CTSB and cancer: The resulting nanoprobe can be selectively delivered into the lysosomes of cancer cells and releases Ce6 from the GO sheet by the specific activation of Cathepsin B. The activated free Ce6 triggered singlet oxygen generation and induced lysosomal destruction and cancer cell death under irradiation.432 Wang et al. constructed lysosomal-targeting nanoparticles by conjugating SA promoting group, pH transformable hexapeptide (LTP), and sugar.