This project aims to develop highly-parallel, magnetically-actuated microvalves using CMOS- compatible technology. Current state-of-the-art microvalve technologies require extensive supporting experimental apparatus and do not yield true lab-on-a-chip functionality. Here, the focus is placed on true chip-scale valve arrays based on low-power, on-chip magnetic coils which are used to actuate 100 micron diameter magnetic spheres that serve as the valve sealing surface. Prior studies of magnetic bead manipulation by planar coils, spin-valve arrays, and rotating magnetic fields have focused on the transport of small 1~50 micron diameter microbeads. In this work, the paramagnetic beads are magnetized using an external permanent magnet, allowing milliampere-level currents to generate large bipolar actuation force for valve opening/closure. The magnetically-actuated valves are self-assembled over each coil in a large chip-scale array by dispersing beads onto the chip and magnetically trapping a bead on top of each valve seat. Successful development of this technology will have various applications in parallel chemical synthesis and bioanalysis devices.
Project end date: 02/03/14