Alternations in the brain nitric oxide (NO) homeostasis
are associated
with a variety of neurodegeneration diseases; therefore, high-resolution
imaging of NO in the brain is essential for understanding pathophysiological
processes. However, currently available NO probes are unsuitable for
this purpose due to their poor ability to cross the blood–brain
barrier (BBB) or to image in deep tissues with spatial resolution.
Herein, we developed a photoacoustic (PA) probe with BBB crossing
ability to overcome this obstacle. The probe shows a highly selective
ratiometric response toward NO, which enables the probe to image NO
with micron resolution in the whole brain of living mice. Using three-dimensional
PA imaging, we demonstrated that the probe could be used to visualize
the detailed NO distribution in varying depth cross-sections (0–8
mm) of the living Parkinson’s disease (PD) mouse brain. We
also investigated the therapeutic properties of natural polyphenols
in the PD mouse brain using the probe as an imaging agent and suggested
the potential of the probe for screening therapeutic agents. This
study provides a promising imaging agent for imaging of NO in the
mouse brain with high resolution. We anticipate that these findings
may open up new possibilities for understanding the biological functions
of NO in the brain and the development of new imaging agents for the
diagnosis and treatment of brain diseases.
Organic dyes with absorption maxima in the second near-infrared window (NIR-II; 1000 to 1700 nm) are of great interest in biophotonics. However, because of the lack of appropriate molecular scaffolds, current research in this field is limited to cyanine dyes, and developing NIR-II–absorbing organic dyes for biophotonics remains an immense challenge. Here, we rationally designed an ethenylene-bridged BODIPY scaffold featuring excellent J-aggregation capabilities and revealed that the bridging ethylene unit is crucial for intermolecular J-coupling regulation. By integrating the electron-donating groups into the scaffold, we obtained a BODIPY dye, BisBDP2, with a J-aggregate absorption maximum of around 1300 nm. BisBDP2 J-aggregates show excellent photothermal performance, including intense photoacoustic response, and a high photothermal conversion efficiency value of 63%. In vivo results demonstrate the potential of J-aggregates for photoacoustic imaging and photothermal ablation of deep-seated tumors. This study will speed up the exploration of NIR-II–absorbing J-aggregates for future biophotonic applications.
Spatiotemporal assessment of the oxidative stress dynamics in the brain is crucial for understanding the molecular mechanism underlying neurodegenerative diseases. However, existing oxidative stress probes have poor blood‐brain barrier permeability or poor penetration depth, making them unsuitable for brain imaging. Herein, we developed a photoacoustic probe that enables real‐time imaging of oxidative stress dynamics in the mouse brain. The probe not only responds to oxidative stress in a reversible and ratiometric manner, but it can also cross the blood‐brain barrier of the mouse brain. Notably, the probe displayed excellent photoacoustic imaging of oxidative stress dynamics in the brains of Parkinson's disease mouse models. In addition, we investigated the antioxidant properties of natural polyphenols in the brain of a Parkinson's disease mouse model using the probe as an imaging agent and suggested the potential of the probe for screening anti‐oxidative stress agents.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.