This article presents design and testing of a microfluidic platform for immunoassay. The method is based on sandwiched ELISA, whereby the primary antibody is immobilized on nitrocelluose and, subsequently, magnetic beads are used as a label to detect the analyte. The chip takes approximately 2 h and 15 min to complete the assay. A Hall Effect sensor using 0.35-μm BioMEMS TSMC technology (Taiwan Semiconductor Manufacturing Company Bio-Micro-Electro-Mechanical Systems) was fabricated to sense the magnetic field from the beads. Furthermore, florescence detection and absorbance measurements from the chip demonstrate successful immunoassay on the chip. In addition, investigation also covers the Hall Effect simulations, mechanical modeling of the beadprotein complex, testing of the microfluidic platform with magnetic beads averaging 10 nm, and measurements with an inductor-based system.
Bhalla, Nikhil, Danny Chung, Yaw-Jen Chang, Kimberly Uy, Yi Ye, Ting-Yu Chin, Hao Yang, Dorota Pijanowska