Browsing by Author "Kelly, Cambre"
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Item Open Access Characterization of High Strength, High Porosity Gyroid-sheet Scaffolds(2020) Kelly, CambreAdditive manufacturing (AM, or 3D printing) has revolutionized fabrication of three dimensional (3D) parts with increased control over design at macro/meso-scale (part scale geometry, porous topology) and micro/nanoscale (topography). AM has enabled fabrication of metallic, polymeric, and ceramic scaffolds with complex porous architectures which were not previously achievable with traditional manufacturing methods. In particular, selective laser melting (SLM) has emerged as a leading technology for fabrication of porous metallic scaffolds for biomedical and other applications. Titanium alloy (Ti6Al4V) scaffolds are of interest due to the material’s high strength, corrosion resistance, and biocompatibility. Architecting porous scaffolds with tunable properties is highly relevant for load-bearing medical implants, including treatment of bone defects. Although established relationships exist for metallic foams, the complex topologies enabled by AM necessitate further characterization. In particular, investigation of processing-structure-property relationships for novel sheet-based architectures produced via SLM where topology strongly influences performance. Thus, the overall objective of this work is to develop fundamental topology driven processing-structure-property relationships considering tradeoffs between strength, fatigue resistance, and osseointegrative behavior of SLM titanium scaffolds.
Item Open Access Effect of surface topography on in vitro osteoblast function and mechanical performance of 3D printed titanium.(Journal of biomedical materials research. Part A, 2021-10) Abar, Bijan; Kelly, Cambre; Pham, Anh; Allen, Nicholas; Barber, Helena; Kelly, Alexander; Mirando, Anthony J; Hilton, Matthew J; Gall, Ken; Adams, Samuel BCritical-sized defects remain a significant challenge in orthopaedics. 3D printed scaffolds are a promising treatment but are still limited due to inconsistent osseous integration. The goal of the study is to understand how changing the surface roughness of 3D printed titanium either by surface treatment or artificially printing rough topography impacts the mechanical and biological properties of 3D printed titanium. Titanium tensile samples and discs were printed via laser powder bed fusion. Roughness was manipulated by post-processing printed samples or by directly printing rough features. Experimental groups in order of increasing surface roughness were Polished, Blasted, As Built, Sprouts, and Rough Sprouts. Tensile behavior of samples showed reduced strength with increasing surface roughness. MC3T3 pre-osteoblasts were seeded on discs and analyzed for cellular proliferation, differentiation, and matrix deposition at 0, 2, and 4 weeks. Printing roughness diminished mechanical properties such as tensile strength and ductility without clear benefit to cell growth. Roughness features were printed on mesoscale, unlike samples in literature in which roughness on microscale demonstrated an increase in cell activity. The data suggest that printing artificial roughness on titanium scaffold is not an effective strategy to promote osseous integration.