White paper 9 | Version 2 | Tobias Zbik, Filip Delport
SUMMARY
Extracellular vesicles (EVs) are an increasingly popular target in the search for novel biomarkers in the field of neuronal disease diagnostics. Investigating the composition and cargo of EVs is still challenging because it is difficult to specifically isolate these highly heterogeneous biomolecules from crude samples. 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 FO-SPR assay for the isolation of neuron-derived EVs from human plasma samples.
In this approach, the neuron-specific L1CAM transmembrane protein was used as a biomarker and target for EV isolation. Multiple capture and release cycles were tested to enrich the EV yield while using as little plasma sample as possible. Detection and signal amplification with gold nanoparticles was used to verify isolation specificity and full release of the EVs into the elution buffer.
We discuss how this FO-SPR assay can provide a fast, specific, and easy EV isolation method that is directly applicable in complex matrices. In contrast to other available isolation techniques, this method combines immune-affinity isolation with real-time monitoring in a single run. FO-SPR can simplify and improve EV isolation for analysis in this fast-developing field.