Cell-penetrating peptide-modified quantum dots as a ratiometric nanobiosensor for the simultaneous sensing and imaging of lysosomes and extracellular pH.

The selective measurement of cellular pH at specific regions is significant for the in-depth study of cell functions and pathological processes. Herein, we combined our previously developed rhodamine B-labeled cell-penetrating peptide spirolactam derivative with quantum dots to create a ratiometric nanobiosensor for the simultaneous sensing and imaging of lysosomes and extracellular pH.