Bio-inspired synthesis of biologically and catalytically active silver chloride-anchored Palladium/Gold/Silver Trimetallic nanoparticles

BackgroundCandida species are opportunistic fungus that can cause serious infections, particularly in immunocompromised population. The number of fungal infections has increased steadily with Candida species being responsible for ˃ 70% of these instances, particularly in hospitalized patients with significant underlying conditions. Pharmacological resistance in Candida species and the advent of Candida auris have elevated candidiasis to a major public health concern. Candida auris is an emerging multidrug-resistant fungus that can cause catastrophic bloodstream infections and high fatality rates, particularly in hospitalized patients with major medical issues. Antifungal study of trimetallic nanoparticles (NPs) of various types have been studied as a therapy option for efficient and safe control of candidiasis. These NPs were highlighted for being environmentally friendly and sustainable synthetic preparative possibilities.ObjectiveThis work aimed to synthesize and characterize novel Cu-Zn-Fe trimetallic NPs and determine their in vitro antifungal activity and mechanism of antifungal action against Candida auris isolates.MethodsThe synthesis and characterization of Cu-Zn-Fe trimetallic NPs was done by standard methods. The antifungal capability of these NPs were determined by calculating minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) following CLSI recommended guidelines. Susceptibility on planktonic cells and biofilms was further confirmed by MuseTM cell count and viability assay and scanning electron microscopy (SEM) respectively. For insight antifungal mechanisms, apoptosis and cell cycle arrest were studied by exploring different apoptotic markers and MuseTM cell analyzer.ResultsCharacterizations by Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) determine the successful biosynthesis of Cu-Zn-Fe trimetallic NPs. Susceptibility assay confirmed the fungicidal activity of Cu-Zn-Fe NPs with MIC and MFC values of 12.5 and 25 μg/ml respectively. These results were further confirmed by viability assay reporting the cell viability of 45.5%, 13.5%, and 1.8% when C. auris cells were treated with 1/2 MIC, MIC, and 2MIC respectively. Cell cycle analysis revealed that 91.2% of healthy developing untreated control cells were in G0/G1 phase, whereas 5.2% and 3.7% of cells were in the S phase and G2/M phase, respectively. In contrast, NP-treated cells were observed to be arrested in S phase with 49.3% cells at 2MIC. To study the physiology of cell death caused by NPs, we investigated mitochondrial membrane potential (∆ψm), with live cells having stable (∆ψm) whereas treated cells showed loss of (∆ψm). Another important parameter of apoptosis in yeast cells is the release of cytochrome C from the mitochondria to the cytosol and NP-treated cells resulting in decreased mitochondrial cytochrome C and elevated cytosolic cytochrome C levels. Both results confirmed the potential test NPs in causing apoptotic cell death in C. auris.ConclusionThe trimetallic (Cu-Zn-Fe) nanoparticles displayed strong antifungal activity against C. auris, with a potential to arrest the cell cycle at S-phase, which could be linked to the DNA damage. Important yeast apoptotic markers suggested that the test NPs have a potential to cause apotosis in C. auris. All these findings suggest the potential of these trimetallic NPs to be taken to the next level of research in the development of novel antifungal medications.

采用化学共还原方法制备了聚乙烯吡咯烷酮（PVP）保护的Pt/Ni/Fe三金属纳米颗粒，对所合成的纳米颗粒进行了表征，研究了三金属纳米颗粒的化学组成对其催化NaBH 4 制氢的影响. 研究结果表明，Pt/Ni/Fe三金属纳米颗粒的平均粒径在2 nm左右，Pt/Ni/Fe三金属纳米颗粒催化活性高于Pt，Ni或Fe单金属纳米颗粒和Pt/Ni，Pt/Fe或Ni/Fe双金属纳米颗粒的催化活性，其中Pt 10 Ni 78.75 Fe 11.25 三金属纳米颗粒的催化活性最高，30 ℃时，其催化活性可达63.920×10 3 mol H 2 /（mol Pt ·h）. Pt/Ni/Fe三金属纳米溶胶催化剂具有很好的催化稳定性，10次重复催化实验后，该催化剂依然可以保持较高的催化活性. 该三金属纳米溶胶催化NaBH 4 水解反应的活化能为52 kJ/mol.

