Formation of 3D tissues of primary hepatocytes using fibrillized collagen microparticles as intercellular binders

Numerous attempts have been made to organize isolated primary hepatocytes into functional three-dimensional (3D) constructs, but technologies to introduce extracellular matrix (ECM) components into such assemblies have not been fully developed. Here we report a new approach to forming hepatocyte-based 3D tissues using fibrillized collagen microparticles (F-CMPs) as intercellular binders. We created thick tissues with a thickness of ∼200 μm simply by mixing F-CMPs with isolated primary rat hepatocytes and culturing them in cell culture inserts. Owing to the incorporated F-CMPs, the circular morphology of the formed tissues was stabilized, which was strong enough to be manually manipulated and retrieved from the chamber of the insert. We confirmed that the F-CMPs dramatically improved the cell viability and hepatocyte-specific functions such as albumin production and urea synthesis in the formed tissues. The presented approach provides a versatile strategy for hepatocyte-based tissue engineering, and will have a significant impact on biomedical applications and pharmaceutical research.