Optimizing cell seeding and retention in a three-dimensional bioengineered cardiac ventricle: The two-stage cellularization model.

Current cell seeding techniques focus on passively directing cells to a scaffold surface with the addition of dynamic culture to encourage cell permeation. In 3D tissue engineered constructs, cell retention efficiency is dependent on the cell delivery method, and biomaterial properties. Passive cell delivery relies on cell migration to the scaffold surface; biomaterial surface properties and porosity determine cell infiltration capacity. As a result, cell retention efficiencies remain low. The development of an effective two-stage cell seeding technique, coupled with perfusion culture, provides the potential to improve cellularization efficiency, and retention. This study, uses a chitosan bioengineered open ventricle (BEOV) scaffold to produce a two-stage perfusion cultured ventricle (TPCV). TPCV were fabricated by direct injection of 10 million primary rat neonatal cardiac cells, followed by wrapping of the outer scaffold surface with a 3D fibrin gel artificial heart muscle patch; TPCV were perfusion cultured for 3 days. The average biopotential output was 1.731 mV. TPCV cell retention following culture was approximately 5%. Cardiac cells were deposited on the scaffold surface and formed intercellular connections. Histological assessment displayed localized cell clusters, with some dissemination, and validated the observed presence of intercellular and gap-junction interactions. The study demonstrates initial effectiveness of our two-stage cell delivery concept, based on function and biological metrics. Biotechnol. Bioeng. 2016;113: 2275-2285. © 2016 Wiley Periodicals, Inc.