A microwave sensor dedicated to dielectric spectroscopy of nanoliter volumes of liquids medium and flowing particles

This paper presents a RF biosensor dedicated to the microwave dielectric spectroscopy on nanoliter volumes of liquids or to the detection and analysis on flowing microscale particles. This sensor uses a microfluidic network in order to guide the liquid and drive the particles to analyze. Once properly calibrated this sensor should allow measuring the intrinsic dielectric properties of unknown liquid medium and even individual characteristics of flowing particles. Indeed characterizations done on small volumes of liquids with this device showed a good agreement with macro scale measurements done using a coaxial probe. To demonstrate its sensing capabilities, experiments with polystyrene beads have been first performed and compared with 3D electromagnetic simulations which show that potential high detection sensitivity can be expected. This opens attractive prospects in the frame of microwave dielectric spectroscopy for microanalysis of various dielectric particles like biological cells as example.