Abstract
The analysis of cargo proteins in exosome subpopulationshas considerablevalue in diagnostics but a translatable impact has been limited bylengthy or complex exosome extraction protocols. We describe hereina scalable, fast, and low-cost exosome extraction using an alternating(AC) magnetic field to support the dynamic mixing of antibody-coatedmagnetic beads (MBs) with serum samples within 3D-printed microfluidicchips. Zwitterionic polymer-coated MBs are, specifically, magneticallyagitated and support ultraclean exosome capture efficiencies >70%from <50 & mu;L of neat serum in 30 min. Applied herein to theimmunocapture of neuronal exosomes using anti-L1CAM antibodies, priorto the array-based assaying of & alpha;-synuclein (& alpha;-syn) contentby a standard duplex electrochemical sandwich ELISA, sub pg/mL detectionwas possible with an excellent coefficient of variation and a sample-to-answertime of & SIM;75 min. The high performance and semiautomation ofthis approach hold promise in underpinning low-cost Parkinson'sdisease diagnostics and is of value in exosomal biomarker analysesmore generally.