Revolution from monometallic to trimetallic nanoparticle composites, various synthesis methods and their applications: A review

Abstract: Biogenic metallic nanoparticles (NPs) produced from garlic and ginger have a wide range of applications in the pharmaceuticals, biotechnology and electronics industries. Despite many commercial NPs reported, NPs made from natural extracts are more affordable, straightforward and environmentally friendly than synthetic approaches. Biogenic metallic NPs derived from garlic and ginger have superior biocompatibility, better dispersion, higher stability, and stronger biological activities. This is due to the fact that garlic and ginger possess significant activities against multi-drug resisted pathogens and are in high demand, especially for the prevention of microbial diseases. This review placed a substantial emphasis on comparative investigations of the synthesis of mono-, bi-, and tri-metallic NPs with a variety of sizes and forms, as well as applications using materials like ginger and garlic. The benefits and drawbacks of mono-metallic, bi-metallic, and tri-metallic biogenic NPs produced from garlic and ginger are also comprehensively highlighted. Recent improvements have opened the way to site-specific targeting and drug delivery by these metallic NPs.

This paper describes how irradiation with light influences the preparation of Au-Ag-Hg trimetallic nanoparticles (NPs) from gold nanorods (AuNRs) in glycine solutions (pH 8.5-10.5). Silver, gold, and mercury ions were reduced by ascorbic acid and deposited on AuNRs to form Au-Ag-Hg trimetallic NPs of different sizes and shapes. In addition to the amounts of ascorbic acid, Au seeds, and glycine, others parameters such as pH, irradiation, and the concentrations of Ag, Au, and Hg ions are important for the preparation of these Au-Ag-Hg trimetallic NPs. Transmission electron and dark-field microscopy images indicated that irradiation with light induced the self-assembly of the thus-prepared Au-Ag-Hg trimetallic NPs, in addition to slightly affecting their shapes, but suggested no photoreduction effect during their formation. At pH 10.5, the Au-Ag-Hg trimetallic NPs possessed dumbbell- and millet-like shapes, having the sizes of 51 +/- 3 and 48 +/- 4 nm, respectively, when synthesized in the dark and under illumination, respectively. Time-evolution UV-Vis extinction spectroscopy and inductively coupled plasma mass spectrometry data obtained from solutions at various periods during the formation of the Au-Ag-Hg trimetallic NPs reveal that reduction of the Au and Ag ions occurred prior to reduction of the Hg ions. To the best of our knowledge, this study presents the first example of the light-induced self-assembly of Au-Ag-Hg trimetallic NPs in a liquid phase.

Stable structure optimization of Pt-X-Cu (X = Au, Ag, Pd and Rh) trimetallic nanoparticles

Hydrogen energy is considered a promising renewable energy source. In the hydrogen evolution reaction (HER), hydrogen binding energy (HBE) plays a critical role in determining the catalytic performance. Platinum-group metals (PGMs) exhibit optimal HBE, which positions them at the top of the HER volcano plot, highlighting their superior catalytic activity. However, the high cost and limited availability of PGMs restrict their widespread application. To address this challenge, the incorporation of non-noble metals into catalysts is a key strategy to reduce PGM usage and lower costs.In this work, we employed the Sabatier principle to design trimetallic alloy catalysts with intermediate HBE by selecting a PGM (Ir, Pt, Pd, Ru, or Rh), molybdenum (with a strong HBE), and copper (with a weak HBE). The goal was to develop catalysts with comparable or superior HER performance to pure PGMs while reducing costs. Trimetallic alloy nanoparticles were synthesized on a Vulcan carbon substrate using a high-temperature reduction method. The catalysts were characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD), and the reduction mechanism was further investigated using hydrogen temperature-programmed reduction (H2-TPR). We observed that the presence of PGMs catalyzed the reduction of more difficult-to-reduce Mo and Cu metal precursors via an autocatalytic reduction mechanism at temperatures below 300 °C. Among the synthesized catalysts, the Ir-Mo-Cu alloy exhibited the most stable structure and phase, consisting primarily of solid-solution Ir-Mo-Cu trimetallic nanoparticles, with some Ir-Cu alloy surfaces modified by randomly distributed Mo clusters. Synchrotron X-ray absorption spectroscopy (XAS) of the Ir-Mo-Cu alloy confirmed the presence of Ir-Mo-Cu and Mo-Mo coordination, supporting the HRTEM and XRD results.In electrocatalytic testing, we optimized the ratio of non-noble metals in the Ir-Mo-Cu alloy to evaluate its HER performance. The results demonstrated that Ir0.2Mo0.4Cu0.4 achieved the highest mass activity (6.4 A/mgPGM), outperforming commercial Pt/C (0.64 A/mgPGM) by a factor of 10. Furthermore, density functional theory (DFT) calculations revealed that the Ir-Mo-Cu trimetallic nanoparticles exhibited a suitable hydrogen adsorption free energy (ΔGH*), close to 0, indicating that their hydrogen adsorption capability is neither too strong nor too weak. These findings confirm the effectiveness of the catalyst design based on the Sabatier principle. We anticipate that this methodology can be extended to the design of catalysts for other elements and catalytic reactions.

