Automated Electroosmotic Digital Optofluidics for Rapid and Label-Free Protein Detection

Rapid protein detection is crucial for medical diagnosis, clinical trials, and drug development but often faces challenges in balancing sensitivity with multiplex detection, low reagent consumption, and a short detection time. In this work, we developed an automated and sensitive electroosmotic digital optofluidics (e-DOF) platform for rapid and label-free protein biomarker quantification in microliter blood samples. The hyperspectral computation reveals nanoscale morphology changes caused by target protein capture, eliminating multifarious enzyme-linked labeling. Electroosmosis-driven molecular circulation accelerates the immuno-hybridization, enhancing sensitivity (with a detection limit of 0.21 nM) and reducing the detection time to 15 min, compared to 2-3 h for a traditional enzyme-linked immunosorbent assay. In multiplex detection of hepatitis A and E IgM in 17 clinical samples, the results were completely consistent with clinical trial outcomes. This e-DOF system presents an automated, rapid, and label-free platform for multiplex detection in microliter samples, highlighting potential applications in clinical diagnosis and immunoassay research.