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Magnetic aerogels from FePt and CoPt 3 directly from organic solution. NANOSCALE 2024; 16:4229-4238. [PMID: 38345355 DOI: 10.1039/d3nr05892a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Here the synthesis of magnetic aerogels from iron platinum and cobalt platinum nanoparticles is presented. The use of hydrazine monohydrate as destabilizing agent triggers the gelation directly from organic solution, and therefore a phase transfer to aqueous media prior to the gelation is not necessary. The aerogels were characterized through Transmission Electron Microscopy, Scanning Electron Microscopy, Powder X-Ray Diffraction Analysis and Argon Physisorption measurements to prove the formation of a porous network and define their compositions. Additionally, magnetization measurements in terms of hysteresis cycles at 5 K and 300 K (M-H-curves) as well as zero field cooled-field cooled measurements (ZFC-FC measurements) of the dried colloids and the respective xero- and aerogels were performed, in order to analyze the influence of the gelation process and the network structure on the magnetic properties.
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Enhanced Photon Emission of Chemiluminescent Luminophore for Ultra-Fast and Semi-Automatic Immunoassay toward Single Molecule Detection. Anal Chem 2023; 95:8070-8076. [PMID: 37167106 DOI: 10.1021/acs.analchem.3c01060] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Optical single molecule detection is normally achieved via amplifying the total emission of photons of luminophores and is strongly anticipated to extend the commercialized application of chemiluminescence (CL). To overcome the limited CL photons of molecule luminophores, herein, a nanocrystal (NC) luminophore self-amplified strategy is proposed to repetitively excite CL luminophores for amplifying the total CL photons per luminophore, which can be exploited to perform CL immunoassays (CLIAs) toward single molecule detection via employing KMnO4 as the CL triggering agent and the dual-stabilizer-capped CdTe NCs as the CL luminophore. KMnO4 can oxidize the S element from each stabilizer of mercaptopropionic acid (MPA) and release enough energy to excite the CdTe core for flash CL. The substantial MPA around each CdTe core enables every CdTe luminophore to be repetitively excited and give off amplified total CL photons in a self-enhanced way. The CL of CdTe NCs/KMnO4 can release all photons rapidly, and the collection of all these photons can be utilized to determine the model analyte of thyroid-stimulating hormone antigen (TSH) with a limit of detection of 5 ag/mL (S/N = 3), which is corresponding to about 2-4 TSH molecules in a 20 μL sample. The whole immunologic operating process can be terminated within 6 min. This strategy of repetitively breaking the CL reaction involving chemical bonds within one luminophore is promising for semi-automatic as well as fully automatic single molecule detection and extends the commercialized application of CL immunodiagnosis.
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Abstract
To assess low-abundance protein biomarkers associated with tumor progression, we have developed artificial catalytic antibodies based on well-defined metal clusters modified with rationally designed peptides, termed clusterbodies. Such clusterbodies possess favorable integrated features of matched ultrasmall sizes, intrinsic fluorescence, and enzyme-like catalytic and selective recognition properties that are inaccessible to traditional antibodies. Consequently, a quantitative assay with high accuracy and high sensitivity is established by measuring the fluorescence and catalytic chemiluminescence of metal clusters preferentially recognizing the protein biomarker, which is confirmed by the molecular-weight marker references of immunoblotting. The results of quantitative immunoblotting are highly close to that derived from the enzyme-linked immunosorbent assay, implying the reliability of this protocol. Remarkably, the detection limit of the aimed protein achieved is as low as 1.0 pg, one magnitude lower than that of the conventional immunoassay. The significant variation of expression levels of the biomarker in tumor cells evidently indicates their distinguished invasion ability. This platform has potential application in analyzing low-abundance protein biomarkers in complex biological matrixes, which is essential to corroborate tumor malignancy in early stage. It inspires the construction of clusterbody-based precise bioprobes with customized structures and integrative functions for advanced quantitative biosensing.
