Novel Far-Red Fluorescent 1,4-Dihydropyridines for L‑Type Calcium Channel Imaging

Upregulation
of L-type calcium channels (LTCCs) is implicated
in
a range of cardiovascular and neurological disorders. Therefore, the
development of toolboxes that unlock fast imaging protocols in live
cells is coveted. Herein, we report a library of first-in-class far-red
small-molecule-based fluorescent ligands (FluoDiPines), able to target
LTCCs. All fluorescent ligands were evaluated in whole-cell patch-clamp
and live-cell Ca2+ imaging whereby FluoDiPine 6 was found to be the best candidate for live-cell fluorescence imaging.
Low concentration of FluoDiPine 6 (50 nM) and a quick
labeling protocol (5 min) are successfully applied to fixed and live
cells to image LTCCs with good specificity.