重水中L-苯丙胺酸的雷射捕捉結晶化過程的研究

Abstract

過去十年間，我們將利用高倍率和高NA(Numerical aperture)的物鏡所聚焦的1064奈米連續波長雷射光壓應用在甘胺酸、脯氨酸、絲氨酸等各種不同的基本胺基酸上並成功的證實雷射捕捉誘發結晶化的現象，我們命名為「雷射捕捉結晶化」。最近幾年間，我們成功在水溶液中把L-苯丙胺酸利用雷射捕捉結晶技術結晶化並導致其無水結晶的生成，我們解釋無水結晶的生成現象是由於局部雷射加熱導致溫度超過轉變點35-37°C而產生脫水的結晶。 在這篇論文中，我們藉由控制雷射捕捉呈現出L-苯丙胺酸在重水中的單水合和無水結晶。與水溶液不同，重水溶液中雷射加熱造成局部溫度的上升的效應還不足以達到轉變點。因此，無水結晶的生成可以確定是由雷射捕捉所實現的，並且我們發現結晶生成的機率和溶液的濃度及雷射極性十分相關。完整的動力學及機構會以雷射補捉下具有其特殊排列的團簇集合體及雷射捕捉在不同極性的雷射條件下對集合體中所引起的脫水現象的觀點來討論。

For the past decade, we applied radiation pressure of an intense CW laser beam of 1064 nm to various kinds of amino acids such as glycine, proline, serine, etc, and succeeded in demonstrating their laser trapping-induced crystallization, as we named this phenomenon “Laser trapping crystallization”. Most recently, we also succeeded in laser trapping crystallization of L-phenylalanine (L-Phe) in H2O leading to the anhydrous crystal formation and explained that the anhydrous crystal formation was due to local laser heating over the transition point of 35-37°C. In this thesis, I present pseudopolymorphism of L-Phe in D2O leading to monohydrate and anhydrous forms controlled by laser trapping. Different from the H2O solution, local temperature elevated by laser heating is too low to reach the transition point of L-Phe. Hence, the formation of anhydrous crystal was surely realized by laser trapping, and it was found that the formation probability strongly depends on solution concentration and laser polarization. The entire dynamics and mechanism is discussed in view of formation of cluster assembly characteristic under laser trapping and laser trapping-induced dehydration in the assembly depending on laser polarization.