Expression of Liver-Specific Functions by Rat Hepatocytes Seeded in Treated Poly(Lactic- co -Glycolic) Acid Biodegradable Foams

Abstract

Techniques of liver replacement would benefit patients awaiting donor livers and may be a substitute for transplantation in patients whose livers can regenerate. Poly(lactic-co-glycolic acid) (PLGA) copolymers are biodegradable and have been shown to be useful as scaffolds for seeding and culturing various types of cells. In this study, foam disks were prepared from PLGA (lactic-to-glycolic mole ratio of 85:15) by lyophilization of benzene (5% w/v) solutions. These disks were then used as scaffolds for rat hepatocyte culture. Foams were coated with either a type I collagen gel (0.1% w/v), coated with gelatin (5% w/v), or treated with oxygen plasma (25 W, 90 s) to modify their surface chemistry and wettability. The disks were then seeded with rat hepatocytes (10⁶/mL) and cultured for a period of 2 weeks. All surface treatments resulted in increased hydrophilicity, the greatest being obtained by collagen treatment (contact angle < 10°), and a minimal decrease in void fraction (5%). DNA content after a 2-week culture period increased proportionally with the wettability of the treated foam surface. Urea synthesis in untreated foams averaged 15.3 ± 2.3 μg/h/μg DNA, which was significantly higher than that for controls, whereas gelatin and collagen treated foams exhibited urea synthetic rates below the control levels at all times. The DNA content decreased significantly by about 50% between days 1 and 12. PLGA foams, treated and untreated, represent a promising scaffold for scaling up hepatocyte cultures.