Crumbling the Wall: New Paradigms to Transform Biomaterials, Tissue Engineering, Healing and Regeneration
Michael L. and Myrna Darland Endowed Chair
in Technology Commercialization University of Washington
The winner of the 2008 Pritzker Distinguished Lectureship Buddy D. Ratner, presented a plenary lecture at the annual Biomedical Engineering Society (BMES) meeting.
Biomaterials have impacted millions of people, saving lives and improving the quality of life. Biomaterials have directly spawned the field we call tissue engineering by evolving the technologies for polymeric scaffolds, gels, controlled release systems, cell culture surfaces, etc. The concept of “living parts” that grow with the patient, repair themselves, fight infection, and exhibit the elegant control and functionality associated with the original biological part is certainly attractive. How can we best achieve fully functional tissue engineering that will transform medicine?
Tissue engineering is closely allied with terms such as healing, integration, inflammation, reconstruction, and regeneration. Often, these processes are inhibited in adult humans. Shortly after birth, healing goes from a regenerative, reconstructive process to a response that Professor Stephen Badylak refers to as “the default mechanism of healing,” i.e., avascular scarring. An analogous process is noted in the response of the body to implanted “biocompatible materials.” Within three weeks, the “biocompatible” implant is encapsulated in a tough, avascular, collagenous (fibrotic) bag. On the other hand, tissue engineered constructs on scaffolds that are pre-seeded with cells and conditioned in a bioreactor can often be implanted with little or no fibrotic reaction and some vascularization. Also, some decellularized tissues can be reimplanted with a reconstructive, rather than a fibrotic outcome. Finally, a new class of materials developed at the University of Washington, sphere templated scaffolds, can be implanted with remarkable tissue reconstruction and little fibrotic reaction. The commonality in these examples of reconstructive healing, in contrast to fibrotic healing, may be a “taming” of the macrophage. The macrophage is essential to healing and reconstruction, but if triggered incorrectly may lead to the destructive process often called chronic inflammation. This talk focused on strategies to guide the macrophage down a reconstructive pathway. The outcomes anticipated by pursuing this approach will be well integrated biomaterials (for example, long term implanted bioelectrodes), a new definition of biocompatibility and enhanced tissue engineering.
His research interests include biomaterials, tissue engineering, polymers, biocompatibility, surface analysis of organic materials, self assembly, nanobiotechnology, and RF-plasma thin film deposition.
Buddy D. Ratner is the director of University of Washington Engineered Biomaterials Engineering Research Center and the Michael L. and Myrna Darland Endowed Chair in Technology Commercialization. He is professor of bioengineering and chemical engineering at the University of Washington.