Electrowetting enabled magnetic particle immunoassay with on-chip magnetic washing

This work demonstrates a unique DMF (Digital Microfluidics) immunoassay chip with 17 microelectrodes in an area of 6×6 mm², which manipulates both electric and magnetic fields, to carry magnetic particle based immunoassay. Superparamagentic particles act as a label for the analyte in measurement and Hall sensor response indicates the presence of target analyte. This report describes magnetic washing (pulling of unbound magnetic beads) on DMF chip without any external magnet or additional component. The chip has a novel fabrication process where 600×600 micron electrodes are interspaced with a gap of 22 micron. The movement of the droplet on the chip is controlled automatically by using FPGA Altera DE0.