Three-Dimensional Electrode Integration with Microwave Sensors for Precise Microparticle Detection in Microfluidics
Microwave sensors integrated with microfluidic platforms can provide the size and permittivity of single cells and microparticles. Amongst the microwave sensor topologies, the planar arrangement of electrodes is a popular choice owing to the ease of fabrication. Unfortunately, planar electrodes gene...
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Main Authors | , , , , , |
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Format | Journal Article |
Language | English |
Published |
31.01.2024
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Subjects | |
Online Access | Get full text |
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Summary: | Microwave sensors integrated with microfluidic platforms can provide the size
and permittivity of single cells and microparticles. Amongst the microwave
sensor topologies, the planar arrangement of electrodes is a popular choice
owing to the ease of fabrication. Unfortunately, planar electrodes generate a
non-uniform electric field which causes the responsivity of the sensor to
depend on the vertical position of a microparticle in the microfluidic channel.
To overcome this problem, we fabricated three-dimensional (3D) electrodes at
the coplanar sensing region of an underlying microwave resonator. The 3D
electrodes are based on SU8 polymer which is then metallized by sputter
coating. With this system, we readily characterized a mixture composed of 12 um
and 20 um polystyrene particles and demonstrated separation without any
position-related calibration. The ratio of the electronic response of the two
particle types is approximately equal to the ratio of the particle volumes,
which indicates the generation of a uniform electric field at the sensing
region. The current work obviates the need for using multiple coplanar
electrodes and extensive processing of the data for the calibration of particle
height in a microfluidic channel: as such, it enables the fabrication of more
sophisticated microwave resonators for environmental and biological
applications. |
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DOI: | 10.48550/arxiv.2401.17774 |