FIGURE 2.

A schematic overview of the EV detection bioassay. Carboxylic acid self‐assembling monolayer (COOH SAM) was first formed on the surface of a gold coated FO‐SPR probe. Capture antibodies (anti‐CD9, anti‐CD63 or anti‐EpCAM) were covalently immobilized on the surface through activated COOH groups. EVs were bound to the capture antibodies in a label‐free manner. The signal was then amplified by using biotinylated detection antibodies (^Banti‐CD9, ^Banti‐CD63 or ^Banti‐CD81) and AuNPs functionalized with anti‐biotin antibody. Stars on detection antibodies depict biotin