Rapid prototyping technologies for tissue regeneration

: Tissue engineering and regenerative medicine hold a great promise for restoring functional tissues and organs and yet is still limited by its inability to reproduce macro- and micro-structures of native tissues and organs. The limitation may be overcome by fully mimicking those structures with computer-aided design (CAD) and fabrication. To date, rapid prototyping technologies with layer-by-layer construction provide a very powerful tool to fabricate intricate 3D scaffold and/or cell/tissue constructs with precisely controlled macro- and micro-features. Moreover, fine features, needed to surpass the oxygen diffusion problem at 100–200 μm, can be easily achieved with rapid prototyping technologies compared to traditional scaffold fabrication approaches. Over the last two decades, more than 20 rapid prototyping devices have been developed and used in laboratories for biomedical applications. In this review, these devices are categorized into laser-assisted based, extrusion or dispensing-based, and inkjet-based rapid prototyping technologies. Depending on specific technologies and types of materials used, rapid prototyping technologies may be used in engineering hard and soft tissues or even whole organs. These applications will be discussed along with their advantages, shortcomings, and future trends.