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Annealing-modulated nanoscintillators for nonconventional X-ray activation of comprehensive photodynamic effects in deep cancer theranostics. Theranostics 2020; 10:6758-6773. [PMID: 32550902 PMCID: PMC7295068 DOI: 10.7150/thno.41752] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 05/04/2020] [Indexed: 01/10/2023] Open
Abstract
Photodynamic therapy (PDT), which involves the generation of reactive oxygen species (ROS) through interactions of a photosensitizer (PS) with light and oxygen, has been applied in oncology. Over the years, PDT techniques have been developed for the treatment of deep-seated cancers. However, (1) the tissue penetration limitation of excitation photon, (2) suppressed efficiency of PS due to multiple energy transfers, and (3) insufficient oxygen source in hypoxic tumor microenvironment still constitute major challenges facing the clinical application of PDT for achieving effective treatment. We present herein a PS-independent, ionizing radiation-induced PDT agent composed of yttrium oxide nanoscintillators core and silica shell (Y2O3:Eu@SiO2) with an annealing process. Our results revealed that annealed Y2O3:Eu@SiO2 could directly induce comprehensive photodynamic effects under X-ray irradiation without the presence of PS molecules. The crystallinity of Y2O3:Eu@SiO2 was demonstrated to enable the generation of electron-hole (e--h+) pairs in Y2O3 under ionizing irradiation, giving rise to the formation of ROS including superoxide, hydroxyl radical and singlet oxygen. In particular, combining Y2O3:Eu@SiO2 with fractionated radiation therapy increased radio-resistant tumor cell damage. Furthermore, photoacoustic imaging of tumors showed re-distribution of oxygen saturation (SO2) and reoxygenation of the hypoxia region. The results of this study support applicability of the integration of fractionated radiation therapy with Y2O3:Eu@SiO2, achieving synchronously in-depth and oxygen-insensitive X-ray PDT. Furthermore, we demonstrate Y2O3:Eu@SiO2 exhibited radioluminescence (RL) under X-ray irradiation and observed the virtually linear correlation between X-ray-induced radioluminescence (X-RL) and the Y2O3:Eu@SiO2 concentration in vivo. With the pronounced X-RL for in-vivo imaging and dosimetry, it possesses significant potential for utilization as a precision theranostics producing highly efficient X-ray PDT for deep-seated tumors.
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Boosting the Peroxidase‐like Activity of Cobalt Ions by Amino Acid‐based Biological Species and Its Applications. Chem Asian J 2020; 15:1067-1073. [DOI: 10.1002/asia.201901673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/02/2020] [Indexed: 11/09/2022]
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Radical-Triggered Chemiluminescence of Phenanthroline Derivatives: An Insight into Radical-Aromatic Interaction. ACS OMEGA 2019; 4:15004-15011. [PMID: 31552342 PMCID: PMC6751721 DOI: 10.1021/acsomega.9b01785] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
The hitherto unknown influence of 1,10-phenonthroline (1,10-phen) and its derivatives on the weak chemiluminescence (CL) of periodate-peroxide has been investigated, and a novel method for CL catalysis is described. Herein, we have deconvoluted the variation in CL intensity arising from the addition of various derivatives of 1,10-phen. Interestingly, similar derivatives of 1,10-phen show interesting differences in their reactivity toward CL. Electron-withdrawing substituents on 1,10-phen boosted the CL signals, indicating a negative charge buildup on 1,10-phen in the rate-determining step. The 1,10-phen derivatives having substitution at the C5=C6 position resulted in no CL signals due to the blockage of the reactive site. Mechanistic investigations are interpreted in terms of free radical (H2O2 reaction), followed by the oxygen atom transfer via an electrophilic attack of IO4 - (IO4 - reaction) on 1,10-phen resulting in dioxetane with enhanced CL emission. Additionally, the relationship between electronic structures and photophysical properties was investigated using density functional theory. Our results are expected to open up promising application of 1,10-phen as a molecular catalyst, providing a new strategy for metal-free catalytic CL enhancement reaction. We believe that this would foster in gleaning more detailed information on the nature of these reactions, thereby leading to a deeper understanding of the CL mechanism.
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Efficient bacteria inactivation by ligand-induced continuous generation of hydroxyl radicals in Fenton-like reaction. JOURNAL OF HAZARDOUS MATERIALS 2019; 369:408-415. [PMID: 30784970 DOI: 10.1016/j.jhazmat.2019.02.044] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/30/2018] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
Fenton/Fenton-like reaction is often used as an efficient method to generate hydroxyl radicals (HO) for bacteria inactivation in aqueous solution. However, inactivation efficiency of bacteria in aqueous solution using Fenton/Fenton-like reactions needs to further improve as a result of transient generation of HO. In this paper, we found that the formation of Tris-Co(II) complexes could decrease the redox potential of Co(III)/Co(II), facilitating the transformation of Tris-Co(III) complexes into Tris-Co(II) complexes. Therefore, HO could be generated continuously in the presence of H2O2. Especially, Tris-Co(II) complexes are apt to combine with Escherichia Coli cells by electrostatic interactions, inducing a higher utilization ratio of the generated HO. Therefore, the proposed Tris-Co(II) complex-H2O2 system could be employed as a high-efficiency sterilizing reagent for inactivation of E. Coli. This work provides a promising strategy for bacterial inactivation via an economic and eco-friendly manner.
