4-dimensional printing (4D printing; also known as 4D bioprinting, active origami, or shape-morphing systems) uses the same techniques of 3D printing through computer-programmed deposition of material in successive layers to create a three-dimensional object. However, 4D printing adds the dimension of transformation over time. It is therefore a type of programmable matter, wherein after the fabrication process, the printed product reacts with parameters within the environment (humidity, temperature, etc.,) and changes its form accordingly. The ability to do so arises from the near infinite configurations at a micrometer resolution, creating solids with engineered molecular spatial distributions and thus allowing unprecedented multifunctional performance. 4D printing is a relatively new advance in biofabrication technology, rapidly emerging as a new paradigm in disciplines such as bioengineering, materials science, chemistry, and computer sciences.