Design of a Microfluidic Millimeter Wave Chip for Magnetic Beads based Biosensing

A novel method utilizing a millimeter wave and microfluidic sensor for testing magnetic beads solutions is introduced and experimentally validated for the first time. The sensor based on resonant principles is composed of an easily integrable coplanar waveguide (CPW) and a sprial-shaped defect ground structure (DGS). The transmission parameters of the sensor are simulated and analyzed when the material under test (MUT) are air, ethanol solution and magnetic bead solution. The impact of the complex permittivity and complex permeability of the MUT on the sensor's performance is also simulated. Simulation results indicate that the proposed sensor is more sensitive to changes in complex permeability. Micro-nanofabrication and on-chip measurement of the designed sensor demonstrate its capability to distinguish the presence of magnetic beads in MUT. Magnetic beads, as one of the commonly used biomarkers, have extensive applications in cell analysis and sorting. Our preliminary study provides a new perspective for the application of millimeter wave and microfluidic technology in biological fields.