A Rhodamine-coumarin Triazole Conjugate as a Fluorescent Chemodosimeter for Cu(II) Detection and its Application in Live Cell Bioimaging

Kanokorn Wechakorn; Chariwat Pitsanuwong; Phongthon Kanjanasirirat; Yongyut Pewkliang; Suparerk Borwornpinyo; Palangpon Kongsaeree

doi:10.1007/s10895-023-03460-4

A Rhodamine-coumarin Triazole Conjugate as a Fluorescent Chemodosimeter for Cu(II) Detection and its Application in Live Cell Bioimaging

J Fluoresc. 2023 Oct 14. doi: 10.1007/s10895-023-03460-4. Online ahead of print.

Authors

Kanokorn Wechakorn^{1

2}, Chariwat Pitsanuwong³, Phongthon Kanjanasirirat⁴, Yongyut Pewkliang⁴, Suparerk Borwornpinyo^{4

5}, Palangpon Kongsaeree^{6

7}

Affiliations

¹ Department of Chemistry, Faculty of Science and Technology, Rajamangala University of Technology, Thanyaburi, Pathum Thani, 12110, Thailand. kanokorn_w@rmutt.ac.th.
² Advanced Photochemical and Electrochemical Materials Research Unit, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Pathum Thani, 12110, Thailand. kanokorn_w@rmutt.ac.th.
³ Faculty of Science and Technology, Suan Sunandha Rajabhat University, Bangkok, 10300, Thailand.
⁴ Excellent Center for Drug Discovery, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
⁵ Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
⁶ Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. palangpon.kon@mahidol.ac.th.
⁷ Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. palangpon.kon@mahidol.ac.th.

PMID: 37837510
DOI: 10.1007/s10895-023-03460-4

Abstract

A rhodamine-triazole fluorescent probe bearing a coumarin moiety RTC was synthesized using the Cu(I)-catalyzed click reaction. The rhodamine-triazole conjugate was highly selective to Cu²⁺ among other metal ions, including Ca²⁺, Co²⁺, Cu²⁺, Cd²⁺, Mg²⁺, Fe²⁺, Fe³⁺, Hg²⁺, Zn²⁺, Ni²⁺, Pd²⁺ and Pb²⁺ in physiological conditions. Upon the addition of Cu²⁺, the colorless RTC solution turned pink and exhibited a significant fluorescence emission centered at 578 nm. The binding of Cu²⁺ induced a hydrolysis reaction, leading to a release of the coumarin unit from the rhodamine probe, as confirmed by mass spectrometric data. From the fluorescence titration, the detection limit of RTC for Cu²⁺ was determined to be 21 nM (1.3 ppb). The sensor was responsive to Cu²⁺ in a wide pH range and successfully applied to monitor Cu²⁺ in HEK293T cells by confocal fluorescence imaging.

Keywords: 1,2,3-Triazole; Bioimaging; Coumarin; Cu(II)-selective fluorescent sensor; Fluorescent sensor; Rhodamine.