White paper 5 | Version 1 | Kris Ver Donck, Filip Delport, Kim Stevens
Based on original publication: Yildizhan et al. (2021) Journal of Extracellular Vesicles. 10 (4)
Fiber-optic surface plasmon resonance (FO-SPR) is a powerful tool that harnesses the performance of surface plasmon resonance (SPR) in an easy-to-use dip-in fiber-optic configuration. This application note describes a sensitive FO-SPR assay for the specific detection and quantification of extracellular vesicles, a particularly challenging task due to the heterogeneity of EVs and the complexity of the matrices in which they are typically found, such as culture medium or blood plasma.
The bioassay buffers and EV-specific antibody pairs were optimized in developing the bioassay described here, which was capable of detecting EVs at 10³ and 104 times lower concentrations than those typically found in human blood plasma from healthy donors and cancer patients, respectively (1). Furthermore, endogenous EVs in cell culture medium could be detected without prior purification or enrichment. Finally, MCF7 breast cancer cell EVs spiked in blood plasma were selectively captured on the FO-SPR surface using anti-EpCAM antibody.
We discuss how this FO-SPR sandwich bioassay can provide a fast, specific, and accurate alternative to other available methods of EV detection directly in crude samples, thereby avoiding bias from laborious manual purification steps. FO-SPR can simplify and improve EV quantification and analysis in this fast-developing field.