A simple, cost-effective microfluidic device using a 3D cross-flow T-junction for producing decellularized extracellular matrix-derived microcarriers

Cell therapies using human mesenchymal stromal cells (MSCs) are promising for a wide variety of clinical applications. However, broad-scale clinical translation is limited by conventional culture methods for MSC expansion within 2D tissue-culture flasks. MSC expansion on ECM-derived microcarriers within stirred bioreactor systems offers a promising approach to support MSC growth. Previously, our team established methods for fabricating ECM-derived microcarriers from a variety of decellularized tissue sources using electrospraying techniques. However, these microcarriers are relatively large and have a broad size distribution, which may limit their utility. Smaller and more uniform microcarriers may be favorable for MSC growth within bioreactors and have greater potential to serve as a minimally invasive injectable cell delivery platform. To address these limitations, the current project focused on the development of a new microfluidic-based approach enabling both uniform and small microcarrier production. Using a novel, modified 3D T-junction design, we successfully generated microcarriers using human decellularized adipose tissue (DAT) as the ECM source. Our new cost-effective device produced microbeads that were small and monodisperse, at a range of flow rate combinations and with high production rates. Photo-crosslinking using rose bengal allowed for the generation of microcarriers that were stable following rehydration, with a mean diameter of 196 ± 47 µm. Following methods optimization and microcarrier characterization, in vitro studies confirmed that the new microcarriers supported human adipose-derived stromal cell (hASC) attachment and growth, as well as ECM production, across 14 days within spinner flask bioreactors. Overall, this study demonstrates the feasibility of using our novel, cost-effective, and reusable microfluidics device to generate cell-supportive microcarriers comprised exclusively of ECM in a size range that could be injected via a small gauge needle and were stable in long-term culture.