A Microfluidic Device Integrating Magnetic Stirring with Tangential Flow for High-Efficiency Isolation of Small Extracellular Vesicles

Small extracellular vesicles (sEVs), which are ubiquitously present in bodily fluids, hold significant promise as biomarkers for disease diagnosis and targeted therapy. However, their isolation remains challenging due to their small size (typically < 200   nm) and the complexity of biological fluids. This study presents a novel microfluidic strategy integrating Magnetic Stirring with Tangential Flow Filtration (MS-TFF). The automated, portable device (palm-sized, 12.5   cm × 11.1   cm × 6.25   cm) features user-friendly operation: inserting the chip into a slot and closing the lid initiates automated sEV extraction. The system processes 10   mL of morning urine or cell culture supernatant within ~40   minutes. Compared to ultracentrifugation (UC), MS-TFF reduces processing time from ~4   hours to ~40   minutes while achieving a 6-fold higher sEV yield. Clinical validation using urine from 16 subjects (6 healthy/10 prostate cancer patients) enabled quantitative ⁎ KLK3/PCA3 ⁎ RNA biomarker detection, achieving AUC = 0.93 for cancer diagnosis, confirming its diagnostic potential.