Microchip Capillary Electrophoresis for <i>In Situ</i> Planetary Exploration

摘要

NASA's Solar System exploration goals, particularly in the growing field of astrobiology, involve investigations of a variety of planetary bodies for which sample return missions are neither practical nor affordable (e.g., Europa, Titan, etc.). For these targets, in situ analyses are the only feasible option, and are ideally addressed by in situ instruments capable of wet-chemical analyses of complex mixtures on planets, moons, and primitive bodies. Instrumentation of this kind must be capable of autonomous function aboard a robotically controlled vehicle that collects data and relays it back to Earth. Due to the low power, mass, and volume requirements and extreme sensitivity enabled by lab-on-a-chip analyses, microcapillary electrophoresis is uniquely suited to meet these analytical needs. Although this technology can be adapted for a variety of different Solar System targets (including Titan, Europa, Enceladus, etc.), the bulk of development efforts to date have focused on the Mars Organic Analyzer (MOA), a portable microchip capillary electrophoresis instrument developed for ultrasensitive biomolecular analysis on Mars. MOA technology utilizes a multiwafer stack configuration containing microfluidic valving for fluidic manipulation prior to electrophoresis with ultrasensitive (sub parts per trillion) laser-induced fluorescence detection. In this chapter, we outline the state-of-the-art in this area, and also investigate future directions and applications of microfluidic technology in planetary exploration.