Probing the role of multicellular organization in three-dimensional microenvironments.

Successful application of living cells in regenerative medicine requires an understanding of how tissue structure relates to organ function. There is growing evidence that presentation of extracellular cues in a three-dimensional (3D) context can fundamentally alter cellular responses. Thus, microenvironment studies that previously were limited to adherent two-dimensional (2D) cultures may not be appropriate for many cell types. Here we present a method for the rapid formation of reproducible, high-resolution 3D cellular structures within a photopolymerizable hydrogel using dielectrophoretic forces. We demonstrate the parallel formation of >20,000 cell clusters of precise size and shape within a thin 2-cm(2) hydrogel and the maintenance of high cell viability and differentiated cell markers over 2 weeks. By modulating cell-cell interactions in 3D clusters, we present the first evidence that microscale tissue organization regulates bovine articular chondrocyte biosynthesis. This platform permits investigation of tissue architecture in other multicellular processes, from embryogenesis to regeneration to tumorigenesis.