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Persistent generation of hydroxyl radicals in Tris-Co(ii) complex-H 2O 2 systems for long-lasting multicolored chemical lights. Chem Commun (Camb) 2019; 55:679-682. [PMID: 30565598 DOI: 10.1039/c8cc07598k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Luminol tablet-Tris-Co(ii) complex-PVP-H2O2 systems exhibit 13 hours of intensive and stable chemiluminescence (CL) due to the continuous generation of ˙OH and sustained-release. Multicolored chemical lights were prepared through CL resonance energy transfer. This work presents a new method for the fabrication of bright chemical lights in aqueous solution for emergencies.
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N-(Aminobutyl)-N-(ethylisoluminol)-functionalized gold nanoparticles on cobalt disulfide nanowire hybrids for the non-enzymatic chemiluminescence detection of H 2O 2. NANOSCALE 2018; 10:14847-14851. [PMID: 30059104 DOI: 10.1039/c8nr03990a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
N-(Aminobutyl)-N-(ethylisoluminol) (ABEI)-functionalized gold nanoparticles (AuNPs) on cobalt disulfide nanowires (ABEI/AuNPs/CoS2 NWs) are rapidly synthesized through a microwave-assisted reduction of chloroauric acid (HAuCl4) on CoS2 NWs with ABEI. The obtained nanohybrids with enhanced chemiluminescence are exploited for the non-enzymatic detection of H2O2.
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Unexpected compositional and structural modification of CoPt 3 nanoparticles by extensive surface purification. NANOSCALE 2018; 10:6382-6392. [PMID: 29561055 DOI: 10.1039/c8nr00060c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We combined synchrotron small angle X-ray scattering, X-ray fluorescence and extended X-ray absorption fine structure spectroscopy to probe the structure of chemically synthesized CoPt3 nanoparticles (NPs) after ligand removal via the commonly accepted solvent/nonsolvent approach. We showed that the improved catalytic activity of extensively purified NPs could not be explained only in terms of a "cleaner" surface. We found that extensive surface purification results in the substantial leaching of the Co atoms from the chemically synthesized CoPt3 NPs transforming them into CoPt3/Pt core/shell structures with an unexpectedly thick (∼0.5 nm) Pt shell. We indicated that the improved catalytic activity of extensively purified NPs in octyne hydrogenation reaction can be explained by the formation of CoPt3/Pt core/shell structures. Also, we demonstrated that drastic compositional and structural transformation of water transferred CoPt3 NPs was rather a result of extensive removal of native ligands via a solvent/nonsolvent approach than leaching of cobalt atoms in aqueous media. We expect that these findings can be relevant to other transition metal based multicomponent NPs.
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Abstract
We present for the first time a nonaqueous sol-gel route to produce ultrasmall (<2 nm) magnetic bimetallic CoPt3 nanoparticles (NPs). The one-pot procedure is carried out at low temperature (180 °C) using benzyl alcohol, acting as both reducing agent and solvent. The highly monodisperse CoPt3 NPs were investigated with innovative advanced X-ray methods (whole powder pattern modeling), HR-STEM, XPS, and SQUID magnetometry. XPS showed Co was mostly in metallic form, but with a very small amount of CoO on the NP surface. The spherical NPs had an ultrasmall diameter of 1.6 nm and could self-assemble in aligned linear chains, or nanobelts, of single NPs. They are superparamagnetic, with blocking temperature of ∼20 K and coercivity at 10 K of 27.9 kA m-1 (∼350 Oe). However, there is evidence of a second magnetic phase (probably CoO) in the ZFC magnetization curve, which enhances their magnetization values, without significantly affecting their superparamagnetism.
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Heterogeneous nucleation and shape transformation of multicomponent metallic nanostructures. NATURE MATERIALS 2015; 14:215-23. [PMID: 25362354 DOI: 10.1038/nmat4115] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 09/19/2014] [Indexed: 05/26/2023]
Abstract
To be able to control the functions of engineered multicomponent nanomaterials, a detailed understanding of heterogeneous nucleation at the nanoscale is essential. Here, by using in situ synchrotron X-ray scattering, we show that in the heterogeneous nucleation and growth of Au on Pt or Pt-alloy seeds the heteroepitaxial growth of the Au shell exerts high stress (∼2 GPa) on the seed by forming a core/shell structure in the early stage of the reaction. The development of lattice strain and subsequent strain relaxation, which we show using atomic-resolution transmission electron microscopy to occur through the slip of {111} layers, induces morphological changes from a core/shell to a dumbbell structure, and governs the nucleation and growth kinetics. We also propose a thermodynamic model for the nucleation and growth of dumbbell metallic heteronanostructures.
