Collagen hydrogel tube microbioreactors for cell and tissue manufacturing.

The large-scale production of mammalian cells, particularly stem cells for clinical applications, remains challenging with existing cell culture technologies such as two-dimensional cell culture flasks or three-dimensional stirred tank bioreactors. Current methods have issues such as excessive cell aggregation and significant shear stress-induced cell death, resulting in low cell yield, unacceptable batch-to-batch variation, high production costs, and difficulties in scaling up. We hypothesize that creating a cell-friendly microenvironment that has efficient mass transport and minimized shear stress can enhance cell culture efficiency. In this study, we developed a novel hydrogel tube microbioreactor using collagen proteins (ColTubes) to test this hypothesis. First, we designed an innovative micro-extruder for fabricating ColTubes loaded with cells. Our results show that collagen proteins form a dense and robust nanofiber network capable of shielding cells from hydrodynamic stress while maintaining cell mass below 400µm in diameter. The tube shell contains abundant nanopores that allow the cell culture medium to permeate and nourish the cells. Additionally, the collagen fibers serve as a substrate for cell adhesion. We show that ColTubes support high cell viability, rapid expansion, and impressive volumetric yields, offering substantial improvements over current methods. To our knowledge, ColTubes is a novel approach that has not been previously reported for cell manufacturing. ColTubes represents a scalable, cost-effective, and efficient solution for large-scale cell production.