A microfluidic ExoSearch chip for multiplexed exosome detection towards blood-based ovarian cancer diagnosis

TLDR

Tumor‑derived circulating exosomes, enriched with tumor antigens, are emerging as promising biomarkers for cancer diagnosis through minimally invasive procedures, though accurately quantifying exosome tumor markers remains challenging. This study introduces ExoSearch, a simple microfluidic platform that enriches plasma exosomes for in‑situ, multiplexed detection using immunomagnetic beads. ExoSearch is a robust continuous‑flow chip that quantitatively isolates and releases exosomes from 10 µL to 10 mL plasma, enabling multiplexed measurement of exosomal tumor markers. Using the chip to measure CA‑125, EpCAM, and CD24 in ovarian cancer patient plasma yielded perfect diagnostic accuracy (AUC = 1.0, p = 0.001), comparable to the standard Bradford assay, and demonstrates a valuable platform for clinical diagnosis and exosome research.

Abstract

Tumor-derived circulating exosomes, enriched with a group of tumor antigens, have been recognized as a promising biomarker source for cancer diagnosis via a less invasive procedure. Quantitatively pinpointing exosome tumor markers is appealing, yet challenging. In this study, we developed a simple microfluidic approach (ExoSearch) which provides enriched preparation of blood plasma exosomes for in situ, multiplexed detection using immunomagnetic beads. The ExoSearch chip offers a robust, continuous-flow design for quantitative isolation and release of blood plasma exosomes in a wide range of preparation volumes (10 μL to 10 mL). We employed the ExoSearch chip for blood-based diagnosis of ovarian cancer by multiplexed measurement of three exosomal tumor markers (CA-125, EpCAM, CD24) using a training set of ovarian cancer patient plasma, which showed significant diagnostic power (a.u.c. = 1.0, p = 0.001) and was comparable with the standard Bradford assay. This work provides an essentially needed platform for utilization of exosomes in clinical cancer diagnosis, as well as fundamental exosome research.