A Photodynamic and Photochemotherapeutic Platinum-Iridium Charge-Transfer Conjugate for Anticancer Therapy.

The novel hetero-dinuclear complex trans,trans,trans-[PtIV(py)2(N3)2(OH)(µ-OOCCH2CH2CONHCH2-bpyMe)IrIII(ppy)2]Cl (Pt-Ir), exhibits charge transfer between the acceptor photochemotherapeutic Pt(IV) (Pt-OH) and donor photodynamic Ir(III) (Ir-NH2) fragments. It is stable in the dark, but undergoes photodecomposition more rapidly than the Pt(IV) parent complex (Pt-OH) to generate Pt(II) species, an azidyl radical and 1O2. The Ir(III)* excited state, formed after irradiation, can oxidise NADH to NAD⋅ radicals and NAD+. Pt-Ir is highly photocytotoxic towards cancer cells with a high photocytotoxicity index upon irradiation with blue light (465 nm, 4.8 mW/cm2), even with short light-exposure times (10-60 min). In contrast, the mononuclear Pt-OH and Ir-NH2 subunits and their simple mixture are much less potent. Cellular Pt accumulation was higher for Pt-Ir compared to Pt-OH. Irradiation of Pt-Ir in cancer cells damages nuclei and releases chromosomes. Synchrotron-XRF revealed ca. 4× higher levels of intracellular platinum compared to iridium in Pt-Ir treated cells under dark conditions. Luminescent Pt-Ir distributes over the whole cell and generates ROS and 1O2 within 1 h of irradiation. Iridium localises strongly in small compartments, suggestive of complex cleavage and excretion via recycling vesicles (e.g. lysosomes). The combination of PDT and PACT motifs in one molecule, provides Pt-Ir with a novel strategy for multimodal phototherapy.

A Pt1Pd Single-Atom Alloy Nanozyme with Boosted Enzyme-Like Activity for Efficient Photo-Mediated Tumor Therapy.

Single-atom nanozymes (SAzymes) are emerging natural enzyme mimics and have attracted much attention in the biomedical field. SAzymes with Metal─Nx sites designed on carbon matrixes are currently the mainstream in research. It is of great significance to further expand the types of SAzymes to enrich the nanozyme library. Single-atom alloys (SAAs) are a material in which single-atom metal sites are dispersed onto another active metal matrix, and currently, there is limited research on their enzyme-like catalytic performance. In this work, a biodegradable Pt1Pd SAA is fabricated via a simple galvanic replacement strategy, and for the first time reveals its intrinsic enzyme-like catalytic performance including catalase-, oxidase-, and peroxidase-like activities, as well as its photodynamic effect. Experimental characterizations demonstrate that the introduction of single-atom Pt sites contributes to enhancing the affinity of Pt1Pd single-atom alloy nanozyme (SAAzyme) toward substrates, thus exhibiting boosted catalytic efficiency. In vitro and in vivo experiments demonstrate that Pt1Pd SAAzyme exhibits a photo-controlled therapeutic effect, with a tumor inhibition rate of up to 100%. This work provides vital guidance for opening the research direction of SAAs in enzyme-like catalysis.

Chemodynamic/Photothermal Synergistic Cancer Immunotherapy Based on Yeast Microcapsule-Derived Au/Pt Nanoparticles.

In recent years, microbiota-based tumor immunotherapy has become a hotspot in cancer research. However, the use of microorganisms alone to activate the immune response for antitumor therapy was unsatisfactory. In this study, we biosynthesized gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) based on yeast microcapsules to activate the immune response for antitumor treatment in synergy with chemodynamic therapy (CDT) and photothermal therapy (PTT). We generated AuNPs and PtNPs on yeast microcapsules (YAP) and fabricated nanoscale particles (Bre-YAP) by ultrasonic fragmentation and differential centrifugation. Bre-YAP retained the glucan component of yeast as an adjuvant; in the meantime, these two kinds of metal nanoparticles contained were excellent CDT and PTT mediators. By inspection, they could reach a high level of distribution in tumors and tumor-draining lymph nodes (TDLNs). Under the laser irradiation of tumors, this immunological nanomaterial significantly remodeled the microenvironments of tumors and TDLNs. The primary tumors were effectively inhibited or even eradicated, and the overall survival of mice was significantly improved as well. Therefore, yeast microcapsule-based Bre-YAP with immune properties could be used as an effective cancer treatment modality.

Antitumor potential of platinum(II) complexes of selenium donor ligands.

