Novel design of a chitosan-collagen scaffold for hepatocyte implantation

Implantation of a bioartificial liver, composed of a hepatocyte seeded scaffold, has the potential to offer new treatment options for liver diseases. One of the problems associated with hepatocyte transplantation is the need to ensure adequate oxygenation in the short term and angiogenesis in the long term. The primary goal of this project is to develop a chitosan based scaffold capable of overcoming these problems. In this study we describe the design of a cylindrical shaped chitosan-collagen scaffold with radial pores originating at a central port. To generate this microstructure a chitosan-collagen solution was frozen under controlled rate and radial thermal gradient conditions and then lyophilized. Microstructure was examined using SEM. Rehydrated scaffolds were equilibrated with culture medium and seeded with either aggregated or single cell hepatocytes through a central injection port. MTT staining, fluorescence microscopy, and SEM were used to examine cell distribution, attachment, viability and morphology. SEM imaging showed that scaffolds had long tapering pores with diameters ranging from 50 /spl mu/m at the port to 10 /spl mu/m at the external surface. This microstructure allowed for efficient cell seeding via the central port. Single cells and aggregated hepatocytes were evenly distributed throughout the scaffold and attached to pore walls. Also discussed is the next phase of scaffold design, which addresses the need for immediate oxygenation by seeded cells.