Semi-interpenetrating or interpenetrating polymer networks for drug delivery and tissue engineering
First Claim
1. A method for forming a tissue equivalent in a patient, comprising:
- providing a suspension of dissociated cells in a solution of a biocompatible polymer, wherein the polymer crosslinks upon exposure to free radicals to form a hydrogel, injecting said suspension into a patient, and exposing the suspension in situ to free radicals generated by electromagnetic radiation from an electromagnetic source external to the injected suspension, the electromagnetic radiation penetrates through tissue to generate the free radicals which cause polymer crosslinking and whereby the tissue equivalent forms.
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Accused Products
Abstract
Compositions for tissue engineering and drug delivery have been developed based on solutions of two or more polymers which form semi-interpenetrating or interpenetrating polymer networks upon exposure to active species following injection at a site in a patient in need thereof. The polymers crosslink to themselves but not to each other; semi-interpenetrating networks are formed when only one of the polymers crosslink. The resulting viscous solutions retain the biologically active molecules or cells at the site of injection until release or tissue formation, respectfully, occurs.
As a result of studies conducted with polymer-cell suspensions forming interpenetrating polymer networks, it has been determined that polymer solutions can be formulated wherein the active species is provided by exposure of the polymer solution to an exogenous souce of active species, typically electromagnetic radiation, preferably light. Studies demonstrate that light will penetrate through skin, body fluids (such as synovial fluid) and membranes and polymerize the polymer solutions. The polymer solutions can be crosslinked ionically or covalently, to form a hydrogel, semi-interpenetrating polymer network or an interpenetrating polymer network.
290 Citations
26 Claims
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1. A method for forming a tissue equivalent in a patient, comprising:
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providing a suspension of dissociated cells in a solution of a biocompatible polymer, wherein the polymer crosslinks upon exposure to free radicals to form a hydrogel, injecting said suspension into a patient, and exposing the suspension in situ to free radicals generated by electromagnetic radiation from an electromagnetic source external to the injected suspension, the electromagnetic radiation penetrates through tissue to generate the free radicals which cause polymer crosslinking and whereby the tissue equivalent forms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A composition for implanting cells or biologically active molecules in a mammal comprising:
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(a) disassociated cells and/or biologically active molecules;
(b) an injectable polymer solution comprising (i) a first polymer which is covalently-crosslinkable;
(ii) a second polymer which is covalently-crosslinkable; and
(c) a photoinitiator;
wherein said photoinitiator initiates polymerization upon exposure to electromagnetic radiation so that (i) and (ii) crosslink to themselves and not to each other forming an interpenetrating network. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26)
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11. A composition for implanting cells or biologically active molecules in a mammal comprising:
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(a) disassociated cells and/or biologically active molecules;
(b) an injectable polymer solution comprising (i) a polymer which upon polymerization covalently crosslinks forming a porous network; and
(ii) a second polymer which upon polymerization does not crosslink and becomes trapped within the porous network of the first polymer; and
(c) a photoinitiator;
wherein said photoinitiator initiates polymerization upon exposure to electromagnetic radiation so that (i) and (ii) form a semi-interpenetrating network. - View Dependent Claims (20)
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Specification