Identifier

etd-01202011-204235

Degree

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

Document Type

Thesis

Abstract

Historically, bone repair has been performed using materials like metals, ceramics, cements and bioactive glass. The major problem with all these materials is that they do not perform the necessary non-structural functions of bone. Engineered tissue, created by growing bone cells on porous biodegradable material (scaffold), will address this issue with current bone repair techniques. Improving engineered tissue treatments requires a thorough understanding of factors affecting cell seeding and proliferation inside a disordered porous material which is not feasible using current experimental techniques. A model for particle transport in a disordered porous material that can predict the particle deposition pattern will be useful to understand the factors influencing particle transport and retention. Such a model has applications ranging from biomedical, microfluidics, environmental and water treatment. Currently available models for filtration or contaminant transport in a porous media either consider the porous media to be uniform or do not predict the particle deposition pattern. We develop an image-based computational model, which incorporates the structure of a disordered porous material, to study the effect of flow and material internal structure on particle transport and deposition, which was then applied to cell seeding. Particle motion and attachment inside the porous material is controlled by a deterministic convection component, obtained by numerically solving the Stokes Equation using FEM; a stochastic diffusion component, modeled using a random walk process, and an electrostatic component estimated using analytical expressions for the interaction of a colloid particle with a surface. Our simulations show that the Peclet number has a significant effect on the cell attachment pattern in a scaffold. At low Peclet numbers, cell attachment is concentrated at the inlet region of the scaffold, while cells penetrate deeper into the scaffold with increasing Peclet number. Additionally, the seeding pattern is found to vary considerably with internal pore structure. Visualization of the data indicates that attachment clusters at low velocity diffusion dominated zones.

Date

2011

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Henry, James E.

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