Microscale tissue engineering using gravity-enforced cell assembly

Designing artificial microtissues by reaggregation of monodispersed primary cells, neoplastic or engineered cell lines is providing insight into cell–cell interactions and underlying regulatory networks. Recent advances in microtissue production have highlighted the potential of scaffold-free cell aggregates in maintaining tissue-specific functionality, supporting seamless integration of implants into host tissues, and providing complex feeder structures for difficult-to-differentiate cell types. Furthermore, these tissues are amenable to therapeutic and phenotype-modulating interventions using latest-generation transduction technologies. Microtissues produce therapeutic transgenes at increased levels and offer tissue-like assay environments to improve drug-function correlations in current discovery programs. Here, we outline scaffold-free microtissue design in liver, heart and cartilage, and discuss how this technology could significantly impact regenerative medicine.