Current Research

Robert Sah's research focuses on the biomechanical function and failure of articular cartilage in joints and on the development of biological restoration therapies. His HHMI project included a collaborative research program in which undergraduates work with graduate students, medical students, postdoctoral fellows, and academic and industry researchers to study, fabricate, and test cartilage and biological joints. New courses and instructional materials in regenerative medicine were developed for undergraduates as well as K-12 students.

Project Summary
Regeneration research on biological joints has reached the stage where major breakthroughs in scientific understanding and in clinical therapies are emerging. This project integrated undergraduate research and education in regenerative medicine by studying, fabricating, and testing biological joints. One part of the project was to accelerate research on joints through the increased involvement of undergraduates in tiered interdisciplinary teams. Undergraduates at all levels, from freshmen to seniors, joined project-specific research teams. These undergraduates teamed with graduate students, medical students, residents, fellows, postdoctoral researchers, academic scientists, and industrial collaborators. Medical school faculty will include those from orthopedic surgery, head and neck surgery, rheumatology, and radiology. Basic scientists and engineers provided biomechanical, biotransport, and metabolic systems views of joints. Collaborating companies have a range of interests, from biomedical devices to biotechnologies.

The second part of the project was to enhance undergraduate education in tissue engineering and regenerative medicine by developing new instructional material and courses. Instructional modules on regeneration concepts and applications were formulated with examples from joint regeneration research. New courses were developed to introduce undergraduates to research, to provide students with practical laboratory tools for tissue engineering, and to integrate research needs into senior design projects.

The final part of the project was to increase the awareness of joint bioengineering in the community. K-12 students and teachers were engaged through field trips and hands-on bench experiences. Students in grades 9-12 were offered a summer course on joint bioengineering, and some of these students were then invited to continue as laboratory interns. An exhibit on biological joints and their restoration was developed and displayed.

Research Summary
Our research focuses on understanding the composition, structure, and biomechanical function of cartilage during growth, aging, and on the treatment of cartilage disease and injury through cartilage repair and replacement. We introduced biomechanical testing of cartilage with video microscopy, and used this technique to delineate the depth-varying compressive properties of cartilage. We also delineated how biomechanical and biochemical regulation of matrix metabolism affects cartilage structure and biomechanical function. These studies have provided insight into natural growth and disease pathogenesis, as well as tools for fabricating cartilage and joint tissues. A related area of research is joint lubrication mechanobiology; here, we have successfully grown cartilage tissue in the lab that has natural lubricant-secreting cells at the surface. We have also used biomimetic bioreactors to facilitate de novogrowth and maintenance of cartilaginous tissue, ranging from patches for focal cartilage defects to cartilage-covered joints. Our in vivostudies with cell tracers have delineated interactions between host and implanted cells in cartilage defect repair. The ultimate scientific and engineering goal is to enable bio-arthroplasty of arthritic joints.

Last updated September 2006

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