Special Collection: Emerging Concepts in Three-Dimensional Microtissues

Over the past decade, the concept of tissue engineering has been extended to include technologies that use multicellular aggregates, not only to repair or replace tissue but also as a stand-alone in vitro device (e.g., organ-on-a-chip) with well-defined biological outputs. The advantage of such systems is that they allow for culture of one or more cell types in three dimensions, which may promote tissue function that is more mimetic of the in vivo state, while allowing high-throughput sample testing and a large degree of control of external culture factors that may lead to more reproducible results than that found in the more complex in vivo environment. While the means used to achieve these devices vary greatly, in this special collection, we focus our attention on formation and use of scaffold-free cellular aggregates (three-dimensional microtissues).