Described herein is a method for detecting the presence of circulating
extracellular vesicles in a subject. The method comprises contacting a biological sample from the subject with an
antibody mimetic that specifically binds to a
cell surface marker on the vesicles, wherein the
antibody mimetic is coupled to a detectable
label; and detecting presence of
extracellular vesicles in the sample by detecting the presence of the detectable
label coupled to the
antibody mimetic bound to the vesicles.