Biofabrication: Print your heart out

New drug development can take more than 10 years and only around 16% of drug candidates that begin pre-clinical testing are approved for human use. Some of this low success rate is due to the different responses of humans and the animal models currently used for testing. Parallel to the development of 3D printing and additive manufacturing techniques using polymers and metals another set of novel techniques have been developed which can print living biological cells. A key challenge has been the development of gentler printing processes to preserve cellular functions. By encapsulating cells inside a gel, complex 3D structures can be printed with cells suspended throughout the structure. The cells grow and multiply within the structure, creating their own matrix and forming tissues. Combining these new techniques which can 3D bioprint cells with the research generating organ-specific cells from pluripotent stem cells, it should be possible to bioprint 3D micro-tissues that replicate the response and functions of a human organ but on a much smaller scale. Such micro-tissues could be used to improve the efficiency of novel drug testing or alternatively could be implanted into a patient with a damaged organ.