Tissue engineering is an exciting new field at the interface of engineering and - ology that uses implanted cells, scaffolds, DNA, proteins, protein fragments, and inductive molecules to repair or replace injured or diseased tissues and organs. Tremendous progress in biological and biomaterial aspects of this field have been accomplished to date, and several engineered tissues are now being used clinically. However, tissue engineers face major challenges in repairing or repl- ing tissues that serve a predominantly biomechanical function. To meet this challenge, the United States National Committee on Biomech- ics in 1998 adopted a new paradigm termed functional tissue engineering (FTE) to emphasize the importance of biomechanical considerations in the design and - velopment of cell and matrix-based implants for soft and hard tissue repair. Functional tissue engineering represents a relevant and exciting new discipline in the field of tissue engineering. Since many tissues, such as those of the muscu- skeletal, cardiovascular, and dental systems, are accustomed to being mecha- cally challenged, tissue-engineered constructs used to replace these tissues after injury or disease must certainly do the same. Of course, tissue engineers must also attempt to return normal biological activity in order for the construct to truly - tegrate with the surrounding tissues. Thus, the term functional can have many meanings, such as restoration of metabolic function. The primary focus of this text is on the role of biomechanical function in tissue engineering.
The goal of "tissue engineering" is to repair or replace tissues and organs by delivering implanted cells, scaffolds, DNA, proteins, and/or protein fragments at surgery. Tissue engineering merges aspects of engineering and biology, and many rapid achievements in this field have arisen in part from significant advances in cell and molecular biology.
Despite its early successes, however, tissue engineers have faced challenges in repairing or replacing tissues that serve a predominantly biomechanical function. This book addresses and discusses a number of issues that need to be addressed in order for tissue engineers to effectively repair or replace these load-bearing structures. What are the thresholds of force, stress, and strain that normal tissues transmit or encounter? What are the mechanical properties of these tissues when subjected to expected in vivo stresses and strains, as well as under failure conditions? Which of these properties should a tissue engineer insist upon incorporating into the design? Do tissue engineered repairs and replacements need to exactly duplicate the structure and function of the normal tissue or organ in order to be successful? When developing these implants in culture, how do physical factors such as mechanical stress regulate cell behavior in bioreactors as compared to signals experienced in vivo? And finally, can tissue engineers mechanically stimulate these implants before surgery to produce a better repair outcome?
Chapters written by well-known researchers discuss these matters and provide guidelines and a summary of the current state of technology in functional tissue engineering. The book will be useful to students and researchers as it will increase awareness among tissue engineers of the importance of restoring "function" when engineering tissue constructs, and identifying the critical structural and mechanical requirements needed for each construct. It will also providean invaluable source of information to help tissue engineers incorporate these functional criteria into the design, manufacture, and optimization of tissue engineered products. Finally it serves as a reference and teaching text for the rapidly increasing population of students and investigators in the field of tissue engineering.
