Whole-organ perfusion decellularization was performed with rat hearts on a modified chromatography apparatus. Analysis of the flow properties and effluent material over time provided insights into the decellularization process, and allowed non-destructive testing of perfused cardiac tissue. Decellularized matrices were stored for up to 1 year at -80°C and then conditioned to remove residual detergent and cryoprotectant. Tissue was reseeded with canine blood outgrowth endothelial cells (BOECs) and cultured in an autoclavable closed-circuit bubble-free reactor. The entire process was considered in the context of eventual scale-up in equipment design, the use of disposable components, and extracellular matrix (ECM) product storage. Tissue patch substrates for cell growth were studied for cytotoxic effects towards process development. Decellularization protocols were compared. Extracellular matrix derived coatings and gels were investigated as process assays and potential cell delivery vehicles. Peracetic acid and UV disinfection were tested. Micronized ECM carriers were developed for scalable culture, with considerations to carrier morphology, cell attachment, and egress. Micronized ECM carriers were tested with a novel in vitro assay to simulate the support of adherent cells for gene-modified cell therapy.

No description available.

Thesis (Ph. D.)--School of Biomedical Engineering, Georgia Institute of Technology, 2004. Directed by Timothy M. Wick. / Vita. Includes bibliographical references (leaves 182-195).

Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Biomedical Engineering. Title from title-page of electronic thesis. Bibliography: leaves 122-138.

Thesis (Ph.D.)--Drexel University, 2009. / Includes abstract and vita. Includes bibliographical references (leaves 160-177).

Zugl.: München, Techn. Universiẗat, Diss., 2009.

Thesis (M.S.)--New Jersey Institute of Technology, Dept. of Biomedical Engineering, 2003. / HFT20030804. Includes bibliographical references (p. 75-76). Also available via the World Wide Web.

published_or_final_version / Orthopaedics and Traumatology / Doctoral / Doctor of Philosophy

Formation of an intact, continuous and biological interface with proper zonal organization between mechanically dissimilar tissues is a key challenge in complex tissue engineering. The presence of a stable interface between soft and hard tissues is important. In particular, the presence of the osteochondral interface can prevent mechanical failure by reducing the shear stress across it. It also prevents vascularization and subsequent mineralization of the uncalcified cartilage, thus maintaining the normal tissue function. In this study, we demonstrated that with the use of mesenchymal stem cells, the collagen scaffold and the microencapsulation technology, an osteochondral interface with a zone of calcified cartilage could be generated in vitro in 5 weeks. Specifically, by placing an undifferentiated mesenchymal stem cell-collagen gel between an upper cartilage-like part and a lower bone-like part, cells in the middle layer were able to remodel the collagen gel into an interface similar to that found in vivo. Hypertrophic chondrocytes populated this in vitro generated interface, secreting GAGs, collagen type II and X, and calcium phosphates. Vertically running collagen fibers were found in this interface as well. We also demonstrated the importance of culture medium together with an appropriate configuration for interface formation. In particular, only with the use of both the chondrogenic medium and the three-layer configuration could we generate the osteochondral interface in vitro. Finally we conducted a pilot animal study on the efficacy of cartilage repair using constructs with a pre-formed osteochondral interface and demonstrated that cartilage re-surfacing was successful in only one month. Hyaline-like cartilage with a continuous tidemark was regenerated. This observed phenomenon could be maintained up to 3 months. Results of this study contribute to the development of better cartilage repair in future. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.