported-Metal Catalysts to their Practical Applications for Reduction of Food Waste

Abstract Supported metal catalysts are one of the most important heterogeneous catalysts, and they are widely used in chemical processes such as naphtha reforming, purification of exhaust gas from automobiles and so on. However, rational design of supported metal catalysts is still a target in heterogeneous catalysis. The author had a hypothesis that metal nanoparticles in ordered pores of zeolite or mesoporous silica may exhibit novel catalytic properties. Based on this idea, we used micropores of zeolites to accommodate metal carbonyl clusters, and then mesoporous silica to prepare metal nanoparticles. First, we studied ship-in-bottle synthesis of Rh carbonyl clusters in zeolite and its reactivity. Rh6(CO)16 was synthesized in NaY zeolite accompanied with formation of a mononuclear Rh(CO)2, which acted as a carrier of 13CO in 12CO-13CO exchange reaction. Then we worked on synthesis of platinum nanoparticles in mesoporous silica, and found that high activity in preferential oxidation of CO in hydrogen and in low-temperature oxidation of ethylene. The high catalytic performance in ethylene oxidation has led to practical application of platinum/silica catalysts for preservation of fruits and vegetables, resulting in reduction of food waste. This article describes the development process of this research.

Antioxidant Activity of Green Synthesized Platinum Nanoparticles by Using Tornabea scutellifera Extract

First time in this study Tornabea scutellifera extract were used for synthesis of Platinium nanoparticles (Pt NPs). The DPPH scavenging activity of T. scutellifera-based Pt NPs was determined and its usability as antioxidant activity was evaluated. With characterization tests, it was observed that Pt NPs were in spherical structure and had an average diameter of 88.7 nm. Functional groups that play a role in the synthesis were determined by FT-IR analysis with the peaks determined at 1623 cm-1, 1146 cm-1, 1042 cm-1, 987 cm-1, 625 cm-1 ve 558 cm-1. Elemental structure (presence of Pt) was revealed by EDX analysis. It was determined that T. scutellifera-based Pt NPs exhibited anti-oxidant activity against DPPH (184.06 µg/ml, R2=0.8727). It is thought that the study can be used in nanotechnology-related multidisciplinary studies.

Synthesis of Platinum Nanoparticles Supported on Fused Nanosized Carbon Spheres Derived from Sustainable Source for Application in a Hydrogen Generation Reaction

The dwindling supply of fossil fuels has prompted the search for an alternative energy source that could effectively replace them. Potential renewable energy sources such as solar, wind, tidal, and geothermal are all promising but each has its own drawbacks. Hydrogen gas on the other hand can be combusted to produce energy with only water as a byproduct and can be steadily generated via the aqueous media hydrolysis reaction of Sodium Borohydride (NaBH4). This study successfully synthesized fused carbon spheres derived from sugar and decorated them with platinum nanoparticles to form a novel composite material (PtFCS) for catalyzing this reaction. The platinum nanoparticles were produced by reducing chloroplatinic acid in a solution with sodium borohydride and using sodium citrate as a capping agent for the nanoparticles. Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to characterize and determine the size and shape of the Pt nanoparticles (PtNPs) and fused carbon spheres. TEM was able to determine the average size of the fused carbon spheres to be 200 nm and the average size for the PtNPs to be 2–3 nm. The PtFCS composite was tested for its ability to catalyze the hydrolysis of NaBH4 under various reaction conditions including various solution pH, various temperatures, and various dosages of sodium borohydride. The catalyst was found to perform the best under acidic solution conditions (pH 6), producing hydrogen at a rate of 0.0438 mL/mgcat·min. The catalyst was determined to have an activation energy of 53.0 kJ/mol and could be used multiple times in succession with no loss in the volume of hydrogen produced. This sugar-derived composite catalyst shows promise and could be implemented as a sustainable catalyst for the generation of hydrogen fuel.

