Doctors use a combination of cells and bioengineered materials to restore, maintain, improve, or replace damaged tissue. Called tissue engineering, this process of restoring, maintaining, improving, and/or replacing damaged tissues and organs looks to create functional human tissues or organs in a laboratory before they are placed back into the human body.

Tissue engineering uses a combination of three key components: scaffolds, cells, and biomedical materials.

Tissue engineering often begins with a scaffold, which may utilize any of a number of potential materials from naturally occurring proteins to biocompatible synthetic polymers, to provide the structural support for cell attachment and subsequent tissue growth. 

Certain tissue engineering therapies may use an existing scaffold by removing cells from a donor organ, a process called decellularization, until only the pre-existing protein-based scaffold or extracellular matrix (ECM) remains. Cells —and in some cases, additional growth factors to encourage the cells to take root— are added, allowing a tissue or organ to develop and grow ex-vivo.

Biomaterials, which include any substance engineered to interact with a patient’s living biological system for a medical purpose, often provide support as the physical structure for engineered tissues.

Researchers have successfully engineered bladders, small arteries, skin grafts, cartilage and a full trachea.