Fig. 14.

Optical imaging of tumor pH. Chemical structure of phosphorus-substituted rhodamine-based probe (a). pH calibration curves of several substituted rhodamine probes based on the ratio of fluorescence intensity at 650 nm and 705 nm with pKa values of the probes given in parentheses (b). In vivo fluorescence ratio images of mice with subcutaneous tumors (c, K kidney, N normal tissue, T tumor). Graph of mean pH values for normal tissue and tumor (d). Adapted with permission from Journal of the American Chemical Society 2018, 140, 5925–5933, doi:10.1021/jacs.8b00277. Copyright 2018 American Chemical Society