Dynamic-Reversible Photoacoustic Probe for Continuous Ratiometric Sensing and Imaging of Redox Status in Vivo.

Here, we report a reversible photoacoustic (PA) probe, BDP-DOH, to image the localized redox state in vivo via monitoring the dynamic changes of the redox couple, superoxide anion (O2•-) and glutathione (GSH). The probe features a significant shift in absorption between 680 and 750 nm during selective oxidation with O2•- and the reductive recovery of GSH, thus showing a reversible responsiveness in the photoacoustic intensity ratio (PA750/PA680) to successfully visualize the redox status of the tissue in situ. This redox probe with specific and sensitive photoacoustic response provides a potential technical tool toward understanding pathological formation processes.