A water-soluble NIR-II fluorescent probe for non-invasive real-time detection of blood ATP via optoacoustic and fluorescence imaging.

Adenosine triphosphate (ATP) is a critical biomolecule in cellular energy metabolism, with abnormal levels in the bloodstream linked to pathological conditions such as ischemia, cancer, and inflammatory disorders. Accurate and real-time detection of ATP is essential for early diagnosis and disease monitoring. However, conventional biochemical assays and other techniques suffer from limitations, including invasive sample collection, time-consuming procedures, and the inability to provide dynamic, in vivo monitoring. To address these challenges, we present a water-soluble near-infrared-II (NIR-II) fluorescent probe based on a heptamethine-cyanine/Zn[II] complex for the dual-modal detection of ATP via NIR-II fluorescence and optoacoustic imaging. The probe is designed with polyethylene glycol-functionalized benzindole groups for enhanced water solubility and biocompatibility as well as a dipicolylamine-Zn[II] complex that selectively binds ATP. Upon interaction with ATP, the probe exhibits a distinct absorption band (700-850 nm), enhanced NIR-II fluorescence (900-1200 nm, peak at 924 nm), and strong optoacoustic signals, enabling non-invasive and real-time ATP monitoring. This approach offers significant advantages over existing detection methods by combining high sensitivity and dynamic imaging capabilities. Our findings demonstrate that the selective responsiveness of the probe to ATP renders it highly suitable for real-time in vivo monitoring of ATP levels.