Increasing evidence has demonstrated that lactate and adenosine triphosphate (ATP) both play important roles in regulating abnormal metabolism in the tumor microenvironment. Herein, an O2 self‐supplying catalytic nanoagent, based on tannic acid (TA)–Fe(III) coordination complexes‐coated perfluorooctyl bromide (PFOB) nanodroplets with lactate oxidases (LOX) loading (PFOB@TA–Fe(III)–LOX, PTFL), is designed for cascade metabolic‐chemodynamic therapy (CDT) by dual‐depletion of lactate and ATP with hydroxyl •OH radicals generation. Benefiting from the catalytic property of loaded LOX and O2 self‐supplying of PFOB nanodroplets, PTFL nanoparticles (NPs) efficiently deplete tumoral lactate for down‐regulation of vascular endothelial growth factor expression and supplement the insufficient endogenous H2O2 . Simultaneously, TA–Fe(III) complexes release Fe(III) ions and TA in response to intracellular up‐regulated ATP in tumor cells followed by TA‐mediated Fe(III)/Fe(II) conversion, leading to the depletion of energy source ATP and the generation of cytotoxic •OH radicals from H2O2. Moreover, TA–Fe(III) complexes provide photoacoustic contrast as imaging guidance to enhance therapeutic accuracy. As a result, PTFL NPs efficiently accumulate in tumors for suppression of tumor growth and show evidence of anti‐angiogenesis and anti‐metastasis effects. This multifunctional nanoagent may provide new insight for targeting abnormal tumor metabolism with the combination of CDT to achieve a synergistic therapeutic effect.
The focus on heavy
metal-free semiconductor nanocrystals has increased
interest in ZnSe semiconductor quantum dots (QDs) over the past decade.
Reliable and consistent incorporation of ZnSe cores into core/shell
heterostructures or devices requires empirical fit equations correlating
the lowest-energy electron transition (1S peak) to their size and
molar extinction coefficients (ε). While these equations are
known and heavily used for CdSe, CdTe, CdS, PbS, etc., they are not
well established for ZnSe and are nonexistent for ZnSe QDs with diameters
<3.5 nm. In this study, a series of ZnSe QDs with diameters ranging
from 2 to 6 nm were characterized by small-angle X-ray scattering
(SAXS), transmission electron microscopy (TEM), UV–vis spectroscopy,
and microwave plasma atomic emission spectroscopy (MP-AES). SAXS-based
size analysis enabled the practical inclusion of small particles in
the evaluation, and elemental analysis with MP-AES elucidates a nonstoichiometric
Zn:Se ratio consistent with zinc-terminated spherical ZnSe QDs. Using
these combined results, empirical fit equations correlating QD size
with its lowest-energy electron transition (i.e., 1S peak position),
Zn:Se ratio, and molar extinction coefficients for 1S peak, 1S integral,
and high-energy wavelengths are reported. Finally, the equations are
used to track the evolution of a ZnSe core reaction. These results
will enable the consistent and reliable use of ZnSe core particles
in complex heterostructures and devices.
Photoacoustic
(PA) imaging uses photon–phonon conversion
for high-resolution tomography of biological tissues and functions.
Exogenous contrast agents are often added to improve the image quality,
but the interference from endogenous molecules diminishes the imaging
sensitivity and specificity. We report a background-free PA imaging
technique based on the active modulation of PA signals via magnetic
alignment of Fe3O4@Au hybrid nanorods. Switching
the field direction creates enhanced and deactivated PA imaging modalities,
enabling a simple pixel subtraction to effectively minimize background
noises. Under an alternating magnetic field, the nanorods exhibit
PA signals of coherently periodic changes that can be converted into
a sharp peak in a frequency domain via the fast Fourier transform.
Automatic pixel-wise screening of nanorod signals performed using
a computational algorithm across a time-sequence set of PA images
regenerates a background-free PA image with significantly improved
contrast, specificity, and fidelity.
Constructing a theranostic agent for high-contrast multimodality imaging-guided synergistic therapy with long-term tumor retention and minimum systemic side effects still remains a major challenge. Herein, a hybrid microbubble-based theranostic platform...
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