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PtFe/nitrogen-doped graphene for high-performance electrooxidation of formic acid with composition sensitive electrocatalytic activity. RSC Adv 2015. [DOI: 10.1039/c5ra05769h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A PtFe/N-doped graphene electrocatalyst with a reduced amount of Pt is developed, which shows a good catalytic performance for formic acid electrooxidation due to the synergistic effects between the NG substrate and PtFe nanoalloy.
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Electron spin resonance spectroscopy for the study of nanomaterial-mediated generation of reactive oxygen species. J Food Drug Anal 2014; 22:49-63. [PMID: 24673903 PMCID: PMC9359146 DOI: 10.1016/j.jfda.2014.01.004] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 12/18/2022] Open
Abstract
Many of the biological applications and effects of nanomaterials are attributed to their ability to facilitate the generation of reactive oxygen species (ROS). Electron spin resonance (ESR) spectroscopy is a direct and reliable method to identify and quantify free radicals in both chemical and biological environments. In this review, we discuss the use of ESR spectroscopy to study ROS generation mediated by nanomaterials, which have various applications in biological, chemical, and materials science. In addition to introducing the theory of ESR, we present some modifications of the method such as spin trapping and spin labeling, which ultimately aid in the detection of short-lived free radicals. The capability of metal nanoparticles in mediating ROS generation and the related mechanisms are also presented.
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Electron detachment dynamics of O2−(H2O): direct ab initio molecular dynamics (AIMD) approach. RSC Adv 2014. [DOI: 10.1039/c3ra45753b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Abstract
Diamond anvil cell (DAC), synchrotron X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS) techniques are used to probe the composition inside hollow γ-Fe(3)O(4) nanoparticles (NPs). SAXS experiments on 5.2, 13.3, and 13.8 nm hollow-shell γ-Fe(3)O(4) NPs, and 6 nm core/14.8 nm hollow-shell Au/Fe(3)O(4) NPs, reveal the significantly high (higher than solvent) electron density of the void inside the hollow shell. In high-pressure DAC experiments using Ne as pressure-transmitting medium, formation of nanocrystalline Ne inside hollow NPs is not detected by XRD, indicating that the oxide shell is impenetrable. Also, FTIR analysis on solutions of hollow-shell γ-Fe(3)O(4) NPs fragmented upon refluxing shows no evidence of organic molecules from the void inside, excluding the possibility that organic molecules get through the iron oxide shell during synthesis. High-pressure DAC experiments on Au/Fe(3)O(4) core/hollow-shell NPs show good transmittance of the external pressure to the gold core, indicating the presence of the pressure-transmitting medium in the gap between the core and the hollow shell. Overall, our data reveal the presence of most likely small fragments of iron and/or iron oxide in the void of the hollow NPs. The iron oxide shell seems to be non-porous and impenetrable by gases and liquids.
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Study of Nucleation and Growth Mechanism of the Metallic Nanodumbbells. J Am Chem Soc 2012; 134:4384-92. [DOI: 10.1021/ja211459p] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bimetallic nanocrystals: liquid-phase synthesis and catalytic applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:1044-60. [PMID: 21218429 DOI: 10.1002/adma.201003695] [Citation(s) in RCA: 639] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 11/29/2010] [Indexed: 05/07/2023]
Abstract
Bimetallic nanocrystals (NCs) with core/shell, heterostructure, or inter-metallic and alloyed structures are emerging as more important materials than monometallic NCs. They are expected to display not only a combination of the properties associated with two distinct metals, but also new properties and capabilities due to a synergy between the two metals. More importantly, bimetallic NCs usually show composition-dependent surface structure and atomic segregation behavior, and therefore more interesting applied potentials in various fields including electronics, engineering, and catalysis. Compared with monometallic NCs, preparation of bimetallic NCs is much more complicated and difficult to be achieved. In recent years, researchers from many groups have made great efforts in this area. This review highlights the recent progress in the chemical synthesis of bimetallic NCs. The control over morphology, size, composition, and structure of bimetallic NCs as well as the exploration of their properties and applications are discussed.
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Enhanced chemiluminescence detection of thrombin based on cerium oxide nanoparticles. Chem Commun (Camb) 2011; 47:947-9. [DOI: 10.1039/c0cc03750h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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