Rapid Differentiation between Microplastic Particles Using Integrated Microwave Cytometry with 3D Electrodes

TL;DR

This paper presents an integrated microwave cytometry platform combining capacitive and resistive sensors with 3D electrodes for rapid, label-free differentiation of microplastic particles in liquid, enhancing environmental and biomedical analysis.

Contribution

The study introduces a novel integrated sensor system with 3D electrodes that improves speed and accuracy in identifying microplastic particles compared to traditional methods.

Findings

Successfully distinguished polystyrene and polyethylene microparticles.

Demonstrated rapid detection suitable for flow-through systems.

Showcased potential for environmental and biomedical applications.

Abstract

Rapid identification of microparticles in liquid is an important problem in environmental and biomedical applications such as for microplastic detection in water sources and physiological fluids. Existing spectro-scopic techniques are usually slow and not compatible with flow-through systems. Here we analyze single microparticles in the 14 - 20 micrometer range using a combination of two electronic sensors in the same microfluidic system: a microwave capacitive sensor and a resistive pulse sensor. Together, this integrated sen-sor system yields the effective electrical permittivity of the analyte particles. To simplify data analysis, 3D electrode arrangements were used instead of planar electrodes, so that the generated signal is unaffected by the height of the particle in the microfluidic channel. With this platform, we were able to distinguish between polystyrene (PS) and polyethylene (PE) microparticles. We showcase the sensitivity and speed of this tech-nique and discuss the implications for the future application of microwave cytometry technology in the en-vironmental and biomedical fields.