5 research outputs found

    An Organocatalytic System for <i>Z</i>‑Alkene Synthesis via a Hydrogen-Bonding-Assisted Photoinduced Electron Donor–Acceptor Complex

    Full text link
    A general catalytic donor for the combination of a photoinduced electron donor–acceptor (EDA) complex and energy transfer was developed. This mild and metal-free protocol allows facile access to various Z-alkenes. Mechanism studies revealed that the organophotocatalyst, 4-CzIPN, formed a distinct three-component EDA complex with redox-active esters and (C6H5O)2P(O)OH to trigger the photoredox catalysis. The E → Z isomerization was achieved via electron exchange energy transfer from 4-CzIPN

    Charge-Convertible Carbon Dots for Imaging-Guided Drug Delivery with Enhanced <i>in Vivo</i> Cancer Therapeutic Efficiency

    Full text link
    Carbon dots (CDs) are remarkable nanocarriers due to their promising optical and biocompatible capabilities. However, their practical applicability in cancer therapeutics is limited by their insensitive surface properties to complicated tumor microenvironment <i>in vivo</i>. Herein, a tumor extracellular microenvironment-responsive drug nanocarrier based on cisplatin­(IV) prodrug-loaded charge-convertible CDs (CDs–Pt­(IV)@PEG-(PAH/DMMA)) was developed for imaging-guided drug delivery. An anionic polymer with dimethylmaleic acid (PEG-(PAH/DMMA)) on the fabricated CDs–Pt­(IV)@PEG-(PAH/DMMA) could undergo intriguing charge conversion to a cationic polymer in mildly acidic tumor extracellular microenvironment (pH ∼ 6.8), leading to strong electrostatic repulsion and release of positive CDs–Pt­(IV). Importantly, positively charged nanocarrier displays high affinity to negatively charged cancer cell membrane, which results in enhanced internalization and effective activation of cisplatin­(IV) prodrug in the reductive cytosol. The <i>in vitro</i> experimental results confirmed that this promising charge-convertible nanocarrier possesses better therapeutic efficiency under tumor extracellular microenvironment than normal physiological condition and noncharge-convertible nanocarrier. The <i>in vivo</i> experiments further demonstrated high tumor-inhibition efficacy and low side effects of the charge-convertible CDs, proving its capability as a smart drug nanocarrier with enhanced therapeutic effects. The present work provides a strategy to promote potential clinical application of CDs in the cancer treatment

    Highly Efficient White-Light Emission and UV–Visible/NIR Luminescence Sensing of Lanthanide Metal–Organic Frameworks

    Full text link
    A series of new isostructural lanthanide metal–organic frameworks (Ln-MOFs), [Ln<sub>2</sub>(L)<sub>2</sub>­(DMAC)<sub>2</sub>]·​<i>n</i>H<sub>2</sub>O [Ln = La (<b>1</b>), Pr (<b>2</b>), Nd (<b>3</b>), Sm (<b>4</b>), Eu (<b>5</b>), Gd (<b>6</b>), Tb (<b>7</b>), and Tm (<b>8</b>); H<sub>4</sub>L = 5-(bis­(4-carboxy­benzyl)­amino)-isophthalic acid, DMAC = <i>N</i>,<i>N</i>′-dimethyl­acetamide], have been isolated. Single-crystal X-ray diffraction analysis reveals that all complexes exhibit a rare (4,8)-connected <b>alb-4,8-P</b> topology with binuclear [Eu<sub>2</sub>­(COO)<sub>8</sub>]<sub><i>n</i></sub> secondary building units as 8-connected nodes and H<sub>4</sub>L ligands as 4-connected nodes. Two mixed-lanthanide analogues of single-lanthanide MOFs were designed and prepared [Ln = La<sub>0.93</sub>­Eu<sub>0.02</sub>­Tb<sub>0.05</sub> (<b>9</b>) and Tm<sub>0.47</sub>­Eu<sub>0.18</sub>­Tb<sub>0.35</sub> (<b>10</b>)] by way of careful regulation of the relative concentration of lanthanide ions which are able to emit pure white light. Luminescent sensing of complexes <b>3</b> and <b>5</b> has been investigated. Strikingly, complex <b>5</b> exhibits an excellent luminescent sensing to TNP with a high <i>K</i><sub>sv</sub> value of 3.58 × 10<sup>4</sup> M<sup>–1</sup> and a low detection limit of 4.66 × 10<sup>–4</sup> mM. Complex <b>3</b> reveals high selectivity and sensitivity toward benzaldehyde (<i>K</i><sub>sv</sub> of 4.9 × 10<sup>4</sup> M<sup>–1</sup>; detection limit of 3.4 × 10<sup>–4</sup> mM). It represents the first example of an NIR luminescent MOF for sensing of benzaldehyde

