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Updated: Jan 26, 2026

Photoconversion of Purified Fluorescent Proteins and Dual-probe Optical Highlighting in Live Cells
Published on: June 26, 2010
Detecting Zn(II) Ions in Live Cells with Near-Infrared Fluorescent Probes
Mingxi Fang1, Shuai Xia2, Jianheng Bi3
1Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA. mfang@mtu.edu.
Abstract:
Two near-infrared fluorescent probes (A and B) containing hemicyanine structures appended to dipicolylamine (DPA), and a dipicolylamine derivative where one pyridine was substituted with pyrazine, respectively, were synthesized and tested for the identification of Zn(II) ions in live cells. In both probes, an acetyl group is attached to the phenolic oxygen atom of the hemicyanine platform to decrease the probe fluorescence background. Probe A displays sensitive fluorescence responses and binds preferentially to Zn(II) ions over other metal ions such as Cd2+ ions with a low detection limit of 0.45 nM. In contrast, the emission spectra of probe B is not significantly affected if Zn(II) ions are added. Probe A possesses excellent membrane permeability and low cytotoxicity, allowing for sensitive imaging of both exogenously supplemented Zn(II) ions in live cells, and endogenously releases Zn(II) ions in cells after treatment of 2,2-dithiodipyridine.
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