BIODEGRADABLE SPONGES FOR HEPATOCYTE TRANSPLANTATION

Liver cell transplantation may provide a means to replace lost or defi cient liver tissue, but devices capable of delivering hepatocytes to a desirable anatomic location and guiding the development of a new tiss ue from these cells and the host tissue are needed. We have investigat ed whether sponges fabricated from poly-L-lactic acid (PLA) infiltrate d with polyvinyl alcohol (PVA) would meet these requirements. Highly p orous sponges (porosity = 90-95%) were fabricated from PLA using a par ticulate leaching technique. To enable even and efficient cell seeding , the devices were infiltrated with the hydrophilic polymer polyvinyl alcohol (PVA). This reduced their contact angle with water from 79 to 23 degrees, but did not inhibit the ability of hepatocytes to adhere t o the polymer. Porous sponges of PLA infiltrated with PVA readily abso rbed aqueous solutions into 98% of their pore volume, and could be eve nly seeded with high densities (5 x 10(7) cells/mL) of hepatocytes. He patocyte-seeded devices were implanted into the mesentery of laborator y rats, and 6 +/- 2 x 10(5) of the hepatocytes engrafted per sponge. F ibrovascular tissue invaded through the devices' pores, leading to a c omposite tissue consisting of hepatocytes, blood vessels and fibrous t issue, and the polymer sponge. (C) 1995 John Wiley and Sons, Inc.