    Controllable Generation of Free Radicals from Multifunctional Heat-Responsive Nanoplatform for Targeted Cancer Therapy

    Full text link
    Targeted drug delivery and controllable generation of oxygen-independent toxic free radicals in tumor hypoxia environments are of great importance in cancer therapy. Here, a thermoresponsive nanoplatform was introduced by modifying carbon-coated iron carbide (Fe<sub>5</sub>C<sub>2</sub>) nanoparticles with bovine serum albumin (BSA) to achieve better water solubility and biocompatibility. Then a type of polymerization initiator (AIPH) was effectively loaded on the surface of Fe<sub>5</sub>C<sub>2</sub>–BSA nanoparticles and sealed by a phase change material (PCM) for higher drug loading and controlled drug release stimulated by heat. Upon illumination by near-infrared light, the photothermal effect of Fe<sub>5</sub>C<sub>2</sub> nanoparticles melts the PCM, triggering the release of encapsulated AIPH to produce free radicals, which effectively kill the hypoxia cancer cells. Additionally, the special magnetic performance enables targeted and tracked therapy under the driving of an external magnetic field. What’s more, the as-prepared multifunctional theranostic nanoplatform (Fe<sub>5</sub>C<sub>2</sub>–BSA-AIPH/PCM) ingeniously combine magnetic targeting, remotely controlled drug delivery, the generation of free radicals independent of oxygen levels into a single nanoparticle for effective cancer treatment, in detail, causing cancer cells death in vitro and markedly inhibiting tumor growth in vivo. This work presents a paradigm demonstrating that enhancing the therapeutic effect based on rationally designed multifunctional nanotheranostic agent will pioneer a new way for synergistic cancer treatment and highly developing nanotechnology

    Multifunctional Theranostic Nanoplatform Based on Fe-mTa<sub>2</sub>O<sub>5</sub>@CuS-ZnPc/PCM for Bimodal Imaging and Synergistically Enhanced Phototherapy

    Full text link
    Multifunctional nanotheranostic agent with high performance for tumor site-specific generation of singlet oxygen (<sup>1</sup>O<sub>2</sub>) as well as imaging-guidance is crucial to laser-mediated photodynamic therapy. Here, we introduced a versatile strategy to design a smart nanoplatform using phase change material (PCM) to encapsulate photosensitizer (zinc phthalocyanine, ZnPc) in copper sulfide loaded Fe-doped tantalum oxide (Fe-mTa<sub>2</sub>O<sub>5</sub>@CuS) nanoparticles. When irradiated by 808 nm laser, the PCM is melted due to the hyperthermia effect from CuS nanoparticles, inducing the release of ZnPc to produce toxic <sup>1</sup>O<sub>2</sub> triggered by 650 nm light with very low power density (5 mW/cm<sup>2</sup>). Then, the produced heat and toxic <sup>1</sup>O<sub>2</sub> can kill tumor cells in vitro and in vivo effectively. Furthermore, the special properties of Fe-mTa<sub>2</sub>O<sub>5</sub> endow the nanoplatform with excellent computed tomography (CT) and <i>T</i><sub>1</sub>-weighted magnetic resonance imaging (<i>T</i><sub>1</sub>-MRI) performance for guiding and real-time monitoring of therapeutic effect. This work presents a feasible way to design smart nanoplatform for controllable generation of heat and <sup>1</sup>O<sub>2</sub>, achieving CT/<i>T</i><sub>1</sub>-MRI dual-modal imaging-guided phototherapy
    corecore