Integrated 3D Microfluidic Device for Impedance Spectroscopy in Lab-on-Chip Systems

In this paper we demonstrate the implementation of a micro-scaled integrated system with the aim to sort, estimate and monitor the biomass of living cancer cells suspended in a culture medium. For this purpose, a 3D microfluidic network is designed to route small volumes of biological samples to the testing sites and dielectric spectroscopy is chosen as investigation method. Comparative electrical analyses are guaranteed by the separation of sole medium and medium-cells mixture in two different areas of the chip. A polyimide-based micro-sieve, placed between two microfluidic channels, is used to perform cell filtering and sorting. Two couples of thin-film metal electrodes ensure the comparative dielectric measurements of the separated materials. Preliminary experiments were carried out in order to test the microfluidics and demonstrate its particle-separating capabilities. The first results prove the robustness of the chosen materials, the effectiveness of the micro-sieving device in terms of particle separation from a liquid solution and its successful integration in the microfluidics. The proposed system represents a promising step for the development of novel valid solutions in the field of micro-scaled integrated cell sorting, cell monitoring and cell counting for a wide range of applications, such as tissue engineering, tumor cells research and biological monitoring in space environment.