One-to-three droplet generation in digital microfluidics for parallel chemiluminescence immunoassays

In digital microfluidics, droplet generation is a fundamental operation for quantitative liquid manipulation. The generation of well-defined micro-droplets on a chip with restricted device geometries has become a real obstacle for digital microfluidics platforms to be used in parallel for in vitro diagnostic applications. Here, we propose a one-to-three droplet splitting technique that is able to generate sub-microlitre droplets beyond the well-known geometry limit in electrowetting-on-dielectric digital microfluidics. Accordingly, we realized an on-chip magnetic bead chemiluminescence immunoassay for parallel detection with the one-to-three technique. With the help of the generated micro droplets, we were able to retain the magnetic beads by a significantly reduced magnetic force. We have shown the detection of five B-type natriuretic peptide analyte samples on a single chip for around 10 minutes. The correlation coefficient of the calibration curve was 0.9942, and the detection limit was lower than 5 pg mL(-1).

Automated summary

A one-to-three droplet splitting technique was proposed in this study to generate micro-droplets in digital microfluidics for parallel detection, allowing for the retention of magnetic beads by reduced magnetic force. The technique was demonstrated in an on-chip magnetic bead chemiluminescence immunoassay, showing promising results for in vitro diagnostic applications.