Copper Fluor-4 (CF4) is a Cu+-specific fluorescent probe based on a rhodol dye scaffold. Copper Fluor-4 has high copper selectivity with a Kd value of 2.9×10−13 M, particularly over zinc and iron, as well as abundant cellular alkali and alkaline earth metals. Copper Fluor-4 is stable in a psiologically relevant pH regime between 6 and 8 (wavelengths of 415 nm for excitation and 660 nm for emission).
Copper Fluor-4 (0.8 µM, 10 min) demonstrates localization of the copper in the soma region, which includes its localization in the perinuclear Golgi region in the PC-12-derived neurons[3].
Copper Fluor-4 (2 µM, 24 h) can be used to assess changes in labile copper distributions in small living organisms such as zebrafish embryos[1].Copper Fluor-4 (10 µM, 3 h) can be used to assess labile Cu levels with a Kd value of 2.9×10−13 M for a 1:1 copper:probe stoichiometry that is well-matched to monitor labile Cu pools by reversible Cu binding without depleting the total Cu store in worms[2].
References:
[1]. Xiao T, et al. Copper regulates rest-activity cycles through the locus coeruleus-norepinephrine system. Nat Chem Biol. 2018 Jul;14(7):655-663.
[2]. Weishaupt AK, et al. Dysfunction in atox-1 and ceruloplasmin alters labile Cu levels and consequently Cu homeostasis in C. elegans. Front Mol Biosci. 2024 Feb 8;11:1354627.
[3]. Chakraborty K, et al. Copper dependent ERK1/2 phosphorylation is essential for the viability of neurons and not glia. Metallomics. 2022 Apr 1;14(4):mfac005.