Automated all-in-one device for handling Magnetic Bead-Based Samples in immunoassays

Reliable processing of biospecimens such as plasma in liquid biopsy is crucial to achieving robust analytical results; however, manual procedures involved in sample preparation remain a major source of variability. Here, we present MECHA (Magnetic-Enrichment and Centrifugal-Homogenization Assembly), a fully automated system that standardizes magnetic bead (MB)-based sample handling. MECHA integrates coordinated magnetic actuation, controlled vibration, and orbital mixing to perform target capture, washing, and labeling steps with minimal operator input. The prototype was designed to process eight samples in parallel for electrochemiluminescence (ECL) detection. The signal variation was <10% across replicates. In a pilot analytical study, the MECHA-ECL pipeline enabled quantitative profiling of extracellular vesicles (EVs) from clinical plasma samples of colorectal cancer patients. The automated EV assay achieved a detection limit of 4 × 10⁴ EVs/mL, a dynamic range spanning 4 orders of magnitude, and identified EGFR and CD133 as predictive biomarkers for chemotherapy response.