Artificial cells as bioreactive biomaterials

Artificial cells can have the same dimensions as biological cells. They can enclose and retain a large variety of bioreactants. Artificial cell membranes can have the required permeability characteristics to allow the rapid equilibration of external molecules to be acted on by the enclosed bioreactants. Polymer, protein, protein-lipid, polymer-lipid, lipid or other materials can form artificial cell membranes. It is possible to vary the membrane thickness and permeability characteristics over a wide range. Many different forms of bioreactive artificial cells are available. This article contains only a few examples. This includes its applications in (1) red blood cell substitutes; (2) immobilisation of enzymes, multienzymes with cofactor recycling, cell cultures and other biotechnological applications; (3) hemoperfusion in kidney failure, poisoning, removal of aluminum and iron; (4) use in liver failure; (5) other applications in microencapsulation.

The viability and regeneration of artificial cell microencapsulated rat hepatocyte xenograft transplants in mice

Viable hepatocytes were microencapsulated within artificial cells to form a bio-artificial liver. Trypan blue stain exclusion testing generally showed that 60% of the encapsulated hepatocytes remained viable immediately after encapsulation. To determine if xenogeneic hepatocytes can be successfully transplanted, encapsulated rat hepatocytes were implanted intra-peritoneally into mice and galactosamine induced liver failure mice. After 29 days of implantation in mice and 8 days of implantation in liver failure induced mice there was no significant change observed in the number of hepatocytes within the free floating microcapsules recovered from the peritoneal cavity. The percentage viability of the hepatocytes inside the recovered microcapsules increased from 62% to nearly 100% after 29 days of implantation in mice. The percentage viability of the encapsulated hepatocytes implanted in the liver failure induced mice was followed for 8 days. The percentage viability of the hepatocytes inside the microcapsule also increased from 42% to nearly 100%. In mice implanted with free rat hepatocytes, no viable hepatocytes were observed as early as 4 and 5 days after implantation. Instead a larger number of lymphoid cells and remnants of hepatocytes were recovered from the peritoneal cavity. In all cases the viability of the rat hepatocytes were determined with trypan blue stain.

Applications of artificial cells in medicine and biotechnology

This article summarizes those research activities in the area of artificial cells which are related to medicine and biotechnology. This includes the applications of artificial cells in: (1) chronic renal failure, (2) drug poisoning, (3) aluminium and iron removal, (4) fulminant hepatic failure, (5) immunosorbent for direct blood perfusion, (6) enzyme therapy and metabolic function replacement, (7) immobilized cell cultures for Bioartificial Organs, (8) blood substitutes, (9) microencapsulation, (10) biotechnology and other areas.