OrgDense: An automatic microfluidic centrifugal device for 3D cell condensation.

Stem cell-derived organoid development typically involves an initial gel-free embryoid body (EB) formation step followed by a gel-embedded differentiation phase. Although high-throughput EB formation technologies are well established, the manual gel-embedding step remains a major bottleneck that limits overall throughput. In this study, we introduce OrgDense, a droplet-confined high-throughput centrifugal cell condensation method that operates within nanoliter volumes. OrgDense efficiently aggregates stem cells into compact cell pellets within a gel matrix, processing over 1000 organoid precursors per batch. The cell-occupied projected area was reduced to ∼50% of that in controls, thus enhancing paracrine signaling. Condensed droplet-engineered organoids reliably developed into organoids from single colonies with accelerated developmental timelines. In gel-free conditions, OrgDense enabled rapid cell aggregation within 1 h without compromising cell viability. Moreover, centrifuge-based condensation demonstrated robust compatibility across multiple cell lines and primary cells.