Fabrication of a 3D microfluidic cell culture device for bone marrow-on-a-chip

Abstract Conventional biomedical research models are confined to static cell culture models and animal testing, both of them representing suboptimal preclinical models. Organs-on-chips (OOCs) are novel 3D microfluidic cell culture devices lined with living cells that allow for faithful mimicry of the physiology and function of a vital human organ unit. Bone marrow-on-a-chip (BMoC) systems are currently limited to in vitro maintenance of the hematopoietic potential, supported with 3D scaffold matrices. Herein, we introduce a purely in vitro and scaffold-free bone marrow-on-a-chip device, intended for both the generation and sustainment of the perivascular hematopoietic niche, to serve as a study platform for the chronic autoimmune disease of systemic lupus erythematosus (SLE). The device consists of three layers of poly(dimethylsiloxane) (PDMS), including two cylindrical microchambers separated by an intervening porous membrane, altogether bonded to a glass slide. In this communication, the fabrication steps for a reliable and reproducible BMoC device are presented, from its design to its final assembly. As a first step towards the full recapitulation of the perivascular niche on-chip, the bone marrow stromal niche was replicated inside sealed type I collagen-coated microchambers hosting the in vitro 3D microfluidic culture of mesenchymal stem cells (MSCs) for 8 days. Culture of the MSCs revealed significant cell proliferation and progressive formation of 3D stromal tissue, a promising outcome for the subsequent 3D stromal matrix growth on the bone marrow-on-a-chip platform.