Electrically Controlled Tunable Broadband Interferometric Dielectric Spectroscopy: Groundwork for Single Cell Analysis

Abstract

An electrically controlled tunable interference based microwave sensor is demonstrated to perform time domain detection of single particles and measure complex permittivity of cell culture mediums within the broadband range of 12–18 GHz. Following set up is required to construct deep destructive interference nulls. Quadrature hybrid (QH), voltage controlled phase shifter and attenuator are utilized for each of the two branches. These comprise a reference branch and a branch containing the material-under-test (MUT). Coplanar waveguide (CPW) design was used as the microwave sensing structure and microfluidic wells were manufactured with polydimethylsiloxane (PDMS) to contain MUT, reference and calibration materials. The capability of detecting a single particle (diameter of 6-6.4um) is reported compared to simulations. Cell culture mediums measurements of Luria Agar (LA) and Luria Broth (LB) medium over the above-mentioned bandwidth were performed to demonstrate the operation processes and lay the groundwork for future research.