4D bioprinting: smart materials, technologies and applications

The term “four dimensional (4D) printing” has been introduced to denote the fabrication via Additive Manufacturing technologies (commonly known as 3D printing) of structures with the capability to shape transform over time, the “fourth dimension”, under a predefined stimulus. Shape-changing, self-repairing, self-assembly, are some of the characteristics today associated with 4D printed structures, highlighting that these are no longer static objects but programmable active structures that accomplish their function through a change in their physical and/or chemical properties over time when exposed to a predetermined stimulus. The lesson will provide an overview of 4D printing, as an emerging and evolving technology in the biomedical field. After an introduction to smart materials, a design pipeline for 4D printing functional parts will be discussed. Relevant applications will be presented, including soft actuators, biosensors, scaffolds, drug delivery systems, and medical devices.