The
synthesis of hollow opening polyhedral cages has always been
an attractive but challenging goal, especially with regard to inorganic
polyhedral cages. Herein, we present a novel, 240-nuclearity giant
polymolybdate cage prepared via hydrothermal synthesis. This cage
is composed of 20 tripod-shaped [Mo6O22(SO3)]
n−/[Mo6O21(SO4)]
n− building
blocks with three connected vertices and 30 cubane-type [Mo4O16]
n− edge building
blocks, featuring a rare, nearly regular pentagonal dodecahedron with
a large inner cavity (diameter up to 1.8 nm) and 12 opening pentagonal
windows. This is the highest nuclearity hollow opening dodecahedral
cage reported to date. Importantly, this cage exhibits good stability
in solution, as revealed by scanning transmission electron microscopy
(STEM), TEM, UV–vis, and Raman spectra. In addition, the bulk
sample of this compound exhibits an ultrahigh proton conductivity
of 1.03 × 10–1 S cm–1 at
80 °C and 98% relative humidity, which is the highest among polyoxometalate-based
crystalline proton conductors.
Expression of a high concentration of H2S is closely related to the formation of colon cancer tumors. However, only a few H2S‐triggered theranostics agents for colon cancer have been reported to date. Now, a turn‐on theranostics agent was developed by utilizing the in situ reaction of Cu2O and endogenous H2S at colon tumor sites. Based on in vitro and in vivo experiments, excellent photoacoustic imaging and photothermal therapy were both confirmed by this in situ reaction‐activated colon cancer theranostics method. This work established a simple and efficient strategy for both diagnosis and treatment of colon cancer with a novel trigger mechanism, which provides a new route for colon cancer theranostics based on the in situ reactions at the tumor sites.
Tumor‐microenvironment‐responsive theranostics have great potential for precision diagnosis and effective treatment of cancer. Polyaniline (PANI) is the first reported pH‐responsive organic photothermal agent and is widely used as a theranostic agent. However, tumor pH‐responsive PANI‐based theranostic agents are not explored, mainly because the conversion from the emeraldine base (EB) to emeraldine salt (ES) state of PANI requires pH < 4, which is lower than tumor acidic microenvironment. Herein, a tumor pH‐responsive PANI‐based theranostic agent is designed and prepared for amplified photoacoustic imaging guided augmented photothermal therapy (PTT), through intermolecular acid–base reactions between carboxyl groups of bovine serum albumin (BSA) and imine moieties of PANI. The albumin/PANI assemblies (BSA–PANI) can convert from the EB to ES state at pH < 7, accompanied by the absorbance redshift from visible to near‐infrared region. Both in vitro and in vivo results demonstrate that tumor acidic microenvironment can trigger both the photoacoustic imaging (PAI) signal amplification and the PTT efficacy enhancement of BSA–PANI assemblies. This work not only highlights that BSA–PANI assemblies overcome the limitation of low‐pH protonation, but also provides a facile assembly strategy for a tumor pH‐responsive PANI‐based nanoplatform for cancer theranostics.
Synergistic treatment
strategies for cancer have attracted increasing
attention owing to their enhanced therapeutic effects compared with
monotherapy. Chemodynamic therapy (CDT) is an emerging and thriving
in situ treatment for cancer owing to its high regioselectivity and
activation only by endogenous substances. However, the therapeutic
effects of CDT are hindered by low reaction speeds. Here, ultrasmall
WO3–x
@γ-poly-l-glutamic
acid (WO3–x
@γ-PGA) nanoparticles
(NPs) with good photoacoustic and photothermal properties were prepared,
and their chemodynamic performance based on a Fenton-like reaction
was explored due to its good catalytic effect. The synergistic treatment
effect was also investigated by photothermal-enhanced CDT based on
single WO3–x
@γ-PGA NPs using
a penetrating near-infrared-II laser both in vitro and in vivo. This
work provides an effective treatment for cancer and further develops
the CDT.
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