The ExoFLARE™ system consists of two components, a protein tag and a pro-fluorophore, which together provide unparalleled specificity and signal durability for tracking exosomes.
The kit has been designed to include the expression construct (for a single CD antigen) for cell transfection and the dye for the initial experiments. The assay can be performed in a convenient 96-well plate format.
The ExoFLARE™ exosome tracking assay utilizes a combination of a FLARE (fluorescence activating response element) protein tag linked via a transmembrane domain to the individual tetraspanin proteins CD9, CD63, and CD81, together with a pro-fluorophore dye.
Neither the protein nor the dye fluoresce in isolation; fluorescence is only achieved when the protein binds to the dye. The protein and pro-fluorophore dye form an unstable bond with a continuous turnover of the dye, which causes a change in the chemical structure, resulting in fluorescence. The continuous turnover allows for sustained fluorescence without the levels of photo-bleaching commonly associated with fluorescent proteins.
The ExoFLARE™ assay can be monitored for extensive periods to allow the tracking of the dye’ s movement.
Overview of the ExoFLARE™ principle.
Each ExoFLARE™ mammalian expression construct (for a single CD antigen) is ready to transfect into cells. The kit is now available for CD9, CD63 and CD81 exosome markers containing the ExoFLARE™ protein tag.
ExoFLARE™ plasmid map. Complete details are provided in the user guide, please refer to the documents section below.
ExoFLARE™ fluorophores are available as two main types: cell permeable and cell impermeable. The impermeable dye is negatively charged which significantly inhibits crossing of the phospholipid membrane. The permeant dye is more neutral, and so can cross the phospholipid membrane by diffusion like many other dyes or small molecules. The dyes are part of the initial kit, but can also be purchased separately. The pack sizes are 100 and 1,000 assays considering a 96-well plate format (1 well = 1 assay).
Schematics of the ExoFLARE™ principle.
The ExoFLARE™ assay is ideal for imaging individual exosomes, tracking long term movement, and detecting uptake of exosomes in non-transfected recipient cells.
Cell imaging for exosome tracking
CD9 CD63 CD81