Platinum(II) coordination compounds are widely applied in clinics as anticancer drugs. In this review, we provide a summary of the reports on cytotoxic properties of platinum(II) complexes of selenium donor ligands along with a brief description of their structural features. It has been observed that the platinum(II) complexes of selenones and selenoethers display reasonable antitumor properties and in some cases their cytotoxic activity is greater than cisplatin. The complexes containing NH3 ligands along with selenones were found to exhibit better cytotoxicity compared to the binary Pt-selenone complexes. The mechanistic insights showed that these complexes exert antitumor activity through reactive oxygen species (ROS) generation and induction of apoptosis. The platinum-selenoether coordination compounds can self-assemble into spherical aggregates capable of self-delivery. The self-assembled Pt-selenium aggregates induce cell apoptosis via ROS, which leads to high selectivity between cancer cells and normal cells in cytotoxicity assays.

Platin-C containing nanoparticles: a recipe for the delivery of curcumin-cisplatin combination chemotherapeutics to mitochondria.

The success story of cisplatin spans over six decades now and yet it continues to be the key player in most chemotherapeutic regimens. Numerous efforts have been made to improve its efficacy, address its shortcomings, and overcome drug resistance. One such strategy is to develop new platinum(IV)-based prodrugs with functionally active ligands to deliver combination therapeutics. This strategy not only enables the drug candidate to access multiple drug targets but also enhances the kinetic inertness of platinum complexes and thereby ensures greater accumulation of active drugs at the target site. We report the synthesis of Platin-C, a platinum(IV)-based cisplatin prodrug tethered to the active component of ancient herbal medicine, curcumin, as one of the axial ligands. This combination complex showed improved chemotherapeutic efficacy in cisplatin resistant A2780/CP70 cell lines compared with the individual components. An amine-terminated biodegradable polymer was suitably functionalized with the triphenylphosphonium (TPP) cation to obtain a mitochondria-directed drug delivery platform. Quantification of Platin-C loading into these NPs using complementary techniques employing curcumin optical properties in high-performance liquid chromatography and platinum-based inductively coupled plasma mass spectrometry evidenced efficacious payload incorporation resulting in functional activities of both the components. Stability studies for a period of one week indicated that the NPs remain stable, enabling substantial loading and controlled release of the prodrug. The targeting nanoparticle (NP) platform was utilized to deliver Platin-C primarily in the mitochondrial network of cancer cells as monitored using confocal microscopy employing the green fluorescence of the curcumin pendant. Our studies showed that amine terminated NPs were relatively less efficient in their ability to target mitochondria despite being positively charged. This re-validated the importance of lipophilic positively charged TPP surface functionalities to successfully target cellular mitochondria. We validated the capabilities of Platin-C and its mitochondria-targeting nanoparticles towards inflicting mitochondria-directed activity in cisplatin-sensitive and cisplatin-resistant cell lines. Furthermore, our studies also demonstrated the effectiveness of Platin-C incorporated targeting NPs in attenuating cellular inflammatory markers by utilizing the curcumin component. This study advances our understanding of the cisplatin prodrug approach to combine chemotherapeutic and inflammatory effects in accessing combinatory pathways.

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 6-22 nm. 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 1 mg/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 (18 mm) at 50 µg/ml. Moreover, Artemia nauplii showed less toxicity when treated with Cs-PtNPs at 150 µg/ml, indicating that the Cs-PtNPs are less toxic and environment friendly.

Strongly Improving the Sensitivity of Phosphorescence-Based Optical Oxygen Sensors by Exploiting Nano-Porous Substrates.

Sensitivity is one of the crucial factors in determining the quality of a fluorescence/phosphorescence-based gas sensor, and is estimated from the measurement of responses (I0/I, where I0 and I refer to the measured optical intensity of a sensor in absence and presence of analyte molecules) at various concentrations of analytes. In this work, we demonstrate phosphorescence-based optical oxygen sensors fabricated on highly porous anodic aluminum oxide (AAO) membranes showing dramatically high response. These sensors exploit the enormous surface area of the AAO to facilitate the effective interaction between the sensing molecules and the analytes. We spin-coat an AAO membrane (200 nm pore diameter) with a platinum-based oxygen sensing porphyrin dye, platinum(II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP), to fabricate a sensor exhibiting I0/I ~400 at 100% oxygen atmosphere. To address the generality of the AAO membrane, we fabricate a separate sensor with another porphyrin dye, platinum octaethylporphyrin (PtOEP), which exhibits an even higher I0/I of ~500. Both of these sensors offer the highest responses as an optical oxygen sensor hitherto reported. SEM and EDS analysis are performed to realize the effect of the increased surface area of the AAO membrane on the enhanced sensitivity.

