5 research outputs found
An Organocatalytic System for <i>Z</i>‑Alkene Synthesis via a Hydrogen-Bonding-Assisted Photoinduced Electron Donor–Acceptor Complex
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
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 cisplatinÂ(IV) prodrug-loaded charge-convertible CDs (CDs–PtÂ(IV)@PEG-(PAH/DMMA))
was developed for imaging-guided drug delivery. An anionic polymer
with dimethylmaleic acid (PEG-(PAH/DMMA)) on the fabricated CDs–PtÂ(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–PtÂ(IV). Importantly, positively charged nanocarrier displays
high affinity to negatively charged cancer cell membrane, which results
in enhanced internalization and effective activation of cisplatinÂ(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
A series
of new isostructural lanthanide metal–organic frameworks
(Ln-MOFs), [Ln<sub>2</sub>(L)<sub>2</sub>Â(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-(bisÂ(4-carboxyÂbenzyl)Âamino)-isophthalic
acid, DMAC = <i>N</i>,<i>N</i>′-dimethylÂacetamide],
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>Â(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>ÂEu<sub>0.02</sub>ÂTb<sub>0.05</sub> (<b>9</b>) and Tm<sub>0.47</sub>ÂEu<sub>0.18</sub>ÂTb<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
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
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