a method is disclosed whereby cells having a desired function are seeded on and into biocompatible , biodegradable or non - degradable polymer scaffolding , previously implanted in a patient and infiltrated with blood vessels and connective tissue , to produce a functional organ equivalent . the resulting organoid is a chimera formed of parenchymal elements of the donated tissue and vascular and matrix elements of the host . the matrix should be a non - toxic , injectable porous template for vascular ingrowth . the pore size , usually between approximately 100 and 300 microns , should allow vascular and connective tissue ingrowth throughout approximately 10 to 90 % of the matrix , and the injection of cells such as hepatocytes without damage to the cells or patient . the introduced cells attach to the connective tissue and are fed by the blood vessels . immediately prior to polymer implantation portacaval shunts can be created to provide trophic stimulatory factors to the implants to enhance replication and function .