Silicon nanowires decorated with platinum nanoparticles were applied for photothermal-enhanced sonodynamic therapy.

Sonodynamic therapy (SDT) triggered by ultrasound (US) can overcome pivotal limitations of photo-therapy owing to its high depth-penetration and low phototoxicity. However, there is still a need to develop more efficient sonosensitizes to enhance the therapy efficiency. Methods: In this study, Pt nanoparticles (Pt NPs) are reduced on silicon nanowires (SiNWs) by in situ reduction to prepare Si-Pt nanocomposites (Si-Pt NCs). Results: Si-Pt NCs can produce reactive oxygen radicals (ROS) under ultrasound (US) irradiation, which have sonodynamic therapy (SDT) effect. Meanwhile, Si-Pt NCs can convert excess hydrogen peroxide (H2O2) into ROS in the tumor microenvironment, which endow strong chemodynamic therapy (CDT) effect. Taking the advantages of the mesoporous structure of SiNWs, the SDT and CDT effects of Si-Pt NCs are stronger than those of the pure Pt NPs and SiNWs. Besides, the mild photothermal effect of Si-Pt NCs further improves the SDT&CDT activity and realizes the combined cancer therapy. Conclusion: The developed Si-Pt NCs with the ability of photothermal enhanced SDT/CDT combined therapy play a momentous role in the novel cancer treatment.

Structural determination of arginine-linked cisplatin complexes via IRMPD action spectroscopy: arginine binds to platinum via NO- binding mode.

Cisplatin, (NH3)2PtCl2, has been known as a successful metal-based anticancer drug for more than half a century. Its analogue, Argplatin, arginine-linked cisplatin, (Arg)PtCl2, is being investigated because it exhibits reactivity towards DNA and RNA that differs from that of cisplatin. In order to understand the basis for its altered reactivity, the deprotonated and sodium cationized forms of Argplatin, [(Arg-H)PtCl2]- and [(Arg)PtCl2 + Na]+, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy in the IR fingerprint and hydrogen-stretching regions. Complementary electronic structure calculations are performed using density functional theory approaches to characterize the stable structures of these complexes and to predict their infrared spectra. Comparison of the theoretical IR spectra predicted for various stable conformations of these Argplatin complexes to their measured IRMPD spectra enables determination of the binding mode(s) of Arg to the Pt metal center to be identified. Arginine is found to bind to Pt in a bidentate fashion to the backbone amino nitrogen and carboxylate oxygen atoms in both the [(Arg-H)PtCl2]- and [(Arg)PtCl2 + Na]+ complexes, the NO- binding mode. The neutral side chain of Arg also interacts with the Pt center to achieve additional stabilization in the [(Arg-H)PtCl2]- complex. In contrast, Na+ binds to both chlorido ligands in the [(Arg)PtCl2 + Na]+ complex and the protonated side chain of Arg is stabilized via hydrogen-bonding interactions with the carboxylate moiety. These findings are consistent with condensed-phase results, indicating that the NO- binding mode of arginine to Pt is preserved in the electrospray ionization process even under variable pH and ionic strength.

Gold-Platinum Nanodots with High-Peroxidase-like Activity and Photothermal Conversion Efficiency for Antibacterial Therapy.

Combined therapeutic strategies for bacterial infection have attracted worldwide attention owing to their faster and more effective therapy with fewer side effects compared with monotherapy. In this work, gold-platinum nanodots (AuPtNDs) are simply and quickly synthesized by a one-step method. They not only exhibit powerful peroxidase-like activity but also confer a higher affinity for hydrogen peroxide (H2O2), which is 3.4 times that of horseradish peroxidase. Under 808 nm laser irradiation, AuPtNDs also have excellent photothermal conversion efficiency (50.53%) and strong photothermal stability. Excitingly, they can combat bacterial infection through the combination of chemodynamic and photothermal therapy. In vitro antibacterial results show that the combined antibacterial strategy has a broad-spectrum antibacterial property against both Escherichia coli (Gram negative, 97.1%) and Staphylococcus aureus (Gram positive, 99.3%). Animal experiments further show that nanodots can effectively promote the healing of bacterial infection wounds. In addition, owing to good biocompatibility and low toxicity, they are hardly traceable in the main organs of mice, which indicates that they can be well excreted through metabolism. These results reveal the application potential of AuPtNDs as a simple and magic multifunctional nanoparticle in antibacterial therapy and open up new applications for clinical anti-infective therapy in the near future.

