Title:  Injectable hydrogel compositions

United States Patent:  6,129,761

Assignee:  Reprogenesis, Inc. (Charlotte, NC)

Filed:  June 7, 1995

Slowly polymerizing hydrogels are provided which are useful as a means of delivering large numbers of isolated cells via injection. The gels promote engraftment and provide three dimensional templates for new cell growth. The resulting tissue is similar in composition and histology to naturally occurring tissue. This method can be used for a variety of reconstructive procedures, including custom molding of cell implants to reconstruct three dimensional tissue defects, as well as implantation of tissues generally. The polymers permit construction of muscle and cartilage tissues which are useful to repair defects such as reflux and incontinence.

SUMMARY OF THE INVENTION

Slowly polymerizing, biocompatible, biodegradable hydrogels are provided which are useful for delivering large numbers of isolated cells into a patient to create an organ equivalent or tissue such as cartilage. The gels promote engraftment and provide three dimensional templates for new cell growth. The resulting tissue is similar in composition and histology to naturally occurring tissue. In one embodiment, cells are suspended in a polymer solution and injected directly into a site in a patient, where the polymer crosslinks to form a hydrogel matrix having cells dispersed therein. In a second embodiment, cells are suspended in a polymer solution which is poured or injected into a mold having a desired anatomical shape, then crosslinked to form a hydrogel matrix having cells dispersed therein which can be be implanted into a patient. Ultimately, the hydrogel degrades, leaving only the resulting tissue.

This method can be used for a variety of reconstructive procedures, including custom molding of cell implants to reconstruct three dimensional tissue defects, as well as implantation of tissues generally.

In another embodiment, a method of treatment of vesicoureteral reflux, incontinence and other defects is provided wherein bladder muscle cells are mixed with a liquid polymeric material, to form a cell suspension, which is injected into the area of the defect, in an amount effective to yield a tissue that corrects the defect, for example, which provides the required control over the passage of urine. In one embodiment, human bladder muscle specimens or chondrocytes are obtained and processed, the cells are mixed with the polymer, which is designed to solidify at a controlled rate when contacted with a crosslinking agent, and then the cells are injected at the desired site where they proliferate and correct the defect.

Claim 1 of 17 Claims

We claim:

1. A method for making and implanting a cell-hydrogel suspension into an animal comprising

mixing dissociated cells with a solution comprising a biocompatible polymer capable of crosslinking to form a hydrogel to form a cell-polymer suspension, wherein the polymer is selected from the group consisting of (a) modified hyaluronic acids, (b) synthetic modified alginates, (c) polymers which are covalently crosslinkable by a radical reaction and (d) polymers which gel by exposure to monovalent ions;

implanting the suspension into the animal; and

permitting the biocompatible polymer to crosslink and form a hydrogel matrix having the dissociated cells dispersed therein.

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