Abstract

Bone Marrow-on-a-Chip: Long-Term Culture of Human Hematopoietic Stem Cells in a 3D-Microfluidic Environment

Mark Rosowski, , Technical University of Berlin

Multipotent hematopoietic stem cells (HSCs) give rise to all blood cell types. The bone marrow stem cell niche in which the HSCs are maintained is known to be vital for their sustainment. Unfortunately, to this date, no in vitro model exists that truthfully mimics the aspects of the bone marrow niche and simultaneously allows the long-term culture of HSCs. In this study, we present a novel 3D co-culture model, based on a hydroxyapatite-coated zirconium oxide scaffold mimicking the trabecular bone. Primary human mesenchymal stromal cells (MSCs) were employed to build up a suitable environment within the scaffold for the culture of HSCs. Subsequently, primary human HSCs were seeded in this bone marrow mimicking environment. The whole culture was carried out within a microfluidic multi-organ-chip platform (2OC). Immunofluorescent staining, qPCR, and scanning electron microscopy data demonstrated that the MSCs had produced an appropriate environment for HSC cultivation. Using flow cytometry and CFU-GEMM assays, it could be shown that HSCs remained their native phenotype for at least eight weeks. Moreover, cells cultured for four weeks in the bone marrow model passed the gold standard test for native multipotent HSCs by successfully engrafting in irradiated immunocompromised mice. Here we present for the first time a novel human in vitro bone marrow model, capable of the successfully long-term culture of functional multipotent HSCs in a microfluidic environment.