Institute of Chemistry
Changchun Institute of Applied Chemistry, Chinese Academy Of SciencesNot a member yet
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Tumor Microenvironment Activated Photothermal Strategy for Precisely Controlled Ablation of Solid Tumors upon NIR Irradiation
No full textPhotothermal ablation has provided emerging and promising opportunities to further potentiate the efficacy of postoperative chemotherapy of tumor. However, it still cannot achieve a high level of selectivity because extraneous photodamage along the optical path to the tumor is unavoidable as the result of the uncontrollable distribution of the photothermal agents. In addition, it is technically difficult to keep photoirradiation localizing only on cancer cells. In this report, a new strategy is introduced for precisely controlled ablation of tumor through tumor microenvironment activated near-infrared (NIR) photothermal therapy. By taking advantage of the pH-dependent light-heat conversion property of Au@PANI nanoparticles, much higher photothermal effect at pH 6.5 than that at pH 7.4 is achieved. Therefore, in normal tissues and blood vessels, NIR irradiation cannot lead to a lethal temperature with little or no harm to normal cells. In contrast, in acidic tumor microenvironment, the photothermal effect is activated. Consequently, NIR irradiation can effectively kill cancer cells through local hyperthermia. Importantly, with the benefit of the internal and external control to switch on the photothermal ablation, the technical difficulty to precisely localize laser irradiation on tumor cells can be circumvented
Developing Conjugated Polymers with High Electron Affinity by Replacing a C-C Unit with a B <- N Unit
No full textThe key parameters of conjugated polymers are lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels. Few approaches can simultaneously lower LUMO and HOMO energy levels of conjugated polymers to a large extent (>0.5 eV). Disclosed herein is a novel strategy to decrease both LUMO and HOMO energy levels of conjugated polymers by about 0.6 eV through replacement of a C-C unit by a B <- N unit. The replacement makes the resulting polymer transform from an electron donor into an electron acceptor, and is proven by fluorescence quenching experiments and the photovoltaic response. This work not only provides an effective approach to tune the LUMO/HOMO energy levels of conjugated polymers, but also uses organic boron chemistry as a new toolbox to develop conjugated polymers with high electron affinity for polymer optoelectronic devices
Cobalt Phosphide Nanowires: Efficient Nanostructures for Fluorescence Sensing of Biomolecules and Photocatalytic Evolution of Dihydrogen from Water under Visible Light
No full textThe detection of specific DNA sequences plays an important role in the identification of disease-causing pathogens and genetic diseases, and photochemical water splitting offers a promising avenue to sustainable, environmentally friendly hydrogen production. Cobalt-phosphorus nanowires (CoP NWs) show a high fluorescence quenching ability and different affinity toward single-versus double-stranded DNA. Based on this result, the utilization of CoP NWs as fluorescent DNA nanosensors with a detection limit of 100 pm and a selectivity down to single-base mismatch was demonstrated. The use of a thrombin-specific DNA aptamer also enabled the selective detection of thrombin. The photoinduced electron transfer from the excited dye that labels the oligonucleotide probe to the CoP semiconductor led to efficient fluorescence quenching, and largely enhanced the photocatalytic evolution of hydrogen from water under visible light
NiSe Nanowire Film Supported on Nickel Foam: An Efficient and Stable 3D Bifunctional Electrode for Full Water Splitting
No full textActive and stable electrocatalysts made from earth-abundant elements are key to water splitting for hydrogen production through electrolysis. The growth of NiSe nanowire film on nickel foam (NiSe/NF) insitu by hydrothermal treatment of NF using NaHSe as Se source is presented. When used as a 3D oxygen evolution electrode, the NiSe/NF exhibits high activity with an overpotential of 270mV required to achieve 20mAcm(-2) and strong durability in 1.0M KOH, and the NiOOH species formed at the NiSe surface serves as the actual catalytic site. The system is also highly efficient for catalyzing the hydrogen evolution reaction in basic media. This bifunctional electrode enables a high-performance alkaline water electrolyzer with 10mAcm(-2) at a cell voltage of 1.63V
