4D Biofabrication: Materials, Methods, and Applications.

The mission of regenerative medicine is the development of methods to regrow, repair, or replace damaged or diseased cells, organs, or tissues. 3D bioprinting techniques are one of the most promising approaches for engineering the design of artificial tissues. Current 3D bioprinting technologies possess, however, several intrinsic limitations. 4D biofabrication, a recently developed technology with the embedded ability of shape transformation upon response to intrinsic and/or external stimuli, may solve challenges of 3D bioprinting as well as more accurately mimic the dynamics of the native tissues. This article covers recent advances in 4D biofabrication. It gives a detailed picture of used materials and technologies, provides critical comparisons of methods, discusses possibilities and limitations of different 4D biofabrication technologies, and gives examples of applications.