Small extracellular vesicles detection using dielectrophoresis-based microfluidic chip for diagnosis of breast cancer

Small extracellular vesicles (sEVs) reflect the genotype and phenotype of original cells and are biomarkers for early diagnosis and treatment monitoring of tumors. Yet, their small size and low density make them difficult to isolate and detect in body fluid samples. This study proposes a novel acDEP-Exo chip filled with transparent micro-beads, which formed a non-uniform electrical field, and finally achieved rapid, sensitive, and tunable sEVs capture and detection. The method requires only 20-50 μL of sample, achieved a limit of detection (LOD) of 161 particles/μL, and can detect biomarkers within 13 min. We applied the chip to analyze the two markers of sEV's EpCAM and MUC1 in clinical plasma samples from breast cancer (BC) patients and healthy volunteers and found that the combined evaluation of sEV's biomarkers has extremely high sensitivity, specificity and accuracy. The present study introduces an alternative approach to sEVs isolation and detection, has a great potential in real-time sEVs-based liquid biopsy.