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

Yuan Gu; Zheng Zhao; Guangle Niu; Han Zhang; Yiming Wang; Ryan T K Kwok; Jacky W Y Lam; Ben Zhong Tang

doi:10.1039/d0sc02097d

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

Chem Sci. 2020 May 15;11(22):5753-5758. doi: 10.1039/d0sc02097d. eCollection 2020 Jun 14.

Authors

Yuan Gu^{1

2}, Zheng Zhao^{1

2}, Guangle Niu^{1

2}, Han Zhang³, Yiming Wang^{1

2}, Ryan T K Kwok^{1

2}, Jacky W Y Lam^{1

2}, Ben Zhong Tang^{1

2

3}

Affiliations

¹ Department of Chemical and Biological Engineering , Department of Chemistry , The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction , Institute for Advanced Study , The Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong 999077 , China . Email: tangbenz@ust.hk.
² HKUST-Shenzhen Research Institute , No. 9 Yuexing 1st RD, South Area Hi-tech Park , Nanshan , Shenzhen 518057 , China.
³ Center for Aggregation-Induced Emission , SCUT-HKUST Joint Research Institute , State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China.

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 of dhBBR, we found that non-ionized dhBBR can enter cells more easily than ionized forms, which is in accordance with the concept of ion trapping. In addition, dhBBR shows superior anti-photobleaching ability to Curcumin thanks to its AIE properties. These results suggest that dhBBR can serve as a bioprobe for ion trapping.