Upconversion nanoprobes for efficiently in vitro imaging reactive oxygen species and in vivo diagnosing rheumatoid arthritis
No full textOver-generation of reactive oxygen species (ROS) is closely associated with the biological processes of rheumatoid arthritis (RA). Thus, efficient monitoring ROS in inflammatory joints would be essential for better understanding the pathogenesis and optimizing therapeutic interventions. Herein, we designed a ratiometric nanoprobe utilizing upconversion nanoparticles (UCNPs) conjugated with chromophore labeled hyaluronic acid (HA) for high sensitively sensing ROS in the aqueous solution, bioimaging ROS in inflammatory mimic cells and diagnosing RA in vivo. In this approach, the conjugation of HA conferred UCNPs not only water solubility but also biocompatibility and ROS recognizing properties. Particularly, the HA backbone cleavage and detachment of chromophore labeled HA fragments from UCNPs induced by ROS inhibited the luminescent energy transfer (LRET) and allowed rational metric upconversion luminescence (UCL) emission as the detection signal. Importantly, the upconversion nanoprobe showed high effectiveness for early assessing the treatment response of arthritic animals to an antiarthritic drug-methotrexate (MTX). (C) 2014 Elsevier Ltd. All rights reserved
Electron-Acceptor-Dependent Light Absorption, Excited-State Relaxation, and Charge Generation in Triphenylamine Dye-Sensitized Solar Cells
No full textBy choosing a simple triphenylamine electron donor, we herein compare the influence of electron acceptors benzothiadiazole benzoic acid (BTBA) and cyanoacrylic acid (CA), on energy levels, light absorption, and dynamics of excited-state evolution and electron injection. DFT and time-dependent DFT calculations disclosed remarkable intramolecular conformational changes for the excited states of these two donor-acceptor dyes. Photoinduced dihedral angle variation occurs to the tri-phenylamine unit in the CA dye and backbone planarization happens to conjugated aromatic blocks in the BTBA dye. Femtosecond spectroscopic measurements suggested the crucial role of having a long excited-state lifetime in maintaining a high electron-injection yield because a reduced driving force for a low energy-gap dye can result in slower electron-injection dynamics
Functionalized graphene/Fe3O4 supported AuPt alloy as a magnetic, stable and recyclable catalyst for a catalytic reduction reaction
No full textHerein, branched poly-(ethylenimine) functionalized graphene/iron oxide hybrid (termed as BGNs/Fe3O4) was chosen as an efficient support material to load AuPt alloy nanoparticles for constructing a multifunctional nanocatalyst via a simple and controlled self-assembly approach. BGNs/Fe3O4 as a nanocarrier made the AuPt alloy nanoparticles uniformly distributed on the surface of BGNs/Fe3O4. The obtained multifunctional nanocatalyst was characterized by high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The nanocatalyst exhibited favorable water solubility, excellent dispersion, good stability, superparamagnetism and particularly high catalytic activity for reducing 4-nitrophenol (4-NP). Furthermore, by tuning the composition of the nanoalloy nanoparticles of the multifunctional nanocatalyst, a normalized rate constant of about 17.99 mg(-1) s(-1) was achieved, which was superior to most of the Au or Pt based nanocatalysts reported in recent years. In addition, it was proved that the magnetic Fe3O4 nanoparticles not only ensured the reuse of the nanocatalyst, but also significantly improved the catalytic activity. Thanks to the favorable catalytic activity, the obtained multifunctional nanocatalyst may hold great potential for various catalytic processes
Synthesis of tapered tetragonal nanorods of anatase TiO2 with enhanced photocatalytic activity via a sol-hydrothermal process mediated by H2O2 and NH3