Uniform, Scalable, High-Temperature Microwave Shock for Nanoparticle Synthesis through Defect Engineering

Alloy nanoparticles exhibit multifunctional properties different from monometallic nanoparticles. Especially, when a third metal is introduced into bimetallic nanoparticles system to form trimetallic nanoparticles, their chemical activities will be further improved. As the catalytic reaction of nanoparticles usually takes place on surfaces, and the activity and stability are closely related to their structures, therefore the research on the stable structure is crucial for understanding their catalytic activities. In addition, the electrochemically synthesized tetrahexahedral nanoparticles bound with highindex facets may exhibit greatly enhanced catalytic activity because of their large density of low coordination sites at the surface. Based on the above reasons, this paper carries out the investigation on the stable structures of tetrahexahedral Au-Cu-Pt trimetallic nanoparticles by using an improved genetic algorithm and the quantum-corrected Sutton-Chen (Q-SC) type many-body potentials. To avoid the genetic algorithm being trapped into premature convergence, two improvement strategies are developed. On the one hand, an atom coordinate ranking operation, which is implemented according to the atomic distance from the core, is proposed for reducing the probability of individual loss. On the other hand, an alternating bit means is introduced into the crossover operation to keep the atomic composition ratio unchanged. Moreover, the performance of genetic algorithm and the influence of original configuration on the stable structures of Au- Cu-Pt trimetallic nanoparticles with different sizes and different compositions also have been investigated. One stochastic distribution structure and three core-shell distribution structures of Au@CuPt, Cu@AuPt and Pt@AuCu are adopted as the initial structures, respectively. Eleven optimization trials on Au-Cu-Pt trimetallic nanoparticles in Au-Cu-Pt system with Au : Cu : Pt of 0:343 : 0:343 : 0:314 with 443 atoms are used to verify that the different original structures should have no effect on the final stable structure. Furthermore, 30 random trails on Au-Cu-Pt trimetallic nanoparticles at Au : Cu : Pt of 0:316 : 0:316 : 0:368 with 443 atoms are conducted to prove that the genetic algorithm can obtain robust results with small standard deviation. Finally, the segregation analysis results show that: In Au-Cu-Pt trimetallic nanoparticles, Au and Cu atoms prefer to aggregate on the surface while Pt atoms are preferential to locate in the core. Furthermore, Cu atoms exhibit stronger surface segregation than Au atoms. For small Au or Cu concentration, Au and Cu atoms would display the maximum segregation. They begin to compete during aggregation, and the Cu atoms have a strong tendency for surface segregation when the number of Au and Cu atoms is bigger than the total number of surface atoms. With increasing number of Au and Cu atoms over those on the surface and sub-surface, Au atoms would display a strong surface segregation than Cu atoms. Additionally, Cu atoms will mix with Pt atoms in the inner layers over the sub-surface after occupying the surface. The distribution of surface atoms has been further examined by the analyses of coordination number: the Cu atoms tend to occupy the vertices, edges and kinks, while the Au atoms preferentially segregate to the flattened surface. This study provides a perspective on structural features and segregation behavior of trimetallic nanoparticles.

CuPt/Ag trimetallic alloy nanoparticles (NPs) were synthesized by co-sputtering onto liquid polyethylene glycol (PEG), using a CuPt alloy target and an Ag target.

