Fabrication of tubular tissue constructs by centrifugal casting of cells suspended in an in situ crosslinkable hyaluronan-gelatin hydrogel.

Achieving the optimal cell density and desired cell distribution in scaffolds is a major goal of cell seeding technologies in tissue engineering. In order to reach this goal, a novel centrifugal casting technology was developed using in situ crosslinkable hyaluronan-based (HA) synthetic extracellular matrix (sECM). Living cells were suspended in a viscous solution of thiol-modified HA and thiol-modified gelatin, a polyethyleneglycol diacrylate crosslinker was added, and a hydrogel was formed during rotation. The tubular tissue constructs consisting of a densely packed cell layer were fabricated with the rotation device operating at 2000 rpm for 10 min. The majority of cells suspended in the HA mixture before rotation were located inside the layer after centrifugal casting. Cells survived the effect of the centrifugal forces experienced under the rotational regime employed. The volume cell density (65.6%) approached the maximal possible volume density based on theoretical sphere packing models. Thus, centrifugal casting allows the fabrication of tubular constructs with the desired redistribution, composition and thickness of cell layers that makes the maximum efficient use of available cells. Centrifugal casting in this sECM would enable rapid fabrication of tissue-engineered vascular grafts, as well as other tubular and planar tissue-engineered constructs.