Drug eluting stent and its characterization by coherent anti -Stokes Raman scattering microscopy
Abstract
Atherosclerosis is the blockage of a blood vessel clogged by fatty substances. To open the clogged vessel, angioplasty is usually performed and a stent is deployed to maintain the vessel open. This procedure, however, causes unwanted event, known as restenosis, in a significant portion of patients. Recent introduction of drug-eluting stents (DESs) minimized the recurrence of restenosis. While two DESs have been used clinically with great successes, there are rooms for improvement. Restenosis is still the problem for some patients and the surface-induced thrombosis is still a major factor for the ultimate failure of the stents. It is important to understand how to control the drug release from DESs to design improved DESs. One of the clinically used DESs is TAXUS stent (Boston Scientific, MA) which delivers paclitaxel for periods of months. The mechanisms of paclitaxel release were studied to understand how a drug is released from polymer matrices, and thus to gain insights into the development of the second generation of DESs. During the study, a new microscopic technology, known as coherent anti-Stokes Raman scattering (CARS) microscopy, allows an imaging of three dimensional (3D) distribution of a drug in polymer matrices. CARS images at different depth of a polymer film at time intervals provided information on how a drug is released from the polymer. On the other hand, since the biological events following stent deployment are diverse at temporal phase, it is thought that a drug needs to be delivered at appropriate release kinetics commensurate with a biological process. The current study is also focused on developing the new coating methods to load and release a drug from a stent.
Degree
Ph.D.
Advisors
Park, Purdue University.
Subject Area
Polymers|Biomedical research
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