An AND-Gate Photoacoustic Probe for Cys and H 2 S Precise Photoacoustic Sensing in Localized Tumors.

Photoacoustic (PA) tomography has shown many promising aspects in noninvasive and precise imaging of deep-localized biomarkers. However, these traditional single-locked PA probes always face challenges in precise PA imaging with high specificity. Here, we report a novel AND-gate photoacoustic probe, BAE , to improve tumor imaging accuracy via the combination of two tumor-associated biomarkers, cysteine (Cys) and hydrogen sulfide (H 2 S). Only when Cys and H 2 S are concurrently introduced into the detection system does the absorption of BAE red-shift from the initial 680 to 810 nm, thereby showing a 5.29-fold enhancement in its PA signal at 810 nm. The good specificity of BAE is proven, since an obvious PA signal could be observed only in the solution containing both Cys and H 2 S and was not affected by other reactive sulfur species. After being taken up by tumors with the assistance of a nanomicelle, the AND-gate PA probe BAE was applied for dynamic real-time monitoring of Cys and H 2 S in vivo , achieving precise identification of tumors. This AND-gate PA probe provides a potential technical tool for precise sensing analysis of deep-seated diseases.