Additive manufacturing has attracted a lot of attention in fabrication of bio medical devices and structures in recent years. 4D printing, a new class of 3D printing where time is considered as a 4th dimension, allows us to build biological structures such as scaffolds, implants, and stents with dynamic performance mimicking the body's natural tissues. In order to properly exploit the capabilities of this fabrication method, understanding and exploiting the shape memory materials is critical. These 'smart' materials are responsive to the external stimuli which eliminates the need for utilizing the sensors, and batteries. These stimuli-triggered 'smart' materials possess a dynamic behavior unlike the static scaffolds based on conventional manufacturing techniques. In this review, recent advances on application of 4D printing for manufacturing of this type of materials and other high-performance biomaterials for medical applications have been discussed.
Keywords: 3D printing; 4D printing; Additive manufacturing; smart materials; tissue engineering.