The Kinetics of the Redox Reaction of Platinum(IV) Ions with Ascorbic Acid in the Presence of Oxygen

In this work, the kinetics of the redox reaction between platinum(IV) chloride complex ions and ascorbic acid is studied. The reduction process of Pt(IV) to Pt(II) ions was carried out at different reagent concentrations and environmental conditions, i.e., pH (2.2–5.1), temperature (20–40 °C), ionic strength (I = 0.00–0.40 M) and concentrations of chloride ions (0.00–0.40 M). The kinetic traces during the reduction process were registered using stopped-flow spectrophotometry. Based on the kinetic traces, the rate constants were determined, and the kinetic equations were proposed. It was shown that in the mild acidic medium (pH = 2.5), the reduction process of Pt(IV) to Pt(II) ions is more complex in the presence of oxygen dissolved in the aqueous solutions. For these processes, the values of the enthalpy and entropy of activation were determined. Moreover, the mechanism of the reduction of Pt(IV) to Pt(II) ions was proposed. The presented results give an overview of the process of the synthesis of platinum nanoparticles in the solution containing oxygen, in which the reduction process of Pt(IV) to Pt(II) ions is the first step.

Synthesis and Evaluation of Platinum Nanoparticles Using F. Carica Fruit Extract and Their Antimicrobial Activities

Abstract In this manuscript, a simple new method for the green synthesis of platinum nanoparticles (Pt NPs) utilizing F. carica Fig extract as reducing agent for antimicrobial activities was reported. Simultaneously, the microstructural and morphological features of the synthesized Pt NPs were thoroughly investigated. In particular, the attained Pt NPs exhibited spherical shape with diameter range of 5-30 nm and root mean square of 9.48 nm using Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM), respectively. Additionally, the final product (Pt NPs) was screened as antifungal and antibacterial agent against Candida and Aspergillus species as well as Gram-positive Staphyllococcus aureus and Gram-negative Acinetobacter species, respectively. Accordingly, the synthesized NPs demonstrated inhibition zones of 36 and 28 mm against fungal and bacterial species, respectively. The presented Pt NPs play an active role in both antifungal and antibacterial activities which indicates the presence of a well-regulated nano-materials system for biomedical application.

Stretchable Low-Impedance Conductor with Ag-Au-Pt Core-Shell-Shell Nanowires and in Situ Formed Pt Nanoparticles for Wearable and Implantable Device.

Mechanically soft metallic nanocomposites have gained much attention as a key material for intrinsically stretchable biointegrated devices. However, it has been challenging to develop a stretchable conductive nanocomposite with all the desired material characteristics including high conductivity, high stretchability, low cytotoxicity, and low impedance. Here, we present a material strategy for the stretchable conductive nanocomposite, particularly emphasizing low impedance, by combining silver-gold-platinum core-shell-shell nanowires and homogeneously dispersed in situ synthesized platinum nanoparticles (Pt NPs). The highly embossed structure of the outermost Pt shell, together with the intrinsic electrical property of Pt, contributes to minimizing the impedance. The gold-platinum double-layer sheath prevents leaching of cytotoxic Ag ions, thus improving biocompatibility. Homogeneously dispersed Pt NPs, synthesized in situ during fabrication of the nanocomposite, simultaneously enhance conductivity, reduce impedance, and improve stretchability by supporting the percolation network formation. This intrinsically stretchable nanocomposite conductor can be applied to wearable and implantable bioelectronics for recording biosignals and delivering electrical stimulations in vivo.

