Search

Cryopreservation of engineered tissue equivalents (TE) has achieved limited success. Successful preservation of a functional TE or tissue could provide prolonged transplantation time windows or off-the-shelf availability of engineered tissues. A quantitative understanding of the freezing-induced cell-fluid-matrix mechanical interaction is critical towards successful preservation of functional tissue. Using quantum dot-mediated cell image deformetry, Teo et al have experimentally mapped the instantaneous deformation of a TE during freezing process and showed its resulting volume change after thawing due to fluid loss [1]. To further our understanding of the freezing-induced fluid-matrix interaction, we have developed a biphasic model that simulates the transient of thermal load, its resulting TE elastic deformation, the corresponding pressure redistribution within, and the fluid movement in the TE.Copyright © 2011 by ASME

Stents have been used as a medical device to restore blood flow in stenosed vessels. During this process of stent expansion, the balloon and stent could damage the endothelial lining of the vascular wall [Grewe, Farb] and alter the mechanical stress states of various tissue components. The subsequent tissue re-growth and vascular remodeling have been implicated among the causes leading to restenosis. Stent designs vary over a wide range from materials used, geometric shapes, fabrication methods, treatments, among many other parameters. There are many different stent designs. We have developed an internally coiled, furled helical PLLA fiber stent at our institution [Su 03, Zilberman 02, 04, 05]. We have previously shown the effect of 62°C thermal annealing on the expansive characteristics of this stent [Welch 08].Copyright © 2009 by ASME

Stents are a medical device used to restore blood flow in stenosed vessels. During the process of stent expansion, the balloon and stent could damage the endothelial lining of the vascular wall and alter the mechanical stress states of various tissue components. The evolution of stents has progressed from bare metal stents to drug eluting stents or stents coated with drugs such as Sirolimus. Drug eluting stents are currently used to address the restenosis event that occurs after implantation. These stents have been effective but late stent thrombosis has been an emerging issue with drug eluting stents. Bioresorbable stents have emerged as a potential candidate for drug eluting stents. Su 03 has shown drug-loading PLLA with curcumin can be used as an anti-inflammatory agent. We have developed an internally coiled, furled helical PLLA fiber stent at our institution [Su 03, Zilberman 02, 04, 05]. We have previously shown the effect of 62°C thermal annealing on the expansive characteristics of this stent [Welch 08].Copyright © 2009 by ASME

Stent navigation and expansion may injure vascular endothelium, including vulnerable plaque lesions. Balloon expansion and deployment of a stent can lead to injury or the endothelial lining and stretching of the arterial wall [1]. Understanding the traction forces an expanding stent imparts on the vascular wall at the endothelial surface, the underlying plaque lesions and other tissue components during expansion is an important step in improving short term stent-wall mechanics. More importantly, the long term influence of stent-vascular wall mechanical interactions in restenosis remains unknown, and this analysis may shed light on the process.Copyright © 2007 by ASME