Abstract: The invention relates to methods for detecting and/or characterising a nanovesicle in a sample or a method of detecting a target that is bound or associated with said nanovesicle, wherein the sample is brought into contact with nanoparticles that are capable of binding on the surface of nanovesicle and form, in situ, a nanoshell that surround said nanovesicle. In a preferred embodiment, the nanovesicle is exosome labelled with fluorescent probes and the nanoparticles are gold nanoparticles (AuNP). The invention also relates to a kit or microfluidic chip for performing such methods, as well as a method of determining the prognosis of a cancer in a subject by performing such methods.