Browsing by Author "Elizabeth Loboa, Committee Member"

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    Cellulose Nanocrystals Reinforced Electrospun Poly(lactic acid) Fibers as Potential Scaffold for Bone Tissure Engineering.
    (2010-04-29) Ramirez, Magaly Alexandra; Lucian Lucia, Committee Chair; Elizabeth Loboa, Committee Member; Orlando Rojas, Committee Member
    Poly(lactic acid) / Cellulose Nanocrystals (PLA / CNs) were simultaneously electrospun to fabricate a novel renewable and biocompatible nanocomposite as potential scaffold for bone tissue engineering. CNs were successfully incorporated into the PLA fibers to reinforce the electrospun fiber mat. Thermal, chemical and mechanical analyses were performed to characterize and determine the properties of the scaffold fabricated. Highly porous fibers with fibers diameters in the range of 500-1000 nm were characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Crystallinity of the electrospun nanocomposite was studied by Differential Scanning Calorimetry. Adipose-derived human mesenchymal stem cells (hMSCs) were used to study the cytocompatibility of the nanocomposite scaffold. Life/dead cell assay was performed to determine cell viability of the scaffolds. After one week of cell culture, confocal microscopy indicated that the cells grown on the PLA / CNs nanocomposite were confluent and very well aligned along the fibers while cells cultured on pure PLA fibers were not as confluent as in the developed nanocomposite. This project has demonstrated the feasibility of the fabricated PLA/CNs nanocomposite as a potential scaffold for bone tissue engineering.
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    Finite Element Analysis of an In Vitro Traumatic Joint Loading Model
    (2010-04-20) Shoge, Richard; Ola Harrysson, Committee Member; Elizabeth Loboa, Committee Member; Peter Mente, Committee Chair; Simon Roe, Committee Member; Mohammed Zikry, Committee Member
    Osteoarthritis (OA) is characterized by the degeneration of articular cartilage resulting in eventual bone on bone contact causing pain and inflammation to musculoskeletal joints. An in vitro impact injury model that incorporated tangential loading was developed in our lab using intact porcine patellae to produce quantifiable degradation similar to that seen in early stage osteoarthritis. We carried out two separate sets of in vitro impact experiments: (1) axial impactions: an impact insult normal to the cartilage surface at a high load and relatively fast loading rate and (2) shear impactions: a compressive preload normal to the surface subsequently followed by a tangentially applied displacement generating a shear load. Cell death and matrix proteoglycan loss were quantified. After validation of the finite element model and collection of histological data, statistical analysis was used to correlate type, location and magnitude of stress and strain with cell death and proteoglycan loss. The overall hypothesis was that shear forces arising from traumatic impact injuries are more detrimental to cartilage matrix and chondrocytes than axial forces normally seen in most impact injury models.