Multiscale 3D microfluidic platform for intraorganoid delivery

Neural organoids are emerging as advanced three-dimensional (3D) in vitro models for recapitulating human development and pathology, but they lack dedicated mass-transport pathways that perfuse interior regions, limiting control over solute concentrations in deep tissues. Microfluidic technologies hold promise for intra-organoid delivery, yet creating high-resolution 3D transport architectures spanning arteriole-to-venule scales while integrating them with minimal disruption to morphogenesis remains challenging. Here, we introduce a multiscale 3D microfluidic delivery platform that embeds lithographically defined, flexible, thread-like microchannels into organoids during growth. The nanoporous interface along the embedded microchannels enables controlled diffusive transport of biomolecules into localized regions with ~100 um spatial resolution and to depths of ~400 um from the organoid center, with minute-scale temporal precision, as demonstrated with dyes, morphogens, and MRI contrast agents. Delivery of growth factor–supplemented media leads to reduced apoptosis near the microchannels and improved neural tissue integrity. This platform offers a robust means to interrogate deep, site-specific microenvironments and to advance studies of organoid viability, structural organization, and functional maturation.