Scholarly Works, School of Biomedical Engineering and Sciences
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Browsing Scholarly Works, School of Biomedical Engineering and Sciences by Department "Materials Science and Engineering (MSE)"
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- Fabrication and Characterization of Three Dimensional Electrospun Cortical Bone ScaffoldsAndric, Tea; Taylor, Brittany L.; Degen, Katherine E.; Whittington, Abby R.; Freeman, Joseph W. (De Gruyter Open, 2014)Bone is a composite tissue composed of an organic matrix, inorganic mineral matrix and water. Structurally, bone is organized into two distinct types: trabecular (or cancellous) and cortical (or compact) bone. Cortical bone is highly organized, dense and composed of tightly packed units or osteons whereas trabecular bone is highly porous and usually found within the confines of cortical bone. Osteons, the subunits of cortical bone, consist of concentric layers of mineralized collagen fibers. While many scaffold fabrication techniques have sought to replicate the structure and organization of trabecular bone, very little research focuses on mimicking the organization of native cortical bone. In this study we fabricated three-dimensional electrospun cortical scaffolds by heat sintering individual osteon-like scaffolds. The scaffolds contained a system of channels running parallel to the length of the scaffolds, as found naturally in the haversian systems of bone tissue. The purpose of the studies discussed in this paper was to develop a mechanically enhanced biomimetic electrospun cortical scaffold. To that end we investigated the appropriate mineralization and cross-linking methods for these structures and to evaluate the mechanical properties of scaffolds with varying fiber angles. Cross-linking the gelatin in the scaffolds prior to the mineralization of the scaffolds proved to help prevent channels of the osteons from collapsing during fabrication. Premineralization, before larger scaffold formation and mineralization, increased mineral deposition between the electrospun layers of the scaffolds. A combination of cross-linking and premineralization significantly increased the compressive moduli of the individual scaffolds. Furthermore, scaffolds with fibers orientation ranging between 15° and 45° yielded the highest compressive moduli and yield strength.
- Microporous bacterial cellulose as a potential scaffold for bone regenerationZabrowska, Magdalena; Bodin, Aase; Bäckdahl, Henrik; Popp, Jenni; Goldstein, Aaron; Gatenholm, Paul (2010-01)Nanoporous cellulose biosynthesized by bacteria is an attractive biomaterial scaffold for tissue engineering due to its biocompatibility and good mechanical properties. However, for bone applications a microscopic pore structure is needed to facilitate osteoblast ingrowth and formation of a mineralized tissue. Therefore, in this study microporous bacterial cellulose (BC) scaffolds were prepared by incorporating 300–500 lm paraffin wax microspheres into the fermentation process. The paraffin wax microspheres were subsequently removed, and scanning electron microscopy confirmed a microporous surface of the scaffolds while Fourier transform infrared spectroscopy verified the elimination of paraffin and tensile measurements showed a Young’s modulus of approximately 1.6 MPa. Microporous BC and nanoporous (control) BC scaffolds were seeded with MC3T3-E1 osteoprogenitor cells, and examined by confocal microscopy and histology for cell distribution and mineral deposition. Cells clustered within the pores of microporous BC, and formed denser mineral deposits than cells grown on control BC surfaces. This work shows that microporous BC is a promising biomaterial for bone tissue engineering applications.