United States Patent:   6,020,200

Assignee:  Metabolex, Inc. (Hayward, CA)

Filed:  March 1, 1996

The present invention generally relates to novel encapsulation compositions and methods. In particular, the invention relates to stabilized microcapsule compositions which comprise a layer of a crosslinked, mixed functionality, polymer matrix, and methods for their preparation. The encapsulated compositions may comprise the crosslinked polymer matrix layer as an inner layer, an outer layer, or an intermediate layer of an overall encapsulated composition. The compositions will generally also comprise a biological material, e.g., cells, proteins, and the like, encapsulated within the composition. The compositions and methods of the invention are useful in a variety of applications, including cell culturing and transplant therapy.

SUMMARY OF THE INVENTION

One aspect of the present invention provides stabilized microcapsule compositions which comprise at least one layer of a stabilized, crosslinked, mixed functionality polymer matrix having a defined matrix porosity (hereinafter referred to as "crosslinked polymer matrix"). In preferred aspects, the microcapsule compositions of the present invention comprise biological material coated with the layer of crosslinked polymer matrix. The biological material may be free, encapsulated or bound to a support. Preferred polymer matrices include those comprising coliagen and derivatized alginate. The compositions may optionally comprise an additional layer of a biocompatible polymer, coating the crosslinked polymer matrix layer.

Also provided by the present invention are methods of encapsulating biological material. The methods comprise placing the biological material into a solution of a mixed functionality polymer which is capable of being crosslinked, whereby the polymer nucleates around said biological material. The polymer matrix is then crosslinked to produce a stabilized layer of crosslinked polymer matrix with a controllable porosity. Again, the biological material can be free, encapsulated or support bound prior to coating with crosslinked polymer matrix. Preferably, the biological material is encapsulated in a first composition prior to coating with the crosslinked polymer matrix.

In a further embodiment, the present invention provides methods of treating disorders that are characterized by the absence of a particular biological function in a patient. The methods comprise introducing into a patient, an encapsulated composition of biological material capable of performing the particular absent biological function, the material being encapsulated according to the methods of the present invention. In preferred aspects, the encapsulated biological material is pancreatic islet cells and the method is used to treat diabetes mellitus.

In another embodiment, the present invention provides a method of culturing cells. The method comprises coating-the cells with a layer of crosslinked, mixed functionality, polymer matrix according to the methods of the invention, and culturing the cells.

Claim 1 of 3 Claims

1. A method of culturing viable cells, comprising coating said cells with at least one self-assembled layer of crosslinked mixed functionality polymer, and culturing said cells.

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