Balanced Intersystem Crossing in Iodinated Silicon-Fluoresceins Allows New Class of Red Shifted Theranostic Agents

Sultan Cetin; Zubeyir Elmazoglu; Osman Karaman; Hande Gunduz; Gorkem Gunbas; Safacan Kolemen

doi:10.1021/acsmedchemlett.1c00018

Balanced Intersystem Crossing in Iodinated Silicon-Fluoresceins Allows New Class of Red Shifted Theranostic Agents

ACS Med Chem Lett. 2021 Mar 16;12(5):752-757. doi: 10.1021/acsmedchemlett.1c00018. eCollection 2021 May 13.

Authors

Sultan Cetin¹, Zubeyir Elmazoglu², Osman Karaman², Hande Gunduz¹, Gorkem Gunbas², Safacan Kolemen^{1

3

4

5}

Affiliations

¹ Department of Chemistry, Koc University, Rumelifeneri Yolu, 34450 Istanbul, Turkey.
² Department of Chemistry, Middle East Technical University, 06800 Ankara, Turkey.
³ Surface Science and Technology Center (KUYTAM), Koc University, 34450 Istanbul, Turkey.
⁴ Boron and Advanced Materials Application and Research Center, Koc University, 34450 Istanbul, Turkey.
⁵ TUPRAS Energy Center (KUTEM), Koc University, 34450 Istanbul, Turkey.

Abstract

Iodination of the silicon-fluorescein core revealed a new class of highly cytotoxic, red-shifted and water-soluble photosensitizer (SF-I) which is also fairly emissive to serve as a theranostic agent. Singlet oxygen generation capacity of SF-I was evaluated chemically, and up to 45% singlet oxygen quantum yield was reported in aqueous solutions. SF-I was further tested in triple negative breast (MDA MB-231) and colon (HCT-116) cancer cell lines, which are known to have limited chemotherapy options as well as very poor prognosis. SF-I induced efficient singlet oxygen generation and consequent photocytotoxicity in both cell lines upon light irradiation with a negligible dark toxicity while allowing cell imaging at the same time. SF-I marks the first ever example of a silicon xanthene-based photosensitizer and holds a lot of promise as a small-molecule-based theranostic scaffold.