• Journal of Biomedical Engineering Research
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• v.24 no.1
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• pp.37-44
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• 2003

This experimental study is aimed at evaluating the hydrodynamic performance of newly designed self-expandable graft stents under steady flow condition. Two graft stents with different coating materials and a bare TiNi metallic stent for comparison test were used in the experiment. Pressure variation and velocity distribution at the upstream and downstream of the stents were measured at flow rates of 5, 10, and 15 l/min, respectively. Pressure loss due to insertion of the stent increased with increasing flow rate exponentially as expected. At a flow rate of 15 l/min, pressure loss of Polyure-thane(PU)-coated graft stent was 6 times higher than that of TiNi metallic stent, while the pressure loss of a porous Polytetrafluoroethylene(PTFE)-coated graft stent was comparable to a bare TiNi metallic stent. Velocity profiles of the porous PTFE-coated graft stent were similar to those of a bare TiNi metallic stent regardless of flow rate. Furthermore, the velocity profile of PU-coated graft stent revealed an asymmetrical and relatively low central velocity at a higher flow rate than 10 1/min, expecially, where the effects resulted in increases of wall shear stress and normal stress. The worse hydrodynamic behavior of PU-coated graft stent than the other two stents might be attributed to formation of folds due to poor flexibility of coated material when inserting the graft stent into the pipe with a more smaller size, which later gave rise non-symmetry of flow area, increase of surface roughness and jet flow via the crevice between the stent and cylinder wall.

• Polymer(Korea)
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• v.35 no.5
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• pp.483-487
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• 2011

For the preparation of effective non-vascular drug eluting stent (DES), pullulan acetate (PA) was investigated as a coating material for polytetrafluorethylene (PTFE)-covered stent. PA was coated on PTFE-covered stent (PTFE-stent) by dip coating technique, and then its surface morphology, drug release behavior and cellular toxicity were tested. Field emission-scanning electron microscopy (FE-SEM) result indicated that its surface was smoother after PA coating without any cracking. The sustained release behavior of paclitaxel from PA-coated PTFE membrane was observed for 80 days. Also, the biological stability of paclitaxel in the membrane was confirmed by annexin V binding assays. Furthermore, the antitumor activity was demonstrated by an in vivo test against CT-26 murine colorectal tumors. From the results, we concluded that PA was expected as a useful coating material to design an effective non-vascular DES.