POLYMER CONCEPTS IN TISSUE ENGINEERING

Traumatic injuries, cancer treatment, and congenital abnormalities are often associated with abnormal bone shape or segmental bone loss. Res toration of normal structure and function in these cases requires repl acement of the missing bone that may be accomplished by surgical trans fer of natural tissue from an uninjured location elsewhere in the body . However, this procedure is limited by availability, adequate blood s upply, and secondary deformities at the donor site. One strategy to ov ercome these problems is to develop living tissue substitutes based on synthetic biodegradable polymers. Three methods of bone regeneration using biodegradable polymers are being studied in our laboratory: tiss ue induction, cell transplantation, and fabrication of vascularized bo ne flaps. Injectable polymers are used for filling skeletal defects an d guiding bone tissue growth. Their main advantage is minimizing the s urgical intervention or the severity of the surgery. Polymer-cell cons tructs also hold great promise in the field of tissue engineering. The y provide a scaffold on which cells grow and organize themselves. As t he cells begin to secrete their own extracellular matrix, the polymer degrades and is eventually eliminated from the body, resulting in comp letely natural tissue replacement. Bone flaps can be fabricated ectopi cally into precise shapes and sizes. With an attached vascular supply, these flaps can be transferred into areas deficient in vascularity. T his article discusses polymer concepts regarding bone tissue engineeri ng and reviews recent advances of our laboratory on guided bone regene ration using biodegradable polymer scaffolds. (C) 1998 John Wiley & So ns, Inc.Traumatic injuries, cancer treatment, and congenital abnormali ties are often associated with abnormal bone shape or segmental bone l oss. Restoration of normal structure and function in these cases requi res replacement of the missing bone that may be accomplished by surgic al transfer of natural tissue from an uninjured location elsewhere in the body. However, this procedure is limited by availability, adequate blood supply, and secondary deformities at the donor site. One strate gy to overcome these problems is to develop living tissue substitutes based on synthetic biodegradable polymers. Three methods of bone regen eration using biodegradable polymers are being studied in our laborato ry: tissue induction, cell transplantation, and fabrication of vascula rized bone flaps. Injectable polymers are used for filling skeletal de fects and guiding bone tissue growth. Their main advantage is minimizi ng the surgical intervention or the severity of the surgery. Polymer-c ell constructs also hold great promise in the field of tissue engineer ing. They provide a scaffold on which cells grow and organize themselv es. As the cells begin to secrete their own extracellular matrix, the polymer degrades and is eventually eliminated from the body, resulting in completely natural tissue replacement. Bone flaps can be fabricate d ectopically into precise shapes and sizes. With an attached vascular supply, these flaps can be transferred into areas deficient in vascul arity. This article discusses polymer concepts regarding bone tissue e ngineering and reviews recent advances of our laboratory on guided bon e regeneration using biodegradable polymer scaffolds. (C) 1998 John Wi ley & Sons, Inc.