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Research Interests:
The effect of freezing on the viability and mechanical strength of bioartificial tissues was determined under a variety of cooling conditions, with the ultimate aim of optimizing the cryopreservation process. Bioartificial tissues (i.e.... more
The effect of freezing on the viability and mechanical strength of bioartificial tissues was determined under a variety of cooling conditions, with the ultimate aim of optimizing the cryopreservation process. Bioartificial tissues (i.e. tissue-equivalents or TEs) were prepared by incubating entrapped human foreskin fibroblasts in collagen gels for a period of 2 weeks. The bioartificial tissues were frozen using a controlled rate freezer at various cooling rates (0.5, 2, 5, 20, 40 and > 1000°C/min or slam freezing). The viability (< 60 min after thawing) of the fibroblasts in the bioartificial tissue was assessed using the Ethidium Homodimer (dead cells stain red) and Hoechst Give cells stain blue) assay. Uniaxial tension experiments were performed on an MTS Microbionix System (Eden Prairie, MN) to assess the post-thaw mechanical properties (Maximum Stiffness; Ultimate Tensile Stress; and Strain to Failure) of the frozen-thawed bioartificial tissue (≤ 3 hours after thawing). Th...
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Research Interests:
The aim of this study was to better understand how to increase collagen content in and enhance mechanical properties of tissue-equivalents formed by entrapping tissue cells in fibrin gels, with the ultimate goal of developing mechanically... more
The aim of this study was to better understand how to increase collagen content in and enhance mechanical properties of tissue-equivalents formed by entrapping tissue cells in fibrin gels, with the ultimate goal of developing mechanically robust artificial tissues. The two main areas of focus were cell culture medium composition and replacement frequency relative to a base case of incubating
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While mechanical and bioprosthetic heart valves (mhv and bhv) have made a dramatic impact since their introduction in the 1960’s, the 10 year mortality after replacement is 30–55%, with reoperation rates of 2–4%/year because of mechanical... more
While mechanical and bioprosthetic heart valves (mhv and bhv) have made a dramatic impact since their introduction in the 1960’s, the 10 year mortality after replacement is 30–55%, with reoperation rates of 2–4%/year because of mechanical failure (mhv), bleeding and thromboembolic complications (mhv and bhv), and calcification (bhv). Autografts and allografts, while more successful, fall far short in supply. The need is particularly great for juveniles since neither mhv nor bhv have the capacity to grow. Thus, there is great interest in developing a new generation of tissue engineered heart valves (Anderson, 1995).
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The present disclosure relates to medical fluid delivery system for a sterile medical line production fluid free of cytokine inducing substances (CIS) is, can be removed cytokine inducing substances (CIS) module for the medical fluid from... more
The present disclosure relates to medical fluid delivery system for a sterile medical line production fluid free of cytokine inducing substances (CIS) is, can be removed cytokine inducing substances (CIS) module for the medical fluid from the medical fluid delivery system, and for the manufacture of sterile medical fluids inducing substances (CIS) cytokine-free process.
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Research Interests:
Research Interests:
Research Interests:
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Reducing costs per Wp is a major goal for the crystalline silicon solar cell industry in order to compete with electricity production costs from conventional energy resources. The MWT (metal wrap through) solar cell [1] is a promising... more
Reducing costs per Wp is a major goal for the crystalline silicon solar cell industry in order to compete with electricity production costs from conventional energy resources. The MWT (metal wrap through) solar cell [1] is a promising concept to reduce production costs by ...
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We present a novel approach to producing bioartificial valves using the tissue-equivalent method of entrapping cells within a biopolymer gel and using a mold design that presents appropriate mechanical constraints to the cell-induced gel... more
We present a novel approach to producing bioartificial valves using the tissue-equivalent method of entrapping cells within a biopolymer gel and using a mold design that presents appropriate mechanical constraints to the cell-induced gel compaction to yield both the fibril alignment and the geometry of a native valve. Bileaflet valves were fabricated from bovine collagen and neonatal human dermal fibroblasts as proof of principle. The resultant valves possessed both commissure-tocommissure alignment of collagen fibers in the leaflets and circumferential alignment in the root. While this alignment was manifested in planar biaxial tensile mechanical properties, histology of the leaflets revealed an aligned collagen matrix but lacking other extracellular matrix (ECM) components present in the native valve. The apparent lack of ECM production by the fibroblasts after contracting and aligning the collagen fibrils is consistent with peak loads during biaxial testing being only approximately 10% of native leaflet values and a 0:1 coupling index that was only approximately 50% of native leaflet values despite exhibiting comparable values for the anisotropy index.