18. Tissue Engineering and Regenerative Medicine

Biomaterials and biomedical devices can be constructed of a variety of materials, and depending on the end use, incorporation of bioactive species such as drugs, enzymes, growth factors, and other molecules is possible. Until the last 15 years, a complete biological entity such as a cell was not incorporated into the biomedical devices. Most of these devices were generally expected and designed to be stable, to have service lives long enough to serve as long as the host lived, except for a few cases such as resorbable sutures and short-duration implants. However, the thought of biodegradable cell-seeded devices that would completely integrate with the biological system during the wound healing process was very appealing because these implants were to be designed to blend with the tissues in the body, and this would be a cure and would not leave behind any traces after a certain implantation period. As a result of these important advantages, this approach became a very appealing solution for many problems arising from the long-term implantation of durable materials. This new field, now called “tissue engineering,” is supported by a number of interdisciplinary fields (Fig. 18.1). The main components of tissue engineering are a scaffold or a cell carrier, mature or stem cells, and bioactive molecules such as growth factors (Fig. 18.2). Meanwhile cell therapies were introduced into the field of novel therapeutic tools where the main difference from tissue engineering was the absence of the scaffold. Over time these two fields together started to be called regenerative medicine.