We report synthesis of silver nanoparticles, bimetallic (Al2O3@Ag) nanoparticles and trimetallic (Al2O3@AgAu) nanoparticles by nanosecond pulse laser ablation (PLA) in deionized water. Two-step laser ablation methodologies were adopted for the synthesis of bi- and tri-metallic nanoparticles. In this method a silver or gold target was ablated in colloidal solution of γ-alumina nanoparticles prepared by PLA. The TEM image analysis of bimetallic and trimetallic particles reveals deposition of fine silver particles and Ag-Au alloy particles, respectively, on large alumina particles. The laser generated nanoparticles were tested for catalytic reduction of 4-nitrophenol to 4-aminophenol and showed excellent catalytic behaviour. The catalytic rate was greatly improved by incorporation of additional metal in silver nanoparticles. The catalytic efficiency of trimetallic Al2O3@AgAu for reduction of 4-nitrophenol to 4-aminophenol was remarkably enhanced and the catalytic reaction was completed in just 5 sec. Even at very low concentration, both Al2O3@Ag nanoparticles and Al2O3@AgAu nanoparticles showed improved rate of catalytic reduction than monometallic silver nanoparticles. Our results demonstrate that alumina particles in the solution not only provide the active sites for particle dispersion but also improve the catalytic activity.

Nanoparticles are materials whose size is less than 100 nm. Because of their distinctive physical and chemical characteristics, nanoparticles have drawn considerable interest in a variety of fields. Biosynthesis of nanoparticles is a green and environmentally friendly technology, which requires fewer chemical reagents, precursors, and catalysts. There are various types of nanomaterials, out of which trimetallic nanoparticles are receiving considerable interest in recent years. Trimetallic nanoparticles possess unique catalytic, biomedical, antimicrobial, active food packaging, and sensing applications as compared to monometallic or bimetallic nanoparticles. Trimetallic nanoparticles are currently synthesized by various methods such as chemical reduction, microwave-assisted, thermal, precipitation, and so on. However, most of these chemical and physical methods are expensive and toxic to the environment. Biological synthesis is one of the promising methods, which includes the use of bacteria, plants, fungi, algae, waste biomass, etc., as reducing agents. Secondary metabolites present in the biological agents act as capping and reducing agents. Green trimetallic nanoparticles can be used for different applications such as anticancer, antibacterial, antifungal, catalytic activity, etc. This review provides an overview of the synthesis of trimetallic nanoparticles using biological agents, and their applications in different areas such as anticancer, antimicrobial activity, drug delivery, catalytic activity, etc. Finally, current challenges, future prospects, and conclusions are highlighted.

Polymer‐protected metal nanoparticles (NPs) are recognized as a type of complex between a polymer and metal NPs, since the metal NPs are stabilized by coordination to the polymer. Thus, they can work as an effective catalyst in a dispersed state due to their high surface area‐to‐volume ratio and high stability by protection with poly(N‐vinyl‐2‐pyrrolidone) (PVP). In this study, colloidal dispersions of PVP‐protected and Au‐containing bi‐ and trimetallic NPs were prepared and applied to the catalyst for the aerobic oxidation of glucose into gluconic acid in an alkaline solution. The AuAg and AuPt bimetallic NPs were more active than the Au NPs although the Ag and Pt NPs were less active than the Au NPs. The AuAgPt (Au/Ag/Pt = 7/2/1) trimetallic NPs were the most active catalyst for the same reaction. The high activity can be explained by electronic charge transfer from the Ag or Pt to the Au.

Fe/La/Zn nanocomposite with graphene oxide for photodegradation of phenylhydrazine

This paper reports the findings of an investigation of the correlations between the catalytic activity for aerobic glucose oxidation and the composition of Au/Pt/Rh trimetallic nanoparticles (TNPs) with average diameters of less than 2.0 nm prepared by rapid injection of NaBH4. The prepared TNPs were characterized by UV–Vis, TEM, and HR-TEM. The catalytic activity of the alloy-structured TNPs for aerobic glucose oxidation is several times higher than that of Au monometallic nanoparticles with nearly the same particle size. The catalytic activities of the TNP catalysts were dependent not only on the composition, but also on the electronic structure. The high catalytic activities of the Au/Pt/Rh TNPs can be ascribed to the formed negative-charged Au atoms due to electron donation of Rh neighboring atoms acting as catalytically active sites for aerobic glucose oxidation.