Encapsulation of biological material
First Claim
1. A process for encapsulating viable tissue within a semipermeable membrane, said process comprising the steps of:
- A. suspending finely divided living tissue in an aqueous medium which is physiologically compatible with the tissue and which contains a water soluble substance which(a) is physiologically compatible with the tissue;
and(b) can be reversibly gelled to form a coherent, shape-retaining mass;
B. forming the suspension into droplets of a size sufficient to envelop tissue;
C. gelling the droplets to form discrete, shape-retaining temporary capsules;
D. forming a permanent semipermeable membrane about the temporary capsules; and
E. reliquifying the gel within the membrane.
2 Assignments
0 Petitions
Accused Products
Abstract
A core material such as living tissue, individual cells, hormones, enzymes or antibodies is encapsulated in a semipermeable membrane that is permeable to small molecules for contact with the core material but is impermeable to potentially deleterious large molecules. Encapsulation may be carried out by suspending the core material in an aqueous medium containing a water soluble gum that can be reversibly gelled, forming the suspension into droplets, contacting the droplets with a solution of multivalent cations to gel the droplets as discrete, shape-retaining, water insoluble temporary capsules and cross-linking a surface layer of the temporary capsules to produce a semipermeable membrane around the capsules. Optionally the gel within the membrane may be reliquified by removing multivalent cations from the gel.
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Citations
22 Claims
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1. A process for encapsulating viable tissue within a semipermeable membrane, said process comprising the steps of:
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A. suspending finely divided living tissue in an aqueous medium which is physiologically compatible with the tissue and which contains a water soluble substance which (a) is physiologically compatible with the tissue; and (b) can be reversibly gelled to form a coherent, shape-retaining mass; B. forming the suspension into droplets of a size sufficient to envelop tissue; C. gelling the droplets to form discrete, shape-retaining temporary capsules; D. forming a permanent semipermeable membrane about the temporary capsules; and E. reliquifying the gel within the membrane.
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2. A process for encapsulating a core material within a semipermeable membrane, said process comprising the steps of:
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A. placing the material in a solution of a water-soluble substance that can be reversibly gelled; B. forming the solution into droplets; C. gelling the droplets to produce discrete shape-retaining temporary capsules; D. forming semipermeable membranes about the temporary capsules; and E. reliquifying the gel within said membranes. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A process for encapsulating a core material within a membrane permeable to proteins of a molecular weight no greater than about 100 thousand daltons, said process comprising the steps of:
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A. suspending the core material in an aqueous medium which contains a water-soluble gum containing acid groups; B. forming the suspension into droplets; C. subjecting the droplets to a solution of multivalent, cations to gel the droplets as discrete, shape-retaining, water insoluble temporary capsules; and D. permanently cross-linking surface layers of said temporary capsules to produce a semipermeable membrane about said droplets by subjecting them to a polymer containing substitutents reactive with the acid groups of said gum, said polymer having a molecular weight within the range of 3000-100,000 daltons. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification