Mathies Richard A, Razu Md Enayet, Kim Jungkyu, Stockton Amanda M, Turin Paul, Butterworth Anna
1 Department of Chemistry, University of California at Berkeley , Berkeley, California.
2 Department of Mechanical Engineering, Texas Tech University , Lubbock, Texas.
Astrobiology. 2017 Sep;17(9):902-912. doi: 10.1089/ast.2017.1660.
Enceladus presents an excellent opportunity to detect organic molecules that are relevant for habitability as well as bioorganic molecules that provide evidence for extraterrestrial life because Enceladus' plume is composed of material from the subsurface ocean that has a high habitability potential and significant organic content. A primary challenge is to send instruments to Enceladus that can efficiently sample organic molecules in the plume and analyze for the most relevant molecules with the necessary detection limits. To this end, we present the scientific feasibility and engineering design of the Enceladus Organic Analyzer (EOA) that uses a microfluidic capillary electrophoresis system to provide sensitive detection of a wide range of relevant organic molecules, including amines, amino acids, and carboxylic acids, with ppm plume-detection limits (100 pM limits of detection). Importantly, the design of a capture plate that effectively gathers plume ice particles at encounter velocities from 200 m/s to 5 km/s is described, and the ice particle impact is modeled to demonstrate that material will be efficiently captured without organic decomposition. While the EOA can also operate on a landed mission, the relative technical ease of a fly-by mission to Enceladus, the possibility to nondestructively capture pristine samples from deep within the Enceladus ocean, plus the high sensitivity of the EOA instrument for molecules of bioorganic relevance for life detection argue for the inclusion of EOA on Enceladus missions. Key Words: Lab-on-a-chip-Organic biomarkers-Life detection-Planetary exploration. Astrobiology 17, 902-912.
土卫二提供了一个绝佳的机会来探测与宜居性相关的有机分子以及为外星生命提供证据的生物有机分子，因为土卫二的羽流由来自地下海洋的物质组成，这些物质具有很高的宜居潜力和丰富的有机成分。一个主要挑战是向土卫二发射仪器，这些仪器能够有效地对羽流中的有机分子进行采样，并分析具有必要检测限的最相关分子。为此，我们展示了土卫二有机分析仪（EOA）的科学可行性和工程设计，该分析仪使用微流控毛细管电泳系统对包括胺、氨基酸和羧酸在内的多种相关有机分子进行灵敏检测，羽流检测限为百万分之一（检测限为100皮摩尔）。重要的是，描述了一种捕获板的设计，该捕获板能够以200米/秒至5千米/秒的相遇速度有效地收集羽流冰颗粒，并对冰颗粒撞击进行了建模，以证明物质将被有效捕获而不会发生有机分解。虽然EOA也可以在着陆任务中运行，但前往土卫二的飞越任务相对技术难度较低，有可能从土卫二海洋深处无损捕获原始样本，再加上EOA仪器对与生命检测相关的生物有机分子具有高灵敏度，这些都表明在土卫二任务中应包含EOA。关键词：芯片实验室；有机生物标志物；生命探测；行星探索。《天体生物学》17卷，902 - 912页
