Magnetic biosensing system based on TSMC 0.35 um BioMEMS process for sensing magnetic nanobeads

The demand for more compact devices has led to the growing demand for system-on-chip (SoC) devices. In this reported work a system has been designed that would target a specific protein by using antibodies for the capture and binding. By using the TSMC 0.35 μm bio-microelectro-mechanical systems (BioMEMS) technology, a SoC device that incorporates the sensor and readout circuit into one chip is achieved. The sensor system will be able to detect the quantity of the magnetic beads on the sensor surface. The gold layer from the BioMEMS process has high sensitivity for capturing and fixing the target antibodies on top of the sensor. The system consists of a front-end sensing coil inductor and signal processor. The coil is used as the source of magnetic fields for magnetising the magnetic beads. Using a multiplexer to switch the sensor cells is a way to obtain the signal and infer the amount of the magnetic beads on a specific sensing region. Finally, UV epoxy was used to package the bonding wire of the sensor chip to make sure that biological fluids can directly drop onto the chip without short circuiting the system.