Cell-interactive polymers for tissue engineering

Abstract

Every year, millions of patients suffer the loss or failure of an organ or tissue as a result of accidents or disease. Over 8 million surgical procedures are performed to treat these patients in US each year, and the overall cost of these problems to the US economy is estimated to exceed $400 billion per year. Tissue or organ transplantation is a generally accepted therapy to treat these patients. However, this approach is extremely limited by a donor shortage. For example, according to the American Heart Association, only 2300 people received a heart transplant in 1997, while approximately 40,000 patients in the US alone could benefit from this therapy. Tissue engineering is one recent approach to treat patients who need a new organ or tissue with man-made organs or tissues. In this approach, tissues are engineered using a combination of a patient`s own cells and polymer scaffolds. Tissue-specific cells are isolated from a small biopsy from the patient and expanded in vitro. The cells are subsequently incorporated into three-dimensionally designed polymer scaffolds. In this approach, the polymer potentially mimics many roles of natural extracellular matrices, which bring cells together and control the tissue structure, regulate the function of the cells, and allow the diffusion of nutrients, metabolites, and soluble factors. Many tissues, including skin, artery, bladder, cartilage, and bone, are being engineered using this approach, and several of them are at or near clinical uses. One critical element in this tissue engineering approach is the regulation of interactions between cells and polymer scaffolds. The interactions can be regulated by controlling specific ligand-receptor interactions, physical properties of the scaffolds (e.g., mechanical properties and degradation rate), and the release of soluble factors (i.e., growth factor and DNA) from the scaffolds. A variety of polymers have been studied and utilized to date in tissue engineering approaches. However, no single polymer has been considered ideal for all tissues and approaches. In this talk, design parameters of cell-interactive polymeric materials, potentially useful in tissue engineering applications, will be discussed.