Endogenous Labelling of Extracellular Vesicles

A process for labelling extracellular vesicles, the process comprising

• incubating cells in a culture medium in the presence of a fluorophore whereby the fluorophore is taken up by the cells;
• and extracellular vesicles are secreted from the cells together with the fluorophore to yield fluorophore labelled extracellular vesicles;
• and
• isolating the fluorophore labelled extracellular vesicles.

The process or of any one of the preceding claims, wherein the fluorophore comprises a compound having the general structure:

• wherein
• Y is N or CH;
• R1 and R2, which may be the same or different, are each independently H;
• or are a substituted or unsubstituted, saturated or unsaturated, cyclic moiety;
• a substituted or unsubstituted, saturated or unsaturated heterocyclic moiety;
• or a substituted or unsubstituted, saturated or unsaturated, straight or branched chain alkyl moiety;
• R3 and R4, which may be the same or different, are each a substituted or unsubstituted, saturated or unsaturated, cyclic moiety;
• a substituted or unsubstituted, saturated or unsaturated heterocyclic moiety;
• or a substituted or unsubstituted, saturated or unsaturated, straight or branched chain alkyl moiety;
• and
• each of X1 and X2, is a halide selected from fluoride, chloride, bromide and iodide, or is O—Z, wherein Z is a substituted or unsubstituted alkyl or aryl group.