Fluorogenic and Genetically-Targeted Red-Emitting Molecular Calcium indicator

18 February 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We introduce a strategy for the fluorogenic and genetic targeting of a calcium sensor by combining a protein fluorogen with the BAPTA sensing group. The resulting dual-input probe acts like a fluorescent AND logic gate with a Ca2+-sensitive red emission that is activated only upon reaction with the protein self-labeling tag HaloTag with a 18-fold intensity enhancement. The fluorogenic targeting of the calcium probe was evidenced by the selective wash-free imaging of calcium in the nucleus of Hela cells expressing a nuclear HaloTag protein.


Fluorogenic probe
Calcium probe
fluorescent logic gate

Supplementary materials

Supplementary information
Materials and methods, synthetic methods and additional figures


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