No full textIn this paper, a series of tapered tetragonal nanorods of anatase TiO2 enclosed by both high-energy {100} and {001} facets and low-energy {101} facets have been fabricated via a facile sol-hydrothermal approach that is free of organic additives and erosive HF reagents. The particle size and morphology could be finely tuned by varying the volume ratio of H2O2 to NH3 added into the reaction system. The experimental results indicate that these two reagents have opposite actions in the growth of the nanorods. The photocatalytic activity of the as-synthesized nanorods towards H-2 evolution from water was investigated among the three typical samples. The highest H-2 evolution rate reaching up to 3.2 mmol h(-1) g(-1) could be achieved for the sample prepared using a mixture of 5 mL of H2O2 and 5 mL of NH3 as reaction media. This rate is about one order of magnitude higher than that of previously reported elongated truncated tetragonal bipyramids and is comparable to that of nanoparticles about 10 nm in size. The increase of photocatalytic activity was ascribed to the synergistic actions of the large surface area, surface heterojunction formed between adjacent high energy {100} or {001} facets and low energy {101} facets and 1.79 eV conduction band energy above the Fermi level
Porous CoP concave polyhedron electrocatalysts synthesized from metal-organic frameworks with enhanced electrochemical properties for hydrogen evolution
No full textDeveloping highly efficient and low-cost noble metal-free catalysts toward hydrogen evolution from water splitting is an attractive alternative strategy to solve the ever-increasing environmental contamination and energy demand. Herein, a porous CoP electrocatalyst with a concave polyhedron (CPH) structure was facilely prepared by a topological conversion strategy using Co-MOF (ZIF-67) polyhedrons as the precursor. The morphology of Co-MOFs is well inherited by the as-prepared CoP sample due to the multi-step calcination process at low temperature, which results in the formation of a porous structure. Compared with the contrastive CoP nanoparticles (NPs), the obtained porous CoP CPH electrocatalyst exhibits a remarkably enhanced electrocatalytic performance with a current density of 10 mA cm(-2) at an overpotential of 133 mV and a superior durability for the hydrogen evolution reaction (HER) in acid media. A small Tafel slope of ca. 51 mV dec(-1) reveals a Volmer-Heyrovsky mechanism during the HER. This work provided a new insight to fabricate morphology-controlled transition metal phosphides with a porous structure via topological conversion, which have importantly potential applications, such as electrocatalysis, photocatalysis and sensors, thanks to their porosity and controllability
Multifunctional NaYF4:Yb, Er@mSiO(2)@Fe3O4-PEG nanoparticles for UCL/MR bioimaging and magnetically targeted drug delivery
No full textA low toxic multifunctional nanoplatform, integrating both mutimodal diagnosis methods and antitumor therapy, is highly desirable to assure its antitumor efficiency. In this work, we show a convenient and adjustable synthesis of multifunctional nanoparticles NaYF4:Yb, Er@mSiO(2)@Fe3O4-PEG (MFNPs) based on different sizes of up-conversion nanoparticles (UCNPs). With strong up-conversion fluorescence offered by UCNPs, superparamagnetism properties attributed to Fe3O4 nanoparticles and porous structure coming from the mesoporous SiO2 shell, the as-obtained MFNPs can be utilized not only as a contrast agent for dual modal up-conversion luminescence (UCL)/magnetic resonance (MR) bio-imaging, but can also achieve an effective magnetically targeted antitumor chemotherapy both in vitro and in vivo. Furthermore, the UCL intensity of UCNPs and the magnetic properties of Fe3O4 in the MFNPs were carefully balanced. Silica coating and further PEG modifying can improve the hydrophilicity and biocompatibility of the as-synthesized MFNPs, which was confirmed by the in vitro/in vivo biocompatibility and in vivo long-time bio-distributions tests. Those results revealed that the UCNPs based magnetically targeted drug carrier system we synthesized has great promise in the future for multimodal bio-imaging and targeted cancer therapy