Collaborative Research: A Multi-Disciplinary Study of Selective Adsorption of Chiral Molecules on Mineral Surfaces

矿物表面对水溶液溶质的选择性吸附是有机分子富集、封存和组织的重要机制。这种矿物-有机物相互作用在含水层净化、生物膜形成和生命起源等各种过程中发挥着关键作用，在这方面，手性分子（左手分子和右手分子）的选择性吸附特别令人感兴趣。对氨基酸、糖和其他必需生物分子的强手性偏好是生物系统的定义特征。因此，选择左旋分子和右旋分子的非生物过程是生命起源的地球化学模型的核心。手性分子的识别和分离对于许多药物的药理活性、包装材料的生物降解、改进聚合物的开发以及许多其他在科学和工业中的应用是至关重要的。这种在中心矿物表面的手性选择性已经被理论预测，但还没有被实验证明。该提案旨在进一步记录这种行为，并研究手性有机分子选择性吸附在矿物表面的结构机制。一个多学科，合作，两部分的研究计划包括：一。矿物上手性吸附现象学：研究将通过建立矿物表面手性吸附的范围和程度，扩展以前的研究，这些研究证明了矿物表面的手性选择性。建议的实验包括：1。研究了其他手性氨基酸在方解石晶体生长表面的吸附，包括生物和非生物的。研究了手性氨基酸衍生物、糖类、核苷酸等手性物种在方解石晶体生长表面的吸附.研究了石膏和石英晶体生长表面的手性吸附，这两种矿物都是具有手性晶体生长表面的地球化学重要矿物。吸附机制-实验方法：将研究有机分子在这些矿物表面上手性吸附的结构机制。建议的实验包括：1。方解石晶体生长表面的液浸原子力显微镜成像：将在存在和不存在手性吸附物的情况下观察表面生长和溶解.使用位点特异性荧光标记：方解石表面的氨基酸吸附层将暴露于各种荧光标记，以确定吸附分子的方向和分布。这些拟议中的研究，与正在进行的吸附过程的理论模型，将导致理解手性选择的结构机制。这项工作，此外，将奠定基础，为未来的调查，adaptmicroarray技术的组合研究的矿物表面和吸附的有机物种在一个单一的实验。

ABSTRACTSelective adsorption of aqueous solutes onto mineral surfaces represents an important mechanism for the concentration, sequestration and organization of organic molecules. Such mineral-organic interactions play key roles in processes as diverse as aquifer purification, biofilm formation and the origin of life.In this regard, the selective adsorption of chiral (left-handed versus right-handed) molecules is of special interest. Strong chiral preference for amino acids, sugars and other essential biomolecules is a defining characteristic of biological systems. Abiotic processes that select left-handed versus right-handed molecules are thus central to geochemical models of life's origin. Chiral recognition and separation of molecules, furthermore, is vital to pharmacological activity of many drugs, biodegradation of packaging materials, development of improved polymers, and many other applications in science and industry.Previous work described selective adsorption of D- and L-aspartic acid, a biological amino acid, on chiral crystal growth faces of calcite. Such chiral selectivity on surfaces of a centric mineral had been predicted by theory, but had not been demonstrated experimentally. This proposal seeks to document further this behavior and to investigate structural mechanisms by which chiral organic molecules adsorb selectively on mineral surfaces. A multi-disciplinary, collaborative, two-part research program includes:I. Phenomenology of Chiral Adsorption on Minerals: Research will expand on previous studies, which demonstrated chiral selectivity on mineral surfaces, by establishing the range and extent of chiral adsorption on mineral surfaces. Proposed experiments include:1. Investigation of the adsorption of other chiral amino acids, both biological and non-biological, onto calcite crystal growth surfaces.2. Investigation of the adsorption of chiral amino acid derivatives, sugars, nucleotides and other chiral species onto calcite crystal growth surfaces.3. Investigation of chiral adsorption onto crystal growth surfaces of gypsum and quartz, both of which are geochemically important minerals that display chiral crystal growth surfaces.II. Adsorption Mechanisms - Experimental Approaches: Structural mechanisms that underlie chiral adsorption of organic molecules on these mineral surfaces will be investigated. Proposed experiments include:1. Liquid-immersion atomic force microscopy imaging of calcite crystal growth surfaces: Observations will be made of both surface growth and dissolution in the presence and absence of chiral adsorbates.2. Use of site-specific fluorescent tags: Calcite surfaces with an adsorbed layer of amino acids will be exposed to a variety of fluorescent tags to determine the orientation and distribution of adsorbed molecules.These proposed studies, in concert with ongoing theoretical models of the adsorption process, will lead to an understanding of structural mechanisms of chiral selection. This work, furthermore, will lay the groundwork for future investigations that adaptmicroarray technology to the combinatorial study numerous of mineral surfaces and adsorbed organic species in a single experiment.