Abstract

Real-Time Extracellular Vesicle Detection in Blood Plasma and Serum Using FO-SPR Sensor

Yagmur Yildizhan, PhD student, KU LEUVEN

Extracellular vesicles (EVs) are nanometer-sized membrane structures that are massively released by (cancer) cells. Because their molecular content is a fingerprint of the releasing cells, they hold huge promise in the non-invasive cancer detection. However, detecting EVs often entails enrichment through complex, low-throughput and expensive methods. Here we present fully-automated fiber optic surface plasmon resonance (FO-SPR) technology for the real time quantification of EVs directly in complex biological matrices. The FO-SPR biosensor was first pre-calibrated using recombinant extracellular vesicles (rEVs) as reference material for label-free detection in buffer down to 5x10⁷ particles/mL. This sensitivity was further improved to detect 3x10⁶ particles/mL (>1000 times lower than physiological concentration in blood) by using gold nanopaticles (AuNPs)-mediated signal amplification. Importantly, this approach allowed quantification of MCF7 breast cancer cell-derived EVs directly in spiked serum and plasma samples with the same sensitivity and without requirement for sample preparation. The specificity of the assay was achieved by using anti-EpCAM antibody as capture receptor on the FO-SPR surface. Besides selective detection and high sensitivity, the real-time monitoring, fast response time and ease of operation, demonstrate the vast potential of the FO-SPR biosensor for EV detection and quantification in clinical settings.