Figure 4.

Schematic view of SPRi in combination with antibody microarray. Different antibodies are printed in replicate on a gold chip and EVs are introduced to the chip with a constant flow via a multichannel flow cell placed on top of the chip. EVs are captured based on the presence of surface antigens. The optical path from the laser passes through the coupling prism at a fixed angle of incidence and the reflection of light from the SPR-active gold surface is recorded by a charge-coupled device (CCD) camera. Capturing of EVs, by the antibodies on the chip, results in changes in the refractive index leading to changes in the reflection intensities monitored by the CCD camera. Changes in the reflection intensities are presented as resonance signal versus time.