Anisotropic Truncated Octahedral Au with Pt Deposition on Arris for Localized Surface Plasmon Resonance-Enhanced Photothermal and Photodynamic Therapy of Osteosarcoma.

The multifunctional combined nanoplatform has a wide application prospect in the synergistic treatment of cancer. Nevertheless, the traditional treatment of phototherapy is limited by the catalytic nanomaterial itself, so the effect is not satisfactory. Here, the arris of the anisotropic truncated octahedral Au (TOh Au) was coated with noble metal Pt to form a spatial separation structure, which enhanced the local surface plasmonic resonance and thus boosted the photocatalytic effect. In this system, the highly efficient photocatalysis provides a strong guarantee for oncotherapy. On the one hand, the structure of arris deposition adequately improves the efficiency of photothermal conversion, which substantially improves the effectiveness of photothermal therapy. On the other hand, in situ oxygen production of Pt ameliorates tumor hypoxia, and through the O2 self-production and sales mode, the growth and development of tumor were inhibited. Meanwhile, under the enhanced photocatalysis, more O2 were produced, which greatly evolved the treatment effect of photodynamic therapy. In the end, the addition of hyaluronic acid can specifically target osteosarcoma cells while improving the retention time and biocompatibility of the material in the body. Thus, the nanocomposite shows superexcellent synergistic enhancement of photothermal conversion efficiency and photodynamic capability in vitro and in vivo, which provides a potential possibility for osteosarcoma cure.

Shuttle-Shape Carrier-Free Platinum-Coordinated Nanoreactors with O2 Self-Supply and ROS Augment for Enhanced Phototherapy of Hypoxic Tumor.

The synergistic nanotheranostics of reactive oxygen species (ROS) augment or phototherapy has been a promising method within synergistic oncotherapy. However, it is still hindered by sophisticated design and fabrication, lack of a multimodal synergistic effect, and hypoxia-associated poor photodynamic therapy (PDT) efficacy. Herein, a kind of porous shuttle-shape platinum (IV) methylene blue (Mb) coordination polymer nanotheranostics-loaded 10-hydroxycamptothecin (CPT) is fabricated to address the abovementioned limitations. Our nanoreactors possess spatiotemporally controlled O2 self-supply, self-sufficient singlet oxygen (1O2), and outstanding photothermal effect. Once they are taken up by tumor cells, nanoreactors as a cascade catalyst can efficiently catalyze degradation of the endogenous hydrogen peroxide (H2O2) into O2 to alleviate tumor hypoxia. The production of O2 can ensure enhanced PDT. Subsequently, under both stimuli of external red light irradiation and internal lysosomal acidity, nanoreactors can achieve the on-demand release of CPT to augment in situ mitochondrial ROS and highly efficient tumor ablation via phototherapy. Moreover, under the guidance of near-infrared (NIR) fluorescent imaging, our nanoreactors exhibit strongly synergistic potency for treatment of hypoxic tumors while reducing damages against normal tissues and organs. Collectively, shuttle-shape platinum-coordinated nanoreactors with augmented ROS capacity and enhanced phototherapy efficiency can be regarded as a novel tumor theranostic agent and further promote the research of synergistic oncotherapy.

Mediator-Enabled Electrocatalysis with Ligandless Copper for Anaerobic Chan-Lam Coupling Reactions.

Simple copper salts serve as catalysts to effect C-X bond-forming reactions in some of the most utilized transformations in synthesis, including the oxidative coupling of aryl boronic acids and amines. However, these Chan-Lam coupling reactions have historically relied on chemical oxidants that limit their applicability beyond small-scale synthesis. Despite the success of replacing strong chemical oxidants with electrochemistry for a variety of metal-catalyzed processes, electrooxidative reactions with ligandless copper catalysts are plagued by slow electron-transfer kinetics, irreversible copper plating, and competitive substrate oxidation. Herein, we report the implementation of substoichiometric quantities of redox mediators to address limitations to Cu-catalyzed electrosynthesis. Mechanistic studies reveal that mediators serve multiple roles by (i) rapidly oxidizing low-valent Cu intermediates, (ii) stripping Cu metal from the cathode to regenerate the catalyst and reveal the active Pt surface for proton reduction, and (iii) providing anodic overcharge protection to prevent substrate oxidation. This strategy is applied to Chan-Lam coupling of aryl-, heteroaryl-, and alkylamines with arylboronic acids in the absence of chemical oxidants. Couplings under these electrochemical conditions occur with higher yields and shorter reaction times than conventional reactions in air and provide complementary substrate reactivity.

