A 3D-Printed Microfluidic Device with Integrated Electrochemical Sensors for Autonomous Habitability Assessment and Life Detection

Abstract

A 3D-printed microfluidic device coupled with a fluidic processing system was developed to enable autonomous end-to-end sample handling and electrochemical characterization of an Ocean World analogue solution – synthetic seawater (SW). This dual-channel microfluidic cell was populated with 14 electrodes and performed electrochemical measurements similar to those used in the MECA Wet Chemistry Laboratory on board NASA’s Phoenix Lander that landed on Mars in 2008. Biological and metallic redox events were evaluated using cyclic voltammetry with Au, Pt, and glassy carbon electrodes, with the latter displaying superior sensitivity and selectivity. Conductivity and pH were measured using Pt and iridium oxide electrodes respectively, and SW anions such as chloride were quantified using chronopotentiometry with a Ag electrode. The fluidic handling system demonstrated sample transportation to the microfluidic device for electrochemical measurements, and could be readily adapted to accommodate different pre-processing steps. Overall, this study demonstrates the use of electrochemical sensors as part of an autonomous microfluidic handling system that would be functionally analogous to an electrochemical instrument designed for Ocean World exploration.