Photochemical OFF/ON Cytotoxicity Switching by Using a Photochromic Surfactant with Visible Light Irradiation

Mai Shinohara; Yuya Ashikaga; Wei Xu; Sunnam Kim; Tuyoshi Fukaminato; Takuro Niidome; Seiji Kurihara

doi:10.1021/acsomega.1c06473

Photochemical OFF/ON Cytotoxicity Switching by Using a Photochromic Surfactant with Visible Light Irradiation

ACS Omega. 2022 Feb 11;7(7):6093-6098. doi: 10.1021/acsomega.1c06473. eCollection 2022 Feb 22.

Authors

Mai Shinohara¹, Yuya Ashikaga¹, Wei Xu¹, Sunnam Kim¹, Tuyoshi Fukaminato¹, Takuro Niidome¹, Seiji Kurihara¹

Affiliation

¹ Department of Applied Chemistry & Biochemistry, Graduate School of Science & Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.

Abstract

Photochemical switching of cytotoxicity by using spiropyran compounds with pyridinium and alkyl groups was investigated. The spiropyran compound, SP6, with a hexyl group as the alkyl group displayed negative photochromism, in which the hydrophilic open merocyanine form (MC form) was stable and isomerized to the hydrophobic closed spiro form (SP form) by visible light irradiation. Both MC and SP forms exhibited amphiphilicity because of the hydrophobic hexyl and hydrophilic pyridinium groups introduced. Cytotoxicity toward HeLa cells was observed for both MC and SP forms of SP6 at concentrations higher than the critical aggregation concentration of the isomers CAC_MC and CAC_SP (CAC_MC > CAC_SP), respectively. In contrast, cytotoxicity by SP6 was activated by visible light irradiation at concentrations between CAC_MC and CAC_SP; thus, photochemical switching of cytotoxicity from the OFF to ON state was achieved. Cytotoxicity was revealed to be caused by disruption of the cell membrane. The results provide an important step in developing novel next-generation photochemotherapy drugs.