UC San Diego

Biodegradable polymers have been commonly implemented in controlled drug release, tissue engineering scaffolds, and short term prosthesis. The engineering of these biomaterials for their specific applications is crucial for the control of their mechanical and dissolution properties. The proper optimization of polycaprolactone for medical use requires development of a robust fabrication technique, analysis of mechanical and dissolution properties in a specific environment, and analysis of diffusion through the material. The thesis presents a novel technique for fabrication of complex geometry structures with polycaprolactone which allows for varying layers of porosity within the structure. Polycaprolactone sheets of 125 microns, 250 microns, and 500 microns are fabricated and molded to create the complex elliptical geometry of the shunt cuff. The research further studies the effects of cyclic loading on the dissolution of porous polycaprolatone, revealing drastic decrease in dissolution time as well an altered dissolution profile under cyclic loading. A model for the effect of pore diameter, porosity, and section thickness on blood flow rate through the porous material due to dynamic blood pressure is developed. The fabrication technique and the dissolution properties of polycaprolactone can be engineered to create a bioabsorbable shunt cuff that satisfies the needed dissolution and strength properties required for application in a shunt cuff.