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Nitric oxide (NO) exhibits both pro‐ and anti‐tumor effects. Therefore, real‐time in vivo imaging and quantification of tumor NO dynamics are essential for understanding the conflicting roles of NO played in pathophysiology. The current molecular probes, however, cannot provide high‐resolution imaging in deep tissues, making them unsuitable for these purposes. Herein, we designed a photoacoustic probe with an absorption maximum beyond 1000 nm for high spatial quantitative imaging of in vivo tumor NO dynamics. The probe exhibits remarkable sensitivity, selective ratiometric response behavior, and good tumor‐targeting abilities, facilitating ratiometric imaging of tumor NO throughout tumor progression in a micron‐resolution level. Using the probe as the imaging agent, we successfully quantified NO dynamics in tumor, liver and kidney. We have pinpointed an essential concentration threshold of around 80 nmol/cm3 for NO, which plays a crucial role in the "double‐edged‐sword" function of NO in tumors. Furthermore, we revealed a reciprocal relationship between the NO concentration in tumors and that in the liver, providing initial insights into the possible NO‐mediated communication between tumor and the liver. We believe that the probe will help resolve conflicting aspects of NO biology and guide the design of imaging agents for tumor diagnosis and anti‐cancer drug screening. [ABSTRACT FROM AUTHOR]

Copper dysmetabolism is associated with various neurodegenerative disorders, making high‐spatiotemporal‐resolution imaging of Cu2+ in the brain essential for understanding the underlying pathophysiological processes. Nevertheless, the current probes encounter obstacles in crossing the blood–brain barrier (BBB) and providing high‐spatial‐resolution in deep tissues. Herein, we present a photoacoustic probe capable of imaging Cu2+ dynamics in the mouse brain with high‐spatiotemporal‐resolution. The probe demonstrates selective ratiometric and reversible responses to Cu2+, while also efficiently crossing the BBB. Using the probe as the imaging agent, we successfully visualized Cu2+ in the brain of Parkinson's disease (PD) model mouse with a remarkable micron‐level resolution. The imaging results revealed a significant increase in Cu2+ levels in the cerebral cortex as PD progresses, highlighting the close association between Cu2+ alternations in the region and the disease. We also demonstrated that the probe can be used to monitor changes in Cu2+ distribution in the PD model mouse brain during L‐dopa intervention. Mechanism studies suggest that the copper dyshomeostasis in the PD mouse brain was dominated by the expression levels of divalent metal transporter 1. The application of our probe in imaging Cu2+ dynamics in the mouse brain offers valuable insights into the copper‐related molecular mechanisms underlying neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aluminum is a promising anode material for lithium‐ion batteries owing to its high theoretical capacity, excellent conductivity, and natural abundance. An anomalous size effect was observed for micron‐sized aluminum powder electrodes in this work. Experimental and theoretical investigations reveal that the insulating oxide surface layer is the underlying cause, which leads to poor electrical conductivity and limited capacity utilization when the particle is too small. Additionally, poor electrolyte wettability also accounts for the hindered reaction kinetics due to the weak polarity feature of the oxide layer. Surface grafting of polar amino groups was demonstrated to be an effective strategy to improve electrolyte wettability. The present work revealed the critical limitations and underlying mechanisms for the aluminum anode, which is crucial for its practical application. Our results are also valuable for other metallic anodes with similar issues. [ABSTRACT FROM AUTHOR]

Small organic photothermal agents (SOPTAs) that absorb in the second near‐infrared (NIR‐II, 1000–1700 nm) window are highly desirable in photothermal therapy for their good biocompatibility and deeper tissue penetration. However, the design of NIR‐II absorbing SOPTAs remains a great challenge. Herein, we report that molecular engineering of BF2 complex via strengthening the donor‐acceptor conjugation and increasing the intramolecular motions is an efficient strategy to achieve NIR‐II absorbing SOPTAs with high photothermal performance. Based on this strategy, a BF2 complex, BAF4, was designed and synthesized. BAF4 exhibits an intense absorption maximum at 1000 nm and negligible fluorescence. Notably, the nanoparticles of BAF4 achieve a high photothermal conversion efficiency value of 80 % under 1064 nm laser irradiation (0.75 W cm−2). In vitro and in vivo studies reveal the great potential of BAF4 nanoparticles in photoacoustic imaging‐guided photothermal therapy in the NIR‐II window. [ABSTRACT FROM AUTHOR]

Small organic photothermal agents (SOPTAs) that absorb in the second near‐infrared (NIR‐II, 1000–1700 nm) window are highly desirable in photothermal therapy for their good biocompatibility and deeper tissue penetration. However, the design of NIR‐II absorbing SOPTAs remains a great challenge. Herein, we report that molecular engineering of BF2 complex via strengthening the donor‐acceptor conjugation and increasing the intramolecular motions is an efficient strategy to achieve NIR‐II absorbing SOPTAs with high photothermal performance. Based on this strategy, a BF2 complex, BAF4, was designed and synthesized. BAF4 exhibits an intense absorption maximum at 1000 nm and negligible fluorescence. Notably, the nanoparticles of BAF4 achieve a high photothermal conversion efficiency value of 80 % under 1064 nm laser irradiation (0.75 W cm−2). In vitro and in vivo studies reveal the great potential of BAF4 nanoparticles in photoacoustic imaging‐guided photothermal therapy in the NIR‐II window. [ABSTRACT FROM AUTHOR]