Fluorescence Turn-on of Tetraphenylethylene Derivative by Transfer from Cyclodextrin to Liposomes, HeLa cells, and E. coli

Kosuke Masuda, Riku Omokawa, Riku Kawasaki, Yuta Mise, Yousuke Ooyama, Shogo Harada, Wataru Shinoda, Atsushi Ikeda

Chem. Eur. J. 29, e202203071 (2022).

In this study, trimethyl-β-cyclodextrin (TMe-β-CDx) and γ-cyclodextrin (γ-CDx) could dissolve a tetraphenylethylene derivative (TPE-OH₄) in water through high-speed vibration milling. The fluorescence intensity of the TMe-β-CDx-TPE-OH₄ complex was much higher than that of the γ-CDx-TPE-OH₄ complex, as the rotation of the central C=C double bond of TPE-OH₄ after photoactivation was inhibited in a smaller TMe-β-CDx cavity in comparison with the γ-CDx cavity. In contrast, the fluorescence intensity of the γ-CDx-TPE-OH₄ complex was very weak; nevertheless, it increased after the addition of liposomes due to the transfer of TPE-OH₄ from the γ-CDx cavity to the lipid membrane as a "turn-on" phenomenon. Furthermore, to apply temperature sensor, we demonstrated that the fluorescence intensity in the liposome depended on the phase transition temperature. By using the fluorescence turn-on phenomenon, TPE-OH₄ could detect the presence of HeLa cells and E. coli by fluorescence.