"A Direct-Write Three-Dimensional BioAssembly Tool for Regenerative Medicine "
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Abstract: Tissue loss and end-stage organ failure caused by disease or injury are two of the most costly problems encountered in modern medicine. To combat these problems, a relatively new field, called tissue engineering, has emerged. This field combines the medical and engineering fields in hopes of establishing an effective method to restore, maintain, or improve damaged tissue. In order to best replace the diseased tissue, many approaches to fabricating new tissue have focused on trying to replicate native tissue. The overall hypothesis of this dissertation is that a direct-write, BioAssembly Tool (BAT) can be utilized to fabricate viable constructs of cells and matrix that have a specified spatial organization and are truly three-dimensional (3D). The results of the studies within this dissertation demonstrate that the BAT can generate viable, spatially organized constructs comprised of cells and matrix by carefully controlling the environmental parameters of the system. A joint hypothesis associated with this dissertation is that 3D microscopy and image processing techniques can be combined to generate accurate representative stacks of images of the tissue within 3D, tissue engineered constructs. The results of the studies examining this hypothesis demonstrate that by taking into account the attenuation with depth in the imaged construct as well as by looking at the intensity and gradient of each voxel, accurate and reproducible thresholding can be achieved. Furthermore, this tool can be utilized to aid in the characterization of 3D tissue engineered constructs. Based on these studies, 3D microscopy and image processing shows promise in accurately representing the cellular volume within a tissue. More importantly, 3D, direct-write technology, specifically the BioAssembly Tool, could be used in the fabrication of viable, spatially organized constructs that can then be implanted into a patient to provide healthy tissue in the place of diseased or damaged tissue.