Evaluating the tumor stratification with a lysosomal pH sensitive-probe by fluorescence lifetime imaging

Owing to the anaerobic metabolism in the tumor, abundant acidic metabolites are produced and accumulated in the cells. Therefore, the cells in different tumor layers are directly linked to the pH micro-environment. Nevertheless, due to the lack of robust tools, the high-efficient evaluation of the acidic micro-environment of tumor stratification faces the challenge of accurate diagnosis. We designed a new pH sensitive fluorescent lifetime probe target to lysosomes. As we expected, the fluorescence lifetime of PLN possesses a good linear fit to the pH value, which could detect the pH change at a single lysosome level in real time, and then evaluate the different acidity of tumor stratification. The probe PLN is successfully used to evaluate the tumor stratification by fluorescence lifetime imaging microscopy (FLIM) for the first time, which is of great significance in the preoperative diagnosis of clinical tumor treatment or evaluation of drug delivery effect.