Doctor of Philosophy (PhD)
Spherical vesicles consisting of phosphatidylcholines in which diacetylene groups have been inserted in the hydrocarbon tail centers give rise to hollow cylindrical tubes, known as “tubules”. The study of tubules has become an area of intense interest in recent years due to their unusual morphology, which raises several profound theoretical issues and suggests their use in a variety of applications. Tubule hollowness suggests medical and industrial encapsulations as well as filtration and purification applications. These potential uses, e.g., for drug and gene delivery, requires optimization of their morphology for the application. Tubules have many technologically desirable properties, such as a very narrow distribution in diameter and length. The ability of the hydrocarbon tails' diacetylene groups to be polymerized suggests post-assembly modifications may be possible. Tubules are also susceptible to alignment with electric and magnetic fields, and being able to manipulate tubules in these ways can lead to a variety of new and innovative applications. Our main area of study will be the exploration of tubule formation mechanisms via interactions with other molecules. The phospholipid, DC(8,9)PC (1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine), is the most heavily-studied, and therefore serves as the standard to which comparisons can be made when the tubule-forming molecule is altered or when other components are added to the system. These morphological changes are critical to one of our primary technological motivations, the encapsulation and delivery of drugs. It is hoped changes of tubule size and shape resulting from either: a) the changes we make to the tubule-forming molecule; or b) the actions of the added molecule will yield; information about tubule internal structure. For example, intrinsic curvatures, bending moduli and correlation lengths, physical properties that must play important roles in determining tubule morphology, can be measured directly in these perturbed systems and compared to pure DC(8,9)PC tubules’ moduli. Studying the effects that certain molecules have on tubule formation can give us a better idea about the structural morphology and, most importantly, may allow optimization of that morphology for a particular application.
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Garrett, Colleen Colson, "Investigation of Phospholipid Tubule Morphology for Use in Drug Delivery" (2007). LSU Doctoral Dissertations. 3505.