Visualizing semipermeability of the cell membrane using a pH-responsive ratiometric AIEgen

Abstract

In clinical chemotherapy, some basic drugs cannot enter the hydrophobic cell membrane because of ionization in the acidic tumor microenvironment, a phenomenon known as ion trapping. In this study, we developed a method to visualize this ion trapping phenomenon by utilizing a pH-responsive ratiometric AIEgen, dihydro berberine (dhBBR). By observing the intracellular fluorescence ofdhBBR, we found that non-ionizeddhBBRcan enter cells more easily than ionized forms, which is in accordance with the concept of ion trapping. In addition,dhBBRshows superior anti-photobleaching ability toCurcuminthanks to its AIE properties. These results suggest thatdhBBRcan serve as a bioprobe for ion trapping.