Microstructuring ceramic scaffolds for hepatocyte cell culture

Both extracorporeal liver support devices and tissue engineering of liver f or transplantation require the maintenance of functionality of liver cells (hepatocytes) in cell culture for a long time. One approach to achieve this is to optimize hepatocyte in vitro environment by using a scaffold with to pographic structure at sub-millimeter scale which controls cell distributio n. Therefore, a set of new type of titania ceramic scaffolds, containing ca vities of several sizes, has been produced for deducing the best choice of cavity dimensions for culturing hepatocytes. The aim of this paper is to de scribe in detail the production methods and characterization of such cerami c scaffolds. Experimental production of the scaffolds consists of microfabr ication of silicon templates as well as preparation and molding of titania ceramics. The templates, containing arrays of conical protrusions arranged in close-packed hexagonal order, have been achieved using microfabrication methods of photolithography and anisotropic etching in KOH at 50 degreesC. Protrusion dimensions and overall quality of the templates has been evaluat ed by scanning electron microscopy. The microfabricated templates have resu lted in well-defined and reproducible cavities of corresponding dimensions on the titania ceramic surface after injection-molding. Alternatively, simp le embossing of the plastified green ceramics with the silicon templates at tached to a metal plate also creates cavities on the ceramic surface. While both methods yield good results, they have different advantages: the injec tion-molding provides a higher quality of imprints while embossing is quick er and less complicated, and is not limited by dimensions of specific moldi ng equipment. (C) 2001 Kluwer Academic Publishers.