That is significant, considering cartilage does not grow back on it own. For tendons, biodegradable surgical sutures are placed in a pencil-shaped mold where the cells essentially suck the water out of the gel, stick to each other and form tight bonds around the suture. When these are sewn onto a severed tendon, they grow into new tendons. All of this is possible because of decades of basic research on cell communication and migration, says Kyriacos Zygourakis of Rice University. As the cells divide and differentiate in a developing embryo, they need to move to specific places to make nerves and heart tissue and lungs and skin.
Early development is a very active period when cell migration is the name of the game.
Knowledge gained from developmental research and studies of cancer metastasis, where cancer cells learn to spread to different tissues of the body, provides tremendous insight for tissue engineers who must get their cells not only to multiply but also to move and make room for new cells as they colonize. Cells communicate chemically with each other and respond to chemical cues from their environment. The cues important to tissue engineers are those that tell cells to divide, migrate and differentiate into tissue, Zygourakis says. Natural substances called growth factors contain cues for getting cells to multiply and to migrate. Substances called adhesive peptides hold the cues to encourage cells to stick to and colonize the scaffolding materials that are used to deliver the cells.