As a noninvasive
deep-tissue imaging technique, photoacoustic (PA)
imaging has great application potential in biomedicine and molecular
diagnosis. The zinc ion (Zn2+), which is a necessary metal
ion in the human body, plays a very important role in the regulation
of gene transcription and metalloenzyme function. The imbalance of
Zn2+ homeostasis is also associated with a variety of neurological
diseases. Therefore, it is critically important to accurately image
the steady-state changes of Zn2+ in vivo. However, no PA
imaging method is currently available for Zn2+. To this
end, we designed and synthesized the first PA probe of Zn2+, namely, CR-1 for in situ ratiometric imaging of Zn2+ in deep tissue in vivo. The CR-1molecule, combined with Zn2+, weakened the conjugation system of the π-electron in the
CR-1 molecule, which resulted in the blue shift of its absorption
peak from 710 nm to 532 nm. The PA signal intensity decreased at 710
nm and increased at 532 nm, and the ratiometric PA signal at these
two wavelengths (PA532/PA710) showed a good
linear relationship with the concentration of Zn2+ in the
range of 0–50 μM, with a detection limit as low as 170
nM. Furthermore, this probe exhibits extremely fast responsiveness,
is highly selective, and has excellent biocompatibility. We have used
the developed PA probe for the ratiometric PA imaging of Zn2+ in the thigh tissue of mice, and we still can accurately image Zn2+ after covering chicken breast tissue on the surface of mice
thigh. In light of these outstanding features, the developed PA probe
has high potential for imaging Zn2+ in deep tissues; thus,
it will open up new avenues for the study of the complex biochemical
processes involving Zn2+ in vivo.
Photoacoustic (PA) imaging with both the high contrast of optical imaging and the high spatial resolution of ultrasound imaging, has been regarded as a robust biomedical imaging technique. Autoimmune hepatitis...
The accurate diagnosis and targeted therapy of malignant tumors face significant challenges. To address these, an oxidized molybdenum polyoxometalate-copper nanocomposite (Ox-POM@Cu) is designed and synthesized here. The doping with Cu determines the formation of oxygen vacancies, which can increase the carrier concentration in Ox-POM@Cu, accelerate electron transfer, and enhance the redox activity, thus playing an efficient catalytic role. The nanocomposite presents unique enzymatic functions characterized by a multielement catalytic activity in the tumor microenvironment (TME). In addition, it can be employed as an NIR-II photoacoustic imaging (PAI) probe and cancer therapy agent. First, it participates in a redox reaction with glutathione (GSH) in tumor tissues, activates the PAI and photothermal therapy functions via NIR-II irradiation, and depletes the GSH supply in cancerous cells. Subsequently, it catalyzes a Fenton-like reaction with H 2 O 2 in tumor tissues to form hydroxyl radicals, thereby performing a chemodynamic therapy function. The findings show that the developed nanoenzyme is very efficient in the diagnosis and treatment of malignant tumors. This work not only provides a new strategy for the design of TME-induced NIR-II PAI but also presents new insights into enhanced cancer therapy.
Photoacoustic Imaging
In article number 2102073 by Liangliang Zhang, Shulin Zhao, Hong Liang, and co‐workers, an oxidized molybdenum polyoxometalate‐copper nanocomposite is explored as a multifunctional nanoenzyme to trigger tumor microenvironment‐activated NIR‐II photoacoustic imaging and chemodynamic/photothermal combined therapy.
The
multispectral optoacoustic tomography (MSOT) technique can
be used to perform high-resolution molecular imaging under deep tissues,
which gives the technology significant prospective for clinical application.
Here, we developed a superoxide anion (O2
•–)-activated MSOT and fluorescence dual-modality imaging probe (APSA)
for early diagnosis of drug-induced liver injury (DILI). APSA can
respond quickly to O2
•–, resulting
in an absorption peak blueshift from 845 to 690 nm, which also leads
to the photoacoustic (PA) signal at 690 nm and the fluorescence signal
at 748 nm increases linearly with increasing O2
•– concentration, which can be utilized to assess the extent of liver
damage. The developed MSOT imaging method can eliminate background
interference from hematopoietic tissue by collecting the PA signals
excited at 680, 690, 740, 760, 800, 845, and 900 nm wavelengths to
achieve noninvasive in situ visual diagnosis of DILI. The developed
fluorescence imaging method can be used for the imaging of endogenous
O2
•– in living cells and anatomic
diagnosis of liver injury. The developed probe has broad application
prospects in the early diagnosis of DILI.
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