fig4
![Gas probes and their application in gas therapy](https://image.oaes.cc/aa6a5fa0-e03e-450d-b14b-432058ccb8ca/4179.fig.4.jpg)
Figure 4. Applications of probes in gas therapy: (A) coumarin-based probe (DEACA) for SO2 detection[9]; (B) QM-2 for imaging drug distribution and accumulation in vivo[49]; (C) DCFH-DA for ROS evaluation in hydron therapy[45]; (D) DAF-FM DA for NO detection[59]; (E) Cy7 for imaging drug distribution and accumulation in vivo[48].