title: Radial flow hepatocyte bioreactor using stacked microfabricated grooved substrates.
abstract: Bioartificial liver (BAL) devices with fully functioning hepatocytes have the potential to provide temporary hepatic support for patients with liver failure. The goal of this study was to optimize the flow environment for the cultured hepatocytes in a stacked substrate, radial flow bioreactor. Photolithographic techniques were used to microfabricate concentric grooves onto the underlying glass substrates. The microgrooves served to protect the seeded hepatocytes from the high shear stresses caused by the volumetric flow rates necessary for adequate convective oxygen delivery. Finite element analysis was used to analyze the shear stresses and oxygen concentrations in the bioreactor. By employing high volumetric flow rates, sufficient oxygen supply to the hepatocytes was possible without an integrated oxygen permeable membrane. To implement this concept, 18 microgrooved glass substrates, seeded with rat hepatocytes cocultured with 3T3-J2 fibroblasts, were stacked in the bioreactor, creating a channel height of 100 microm between each substrate. In this bioreactor configuration, liver-specific functions (i.e., albumin and urea synthesis rates) of the hepatocytes remained stable over 5 days of perfusion, and were significantly increased compared to those in the radial flow bioreactor with stacked substrates without microgrooves. This study suggests that this radial flow bioreactor with stacked microgrooved substrates is scalable and may have potential as a BAL device in the treatment of liver failure.
authors.affiliation: Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Shriners Hospitals for Children and Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Jaesung
authors.initials: J
authors.lastname: Park
authors.forename: Yawen
authors.initials: Y
authors.lastname: Li
authors.forename: François
authors.initials: F
authors.lastname: Berthiaume
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toner
authors.forename: Martin L
authors.initials: ML
authors.lastname: Yarmush
authors.forename: Arno W
authors.initials: AW
authors.lastname: Tilles
mesh_terms: D000818:Animals; D019149:Bioreactors; D018920:Coculture Techniques; D004867:Equipment Design / Q000295:instrumentation*; D005260:Female; D005347:Fibroblasts; D022781:Hepatocytes / Q000378:metabolism*; D019164:Liver, Artificial; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D051381:Rats