The likelihood of finding intact cellular structures on the surface or in the near subsurface of the martian regolith is slim, due in part to the intense bombardment of the surface by ionizing radiation from outer space. Given that this radiation is predicted to be so intense that it would render a living cell inactive within minutes, it is logical to search for evidence of microbial life by looking for molecules produced by the breakdown of cellular matter. This “pool” of molecules, known as biomarkers, consists of a range of species with various functionalities that make them likely to interact with minerals in the martian regolith. Raman spectroscopy, a molecularly specific analysis method utilized for detecting organic biomarkers among inorganic geomaterials, suffers from low signal intensity when the concentration of organics is as low as it appears to be on the martian surface. This article describes the utility of a surface-enhanced Raman spectroscopy (SERS) method used to detect extremely low levels of biomarkers that were passively adhered to mineral surfaces in a method that represents how this interaction would take place in a natural environment on Mars. The methodology showed promise for the detection of multiple classes of biomarkers.

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开发表面增强拉曼光谱方法来检测生物地质环境中的固定有机材料

在火星风化层的表面或近地表下发现完整细胞结构的可能性很小，部分原因是来自外太空的电离辐射对表面进行了强烈轰击。鉴于这种辐射预计会非常强烈，以至于它会在几分钟内使活细胞失去活性，因此通过寻找细胞物质分解产生的分子来寻找微生物生命的证据是合乎逻辑的。这个被称为生物标志物的分子“池”由一系列具有各种功能的物种组成，这些物种可能与火星风化层中的矿物质相互作用。拉曼光谱，一种用于检测无机地质材料中有机生物标志物的分子特异性分析方法，当有机物的浓度与在火星表面看起来一样低时，它会受到低信号强度的影响。本文描述了表面增强拉曼光谱 (SERS) 方法的实用性，该方法用于检测被动粘附在矿物表面的极低水平的生物标志物，该方法代表了这种相互作用在火星上的自然环境中是如何发生的。该方法显示出检测多种生物标志物的前景。