Janelia Fluor^® 552, Haloalkane

Key Information: Janelia Fluor® 552, Haloalkane is a yellow cell-permeable fluorogenic dye with a chloroalkane handle. Also chemigenetic calcium indicator for imaging Ca²⁺ mediated responses. Upon self-labeling in WHaloCaMP modular biosensors, fluorescence output is modulated by photoinduced electron transfer (PET) to a protein based quencher.

Application: live-cell imaging as a self-labeling tag substrate. Suitable for confocal microscopy, light sheet microscropy, super resolution microscopy (SRM) techniques including dSTORM (in both live and fixed cells). In vivo functional imaging of Ca²⁺ responses (flies/mice); multiplexed functional imaging of neurons and astrocytes in zebrafish larvae; quantification of Ca²⁺ concentration using fluorescence lifetime imaging microscopy (FLIM).

Properties and Photophysical Data: Stable to fixation. Cell permeable. K_D = 87 ± 5. In the presence of EGTA (Ca²⁺ chelator) excitation and emission maxima (λ) are 561 nm and 559-578 nm, respectively; quantum yield = 0.05; extinction coefficient = 73,000 M^-1cm^-1 (measured in ethanol or TFE plus 0.1% TFA); brigthness = 3.6 mM^-1cm^-1. In the presence of saturating Ca²⁺, excitation and emission maxima (λ) are 562 nm and 565-582 nm, respectively; quantum yield = 0.25; extinction coefficient = 78,000 M^-1cm^-1 (measured in ethanol or TFE plus 0.1% TFA); brigthness = 19.5 mM^-1cm^-1.

Janelia Fluor^® is a registered trademark of Howard Hughes Medical Institute.

Sold under license from the Howard Hughes Medical Institute, Janelia Research Campus