Morphological Properties of Dispersions of Tubule-Forming Phospholipids (Expedited Award)

脂管是一种刚性的、直的、薄壁的中空圆柱体，其固定直径约为0.75微米，轴比高达2000：1。主要研究者发现的两种制备方法仅依赖于表面活性剂在溶液中的自组织特性，但允许高产率和良好的长度分布控制。一旦形成，可以通过聚合来稳定小管，并通过在一些金属上涂覆来进一步稳定。在目前的许多用途中，管子可能会取代石墨纤维，而且它们还有一个额外的吸引力，即在生物技术和医疗应用中具有内在的生物兼容性。在这一新兴领域的研究主要集中在几种类似的双乙酰卵磷脂的单组分分散上，这是主要研究人员首次发现的形成小管的。碳氢链和头基在这些脂类中的异常堆积可能导致晶体螺旋带的产生，该带可以转化为完整的小管。该项目基于这一理论启动了两个系统的探索性研究：一个是研究将形成小管的脂类与其他不被认为形成小管的脂类混合对热和形态的影响，另一个是确定目前尚不知道的形成小管的脂类在适当的条件下是否会形成小管。主要的表征技术是在受控温度下的高倍数光学显微镜，为了获得更高的分辨率，

Lipid tubules are rigid, straight, thin-walled, hollow cylinders with a fixed diameter of about 0.75 micrometers and axial ratios as high as 2000:1. The two methods found by the principal investigator for fabricating them rely only on the self-organizing properties of surfactants in solution, and yet allow high yield and good control of the length distribution. Once formed, tubules can be stabilized by polymerization, and further stabilized by coating with some metals. Tubules could potentially replace graphitic fibers in many of their current uses, and they have the added attraction of being intrinsically biocompatible for use in biotechnological and medical applications. Research in this emerging area has concentrated on single-component dispersions of a few similar diacetylenic lecithins which were the first found by the principal investigators to form tubules. Unusual packing of the hydrocarbon chains and head groups in these lipids may lead to the production of a crystalline helical ribbon that can convert to a complete tubule. This project initiates two systematic, exploratory searches based on this theory: one for the thermal and morphological effects of mixing tubule-forming lipids with others not believed to form tubules, and another to determine if lipids not currently known to form tubules will form them if subjected to appropriate conditions. The primary characterization techniques are high power optical microscopy under controlled temperatures, and, for higher resolution,