Biocompatible microcapsules

DETAILED DESCRIPTION This invention for the first time demonstrates the use of water soluble non-ionic polymers such as PEO to create resistance to cell adhesion on the surface of microcapsules.
This invention provides a method for transplanting foreign material into an animal body in a biocompatible manner.
This is accomplished by providing microcapsules, biocompatible with the recipient animal, capable of encapsulating the foreign material to be transplanted into that animal.
The normally charged outer layer of the microcapsules is covered by water soluble non-ionic polymers such as poly(ethylene oxide) (PEO) which act to shield the charge.
These polymers are grafted to the polycationic polymers, such as poly-L-lysine (PLL) molecules used as at least one of the layers of the microcapsule, such that they create a non-ionic barrier between the outer layer of the microcapsule (made of essentially either polycationic polymers, such as PLL, or polyanionic polymers, such as alginate) and the recipient animal.
The microcapsules then appear, from the outside, to have water-like surface properties, thus reducing the driving force for protein adsorption.
Further, the surface, at the macromolecular level, is in a high degree of motion, further reducing protein adsorption and cell attachment.
This invention further provides microcapsules, and a method for their production, in which the surface is more resistant to cell adhesion.
As a result, overgrowth of the microcapsules by cells such as fibroblasts and macrophages is severely decreased or eliminated.
Cells contained within the microcapsules are able to continue to receive nutrients and signal molecules, and produce whatever is their desired product.
Any product present in the microcapsules, such as insulin produced by islet cells, can continue to diffuse out of the microcapsules and be available for utilization by the host animal.
This invention also provides microcapsules, and a method for their production, which will not appreciably stimulate immune response or cytokine release by the recipient animal