Master's Thesis Defense - Gradient Porous Structure (GPS) Plastics for Tissue Engineering & Orthopedics
Date: June 10, 2011
Time: 2:00 PM
Location: Bossone Research Enterprise Center, Room: 630-A
Sean M. Devlin
Advisors: Peter I. Lelkes, Ph.D., Fred D. Allen, Ph.D., Jack G. Zhou, Ph.D., and David Wootton, Ph.D.
Gradient Porous Structures are biologically important features of many tissues that provide mechanical strength paired with porosity. In order to design the manufacturing process for a new class of porous polymer composite tissue scaffolds as surgical fixation devices, we have mathematically correlated morphological changes (such as pore size and distribution) within the polymers to manufacturing parameters such as time and temperature. The material consists of a porous, highly interconnected phase of biodegradable polymer formed from a co-continuous blend of the desired polymer and a sacrificial polymer that has been dissolved away after the controlled phase separation process which hones the morphology. Since early prototypes produced an erratic range of mechanical strengths, in silico modeling was proposed to correlate the variety of phase separation parameters that would otherwise be cost prohibitive to physically test. Two dimensional (2D) and three dimensional (3D) modeling techniques were explored using the Finite Element Method (FEM) applied to the Level Set Method for tracking moving fluid interfaces in laminar creeping flow, from which empirical correlations were drawn to aid in the manufacture of gradient porous surgical fixation devices.
Our analysis defines a novel correlation between structure and manufacturing parameters, suggesting that the resultant the pore size growth rate is equal to the ratio of the interfacial surface tension over the difference in fluid viscosities. These correlations allow for the rational design of surgical fixation devices with tunable gradient porous structures and mechanical properties.
The Bossone Research Enterprise Center is located at the corner of 32nd and Market Streets.