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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Bibliographic Details
Published inarXiv.org
Main Authors Alatas, Yagmur Ceren, Tefek, Uzay, Berk Kucukoglu, Bardakci, Naz, Salehin, Sayedus, M Selim Hanay
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 31.01.2024
Subjects
Calibration
Electric fields
Electrodes
Metallizing
Microfluidics
Microparticles
Microwave sensors
Polystyrene resins
Resonators
Sensors
Topology
Vertical orientation
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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.
ISSN:2331-8422