Surfactant- and Ligand-Free Synthesis of Platinum Nanoparticles in Aqueous Solution for Catalytic Applications

The synthesis of surfactant-free and organic ligand-free metallic nanoparticles in solution remains challenging due to the nanoparticles’ tendency to aggregate. Surfactant- and ligand-free nanoparticles are particularly desirable in catalytic applications as surfactants, and ligands can block access to the nanoparticles’ surfaces. In this contribution, platinum nanoparticles are synthesized in aqueous solution without surfactants or bound organic ligands. Pt is reduced by sodium borohydride, and the borohydride has a dual role of reducing agent and weakly interacting stabilizer. The 5.3 nm Pt nanoparticles are characterized using UV-visible spectroscopy and transmission electron microscopy. The Pt nanoparticles are then applied as catalysts in two different reactions: the redox reaction of hexacyanoferrate(III) and thiosulfate ions, and H2O2 decomposition. Catalytic activity is observed for both reactions, and the Pt nanoparticles show up to an order of magnitude greater activity over the most active catalysts reported in the literature for hexacyanoferrate(III)/thiosulfate redox reactions. It is hypothesized that this enhanced catalytic activity is due to the increased electron density that the surrounding borohydride ions give to the Pt nanoparticle surface, as well as the absence of surfactants or organic ligands blocking surface sites.

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation.

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption. Transmission electron microscopy (TEM) shows that small primary NPs with sizes of 2 nm to 5 nm are obtained in TAAILs and EG/TAAIL mixtures. The Pt-NPs feature excellent activity as electrocatalysts in the hydrogen evolution reaction (HER) under acidic conditions, with an overpotential at a current density of 10 mA cm-2 as low as 32 mV vs the reversible hydrogen electrode (RHE), which is significantly lower than the standard Pt/C 20% with 42 mV. Pt-NPs obtained in TAAILs also achieved quantitative conversion in the hydrosilylation reaction of phenylacetylene with triethylsilane after just 5 min at 200 °C.

An effective bio-inspired synthesis of platinum nanoparticles using Caulerpa sertularioides and investigating their antibacterial and antioxidant activities.

In this study, we report the synthesis of platinum nanoparticles (Cs-PtNPs) using an aqueous extract of Caulerpa sertularioides as a reducing agent. Cs-PtNPs were characterized by UV-Vis spectroscopy, fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), high-resolution transmission electron microscopy (HR-TEM) and dynamic light scattering (DLS) analysis. Cs-PtNPs are spherical with a particle size of 6-22nm. Cs-PtNPs have been shown to have highly effective antioxidant activities with 74% for DPPH, 63% for reducing power, and 59% for total antioxidant at 1mg/ml, and results were compared with standard L-ascorbic acid. Furthermore, the Cs-PtNPs demonstrated excellent antibacterial activity against the Gram-negative bacteria, Vibrio parahaemolyticus with the highest zone of inhibition (18mm) at 50µg/ml. Moreover, Artemia nauplii showed less toxicity when treated with Cs-PtNPs at 150µg/ml, indicating that the Cs-PtNPs are less toxic and environment friendly.

Inkjet-Assisted Electroformation of Magnetically Guidable Water Striders for Interfacial Microfluidic Manipulation.

Gerridae, colloquially called water striders, are a peculiar class of insects characterized by the extraordinary ability to walk on the surface of water bodies. Owing to this capacity, they constitute an ideal source of inspiration for designing untethered microdevices capable of navigating the interface between two fluids. Such steerable micrometric objects can be of great interest for various applications, ranging from the handling of floating objects to the remote control of microreactions and the manipulation of self-assembled monolayers. This paper describes the realization of artificial water striders via an inkjet-assisted electroforming approach. Inkjet deposition patterns the negative mask, which is subsequently filled with different layers of metals through electroforming. One of such layers is the magnetic alloy NiFe, which allows wireless propulsion of the striders by means of externally applied magnetic fields. The magnetic actuation tests prove good maneuverability at the water-air and silicone oil-air interfaces, with superior control over the speed and position of the devices. The surface of the devices is modified to tune its superficial energy in order to maximize buoyancy on these different combinations of fluids. A magnetic field-controlled strider manipulates a droplet and demonstrates collecting oil microdroplets and synthesizing platinum nanoparticles by chemical microreactions. Finally, the remotely operated microrobot could be employed in laboratories as a real avatar of chemists.