Towards breathomics with MEMS-based microplasma generators

Biochemical detection based on plasma optical emissions has shown new potential use cases in the analysis of volatile compounds in breath, making it an attractive tool for critical applications in life sciences and medicine. This study explores the potential of microplasmas for breath analysis, specifically targeting biomarkers for chronic illnesses such as chronic obstructive pulmonary disease (COPD), asthma and some types of cancer. Detecting these biomarkers may impact healthcare technologies and point-of-care diagnostics significantly, improving quality of life for patients while lowering the pressure on healthcare providers. Integrating this detection method with micro-electromechanical systems (MEMS) paves the way for scalable and portable solutions. A key advantage of microplasmas is its compatibility with MEMS fabrication, allowing for compact devices suitable for both remote and at-home monitoring.

We present the design and fabrication of a microplasma device based on dielectric barrier discharge (DBD), specifically tailored for breath analysis. The device structure includes thin film aluminium electrodes patterned onto a silicon substrate, which is electrically isolated using silicon oxide, silicon nitride or stacked layers of these materials. The substrate surface can be flat or structured with 50 x 50 µm² microcavities between the electrodes to enhance plasma confinement. A dielectric coating protects the microelectrode from degradation during plasma exposure, extending the device’s lifetime, while contact pads are open for electrical interconnects. The DBD configuration can also be scaled up to linear arrays of various sizes; in this study we examine arrays of 3, 7 and 13 microplasma generators.

We analyse various design and fabrication parameters and their impact on plasma ignition, device stability and feasibility of continuous optical readout. We use technology computer-aided design (TCAD) modelling to investigate and optimise material selections, layer thicknesses and fabrication parameters that influence the microplasma performance. This work is performed within the EIC Pathfinder project BreathSense https://www.breathsense.eu/.