Electrochemical flow injection analysis for the rapid determination of reducing sugars in potatoes.

Non-enzymatic electrochemical sensors for the monitoring of reducing sugars in foods has great potential as a rapid in-situ detection method. This development involved the assembly of a nanoporous platinum structure on a screen-printed carbon electrode (SPCE). The modified electrode was then employed as an amperometric sensing element in a flow injection analysis (FIA) manifold. The system was successfully applied to the rapid detection of reducing sugars in potatoes, without the need for sample preparation. Optimal signals were achieved in phosphate buffer (pH 7.4) at a flow rate of 0.5 mL min-1 and an applied potential of 0.6 V. Experimental results demonstrated the sensor's long-term stability and high selectivity for reducing sugars. This method provides high sample throughput due to a rapid response time of less than five seconds. Reducing sugar values determined were in good agreement with those recorded using a commercially available enzymatic assay kit.

Novel Cells-Based Electrochemical Sensor for Investigating the Interactions of Cancer Cells with Molecules and Screening Multitarget Anticancer Drugs.

A novel, effective, and label-free electrochemical sensor was constructed for investigating the interactions between cancer cells and molecules, based on targeted cancer cells immobilized on a bilayer architecture of N-doped graphene-Pt nanoparticles-chitosan (NGR-Pt-CS) and polyaniline (PANI). The interactions between folic acid (FA, positive control) and dimethyl sulfoxide (DMSO, negative control) and the choice of targeted cells, HepG2 and A549 cells, were investigated by measuring the current change of the sensor to [Fe(CN)6]3-/4- before and after interactions, and the binding constants were calculated to be 1.37 × 105 and 1.92 × 105 M-1 by sensing kinetics. Furthermore, 18 main components from Aidi injection (ADI) were studied to screen compounds that have interactions with different targeted cancer cells including HepG2 and A549 cells. The potential target groups of the interactions between screened active compounds and targeted cancer cells were analyzed through computer-aided molecular docking. In this sensing system, molecules did not require electrochemical activity, and different targeted cancer cells could be immobilized on the modified electrode surface, truly reflecting the categories and numbers of targets. Additionally, the proposed sensor specifically circumvented the current paradigm in most cells-based electrochemical sensors for screening drugs, in which the changes in cell behavior induced by drugs are monitored. This study provided a novel, simple, and generally applicable method for exploring the interaction of molecules with cancer cells and screening multitarget drugs.

Nanozyme-Incorporated Biodegradable Bismuth Mesoporous Radiosensitizer for Tumor Microenvironment-Modulated Hypoxic Tumor Thermoradiotherapy.

Solid tumors inevitably develop radioresistance due to low oxygen partial pressure in the tumor microenvironment. Despite numerous attempts, there are still few effective ways to avoid the hypoxia-induced poor radiotherapeutic effect. To overcome this problem, platinum (Pt) nanodots were fabricated into a mesoporous bismuth (Bi)-based nanomaterial to construct a biodegradable nanocomposite BiPt-folic acid-modified amphiphilic polyethylene glycol (PFA). BiPt-PFA could act as a radiosensitizer to enhance the absorption of X-rays at the tumor site and simultaneously trigger response behaviors related to the tumor microenvironment due to the enrichment of materials in the tumor area. During this process, the Bi-based component consumed glutathione via coordination, thus altering the oxidative stress balance, while Pt nanoparticles catalyzed the decomposition of hydrogen peroxide to generate oxygen, thereby relieving tumor hypoxia. Both Pt and Bi thus co-modulated the tumor microenvironment to improve the radiotherapeutic effect. In addition, Pt dots in BiPt-PFA had strong near-infrared absorption ability and created an intensive photothermal therapeutic effect. Modulation of the tumor microenvironment could thus improve the therapeutic effect in hypoxic tumors by a combination of photothermal therapy and enhanced radiotherapy. BiPt-PFA, as a biodegradable nanocomposite, may thus modulate the tumor microenvironment to enhance the hypoxic tumor therapeutic effect by thermoradiotherapy.

Carbon Nanohorns/Pt Nanoparticles/DNA Nanoplatform for Intracellular Zn2+ Imaging and Enhanced Cooperative Phototherapy of Cancer Cells.

