In Vitro Epithelial Lung Cell Vitality Measurements With mm-Waves

Abstract

This work presents details of a novel measurement approach in the mm-wave range which enables the measurement of epithelial lung cells under in vitro conditions. The setup is able to perform contact- and interaction-free measurements, while providing an air-liquid interface for fully-differentiated human airway epithelial primary cells. The measurement setup is adapted to the biologic state-of-the-art cultivation environment of these cells. Therefore, all relevant components of this environment are discussed regarding their electromagnetic impact on the measurement. The utilized culture media are electrically characterized at $37 \,\mathrm{^{\circ }C}$. Planar resonators are employed as a sensor structure to translate changes within the cell layer to an electric response. The design process of the resonators is discussed, and a lumped-element model is established and fitted to measured data for evaluating the results. The fabrication process of the sensor structures is verified both biologically and electrically. A dielectric waveguide is utilized to perform temperature-compensated reflection measurements of the sensor structure. First measurement results of epithelial lung cells in the J-band from $220 \,\mathrm{G}\mathrm{Hz}$ to $325 \,\mathrm{G}\mathrm{Hz}$ are presented.