Matrix detachable coils

Matrix detachable coils (Boston Scientific Neurovascular) are another example of modified endovascular coils, employing a stainless steel delivery wire coated with a bioabsorbable copolymer of 90% polyglycolide and 10% polylactide. In a study by Murayama et al. (2003), matrix detachable coils were shown to accelerate the rate of aneurysm healing in swine aneurysm models, specifically by promoting the formation of a thick neointimal layer at the aneurysm neck more quickly bare platinum coils (Murayama et al, 2003). Taschner et al. (2005) evaluated the use of Matrix detachable coils in 25 patients with intracranial aneurysms. Again, stable emboUzed aneurysms were achieved over a six-month period, but only when Matrix coils were used in conjunction with bare platinum coils (Taschner et al, 2005). 

Taschner, C. A., Leclerc, X., Rachdi, H., Barros, A. M. Pruvo, J.-P. (2005) Matrix detachable coils for the endovascular treatment of intracranial aneurysms analysis of early angiographic and clinical outcomes. Stroke, 36, 2176-2180. 

Our experimental program is based on a simplified ellipsometer (psi meter) (46) for the in-situ measurement of resist film thickness in developer solutions. Preliminary data suggest the formation of a gel layer over the remaining glassy film under certain conditions. The interpretation of this observation can be discussed in light of the relative rates of solvent penetration into a glassy matrix and polymer coil detachment from the swollen network. This will be deferred to a forthcoming publication (39). We will concentrate only on the experimental aspect of the project. 

In the case of star polymers as test chains, the more the number of arms, the smaller the possibility for stars to be detached from the matrix once they are attached to the matrix over much longer periods. Even though star test chains are smaller, their motions are still hindered by other entangled polymer coils. If most star test chains participate in the entanglement, the amount of "free" stars is too small to be detected. So the CONTIN analysis did not show two modes for LPS84, but we do not want to deny the possible existence of self-diffusion of star test chains because I I of LPS84 evidently deviated from the single exponential decay. 

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