Superfluous zinc ion (Zn2+) in living cells has been identified as a potential tumor biomarker for early cancer diagnosis and cancer progression monitoring. In this paper, we developed a novel carbon nanohorns/Pt nanoparticles/DNA (CNHs/Pt NPs/DNA) nanoplatform based on the clamped hybridization chain reaction (c-HCR) process for intracellular Zn2+ imaging and enhanced cooperative phototherapy of cancer cells. Cross-shaped DNAzyme (c-DNAzyme), hairpin DNA1, hairpin DNA2, and aptamer DNA were adsorbed onto the surfaces of CNHs/Pt NPs, and the fluorescence of carboxytetramethyl-rhodamine was also quenched. After entering the living cells, the c-DNAzyme was cleaved to output trigger DNA in the existence of intracellular Zn2+ and initiate the c-HCR process for fluorescence amplification. Compared with the single HCR process triggered by a single DNAzyme, the c-HCR process could further improve the amplification efficiency and sensitivity. In addition, such a nanoprobe possesses a catalysis-enhanced photodynamic effect by Pt NP generation of oxygen in a tumor microenvironment and increases the photothermal effect by loading of Pt NPs on CNHs, indicating that this is a promising biological method for cancer diagnosis and cancer cell therapy.

Oxidation of Dichloromethane over Au, Pt, and Pt-Au Containing Catalysts Supported on γ-Al2O3 and CeO2-Al2O3.

Au, Pt, and Pt-Au catalysts supported on Al2O3 and CeO2-Al2O3 were studied in the oxidation of dichloromethane (DCM, CH2Cl2). High DCM oxidation activities and HCl selectivities were seen with all the catalysts. With the addition of Au, remarkably lower light-off temperatures were observed as they were reduced by 70 and 85 degrees with the Al2O3-supported and by 35 and 40 degrees with the CeO2-Al2O3-supported catalysts. Excellent HCl selectivities close to 100% were achieved with the Au/Al2O3 and Pt-Au/Al2O3 catalysts. The addition of ceria on alumina decreased the total acidity of these catalysts, resulting in lower performance. The 100-h stability test showed that the Pt-Au/Al2O3 catalyst was active and durable, but the selectivity towards the total oxidation products needs improvement. The results suggest that, with the Au-containing Al2O3-supported catalysts, DCM decomposition mainly occurs via direct DCM hydrolysis into formaldehyde and HCl followed by the oxidation of formaldehyde into CO and CO2.

Platinum Nanoparticles: Green Synthesis and Biomedical Applications.

Platinum nanoparticles (PtNPs) have superior physicochemical properties and great potential in biomedical applications. Eco-friendly and economic approaches for the synthesis of PtNPs have been developed to overcome the shortcomings of the traditional physical and chemical methods. Various biogenic entities have been utilized in the green synthesis of PtNPs, including mainly plant extracts, algae, fungi bacteria, and their biomedical effects were assessed. Other biological derivatives have been used in the synthesis of PtNPs such as egg yolk, sheep milk, honey, and bovine serum albumin protein. The green approaches for the synthesis of PtNPs have reduced the reaction time, the energy required, and offered ambient conditions of fabrication. This review highlights the state-of-the-art methods used for green synthesis of PtNPs, synthesis parameters, and their reported biomedical applications.

Biologically synthesized of Au/Pt/ZnO nanoparticles using Arctium lappa extract and cytotoxic activity against leukemia.

The main objective of this work was to assess the cytotoxic activity of Au/Pt/ZnO nanoparticles synthesized using Arctium lappa extract against leukemia. The Au/Pt/ZnO nanoparticles obtained as a result of biological synthesis were characterized by UV-Vis, Scanning (SEM) and Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Atomic Force Microscopy (AFM). The applied methods showed that the size of nanoparticles ranged from 10 to 40 nm. This work also assessed the cytotoxicity of Au/Pt/ZnO nanoparticles by means of MTT assay, and analyzed apoptosis as well as the influence of the cultivation time and concentration of Au/Pt/ZnO nanoparticles on the percentage of dead cells. The studies showed that the percentage of dead leukemia cells increased with the cultivation time and concentration of Au/Pt/ZnO nanoparticles. There was observed an increase in the percentage of cells in the G2/M phase, which suggests the stoppage of G2/M leading to cell death. The cytotoxicity of Au/Pt/ZnO nanoparticles determined by means of the MTT test indicated that the viability of leukemia cells practically disappeared when the concentration of the tested nanoparticles was 10 mol.