Tissue engineering

Tissue engineering, scientific field concerned with the development of biological substitutes capable of replacing diseased or damaged tissue in humans. The term tissue engineering was introduced in the late 1980s. By the early 1990s the concept of applying engineering to the repair of biological tissue resulted in the rapid growth of tissue engineering as an interdisciplinary field with the potential to revolutionize important areas of medicine.

Tissue engineering integrates biological components, such as cells and growth factors, with engineering principles and synthetic materials. Substitute tissues can be produced by first seeding human cells onto scaffolds, which may be made from collagen or from a biodegradable polymer. The scaffolds are then incubated in mediums containing growth factors, which stimulate the cells to grow and divide. As cells spread across the scaffold, the substitute tissue is formed. This tissue can be implanted into the human body, with the implanted scaffold eventually being either absorbed or dissolved.

Examples of tissues that are candidates for tissue engineering include skin, cartilage, heart, and bone. The production of skin substitutes has played an important role in improving the success of skin graft surgeries, especially for complex wounds such as burns. Substitute tissues of the renal system, including urinary bladders and urethras, have also been engineered and transplanted successfully, thereby broadening therapeutic opportunities for complicated renal disorders. Scaffolds and bioartificial tissues are being investigated for their use in the development of functioning bioartificial limbs; the first such limb to be successfully developed—a rat leg with functioning muscles and veins—was reported in 2015.

bioartificial limbA bioartificial rat limb shown suspended in a bioreactor that contains a nutrient solution and electrical stimulation to support and promote the growth of new tissue.