ExoBrite™ STORM CTB EV Staining Kits

ExoBrite™ STORM CTB EV Stains incorporate a selection of CF® Dyes validated for stochastic optical reconstruction microscopy (dSTORM) and were developed for STORM imaging of extracellular vesicles (EVs).

Note: The name of this product has been revised from ExoBrite™ STORM EV Membrane Staining Kits.

Extracellular vesicles (EVs), including exosomes, are lipid-bound vesicles that are released from cells. EVs display specific surface proteins and can carry nucleic acids and other cargo, allowing them to transfer biological information between cells in different parts of the body. Therefore, EVs are increasingly studied for their potential use in drug delivery and medical diagnostic applications. Super-resolution microscopy techniques such as direct stochastic optical reconstruction microscopy (dSTORM) push beyond the diffraction limit of traditional light microscopy, allowing single-molecule resolution of subcellular structures, such as the proteins found on EVs.

ExoBrite™ STORM CTB EV Stains are optimally formulated fluorescent conjugates of cholera toxin subunit B (CTB), which binds to GM1 gangliosides that are commonly found on the surface of mammalian lipid rafts and EVs. The stains were developed for STORM imaging of EVs and incorporate a selection of our STORM-validated CF® Dyes. Unlike other lipophilic dyes traditionally used to stain EV membranes, ExoBrite™ STORM CTB EV Stains were formulated to show little to no background from aggregation in buffer only controls, allowing EVs to be accurately identified.

The ExoBrite™ STORM dyes CF®505, CF®583R, CF®647, and CF®680 have all been validated for use in dSTORM. In addition, ExoBrite™560/585 CTB EV Stain has also been validated for dSTORM on the ONI Nanoimager S Mark II together with fluorescent tetraspanin antibodies, allowing single-EV characterization studies.

Super-resolution dSTORM images of human colorectal cancer cell line derived EVs. EVs were stained with anti-tetraspanin antibodies (an anti-CD9/CD63/CD81 cocktail, all conjugated to CF®647, shown in magenta) together with 1X ExoBrite™ 560/585 (in cyan). Samples were prepared using ONI’s EV Profiler Kit and acquired using the Nanoimager S Mark II from ONI (Oxford Nanoimaging, UK). Data was processed using a beta-release version of CODI, ONI’s cloud-based data analysis platform. Scale bars are 500 nm (zoomed out, left panel) and 50 nm for single-EV panels (right). Image courtesy of ONI.

Biotium also offers other ExoBrite™ EV Stains and ExoBrite™ Antibody Conjugates

ExoBrite™ staining can be combined with antibody staining (for example, antibodies against tetraspanin proteins CD9, CD63, & CD81), for multi-parameter analysis. Biotium provides ExoBrite™ STORM Antibodies using CF® Dyes optimized for super-resolution STORM imaging, as well as ExoBrite™ antibodies designed for detection of EVs by flow cytometry or western blot. Biotium also offers ExoBrite™ CTB EV Stains validated for detection of purified or bead-bound EVs by flow cytometry.

ExoBrite™ STORM CTB EV Staining Kits

Validated EV Sources for ExoBrite™ CTB EV Stains