Seminar 3/9: Design and Development of Poly(ester urethane)urea Biomaterials for Treatment of Orthopaedic Injuries

Department of Chemical Engineering
West Virginia University

Seminar

Design and Development of Poly(ester urethane)urea Biomaterials for Treatment of Orthopaedic Injuries

Dr. Scott Guelcher
Assistant Professor
Chemical Engineering Dept.
Vanderbilt University
VU Station B Box 351604
Nashville, TN 37235-1604

ABSTRACT

Within the US an estimated 643,000 grafting procedures were performed in 2002, thus making bone the second most transplanted tissue after blood. Although autologous bone graft has the best capacity to stimulate healing of tissue defects, explantation risks donor-site morbidity. Polyurethanes, a commercially significant class of synthetic polymers, possess important and in some ways unique attributes that render them potentially useful alternatives to bone grafts. By controlling the composition, structure, and processing conditions, we seek to create a family of new polyurethane biomaterials having targeted biological and mechanical properties for treatment of orthopaedic clinical indications. The following projects currently under investigation contribute to achieving this goal.

Injectable polyurethane scaffolds for drug and gene delivery. The development of therapeutics exploiting minimally invasive surgical techniques has substantial benefits for treatment of orthopaedic clinical indications, such as vertebral compression fractures. Polyurethane foams prepared from two reactive liquid components which harden in situ comprise a potentially injectable delivery system. Biodegradable polyurethane foams have been synthesized from lysine-derived and aliphatic polyisocyanates, polyester triols, water, and non-cyto toxic additives designed to control the reactivity and surface chemistry of the reactive liquid mixture. These materials cure in 5 – 20 minutes and support ingrowth of new tissue in vivo. Considering these desirable properties, polyurethane foams are being investigated as injectable delivery systems for treatment of orthopaedic clinical indications.

Polyurethane scaffolds for ex vivo bone tissue engineering. Degradable scaffolds designed to stimulate healing through the natural tissue remodeling process are promising alternatives to bone graft. The modulus of the scaffold is hypothesized to affect the development of bone tissue ex vivo. Segmented polyurethane elastomers, comprising alternating hard and soft blocks, are ideal materials to test this hypothesis because the structure can be systematically varied to control the properties. A family of segmented polyurethane elastomers has been prepared from aliphatic diisocyanates, novel tyramine-based chain extenders, and polyester macrodiol soft segments. Porous scaffolds have been prepared from segmented polyurethanes in collaboration with researchers at Virginia Tech using a solvent casting/compression molding process. In future studies, BMSCs will be cultured in polyurethane scaffolds using novel perfusion strategies to engineer scaffolds that stimulate healing in vivo by directing osteoblastic maturation and synthesis of bioactive factors.

Friday, March 9, 2007 9:30am - 10:45am
Room 401, Engineering Sciences Building
Refreshments will be served at 9:15 am

Questions or Directions call: 304-293-2111, ext. 2418.

03/09/2007