Injectable polysaccharide-cell compositions

Abstract

Slowly polymerizing polysaccharide hydrogels have been demonstrated to be 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.

We claim:  
     
         1 . A method for implanting tissue into an animal comprising 
 mixing a biodegradable, biocompatible hydrogel solution with dissociated cells and    implanting the mixture into the animal.    
     
     
         2 . The method of    claim 1    wherein the hydrogel solution is hardened prior to implantation in the animal.  
     
     
         3 . The method of    claim 1    wherein the hydrogel is injected into the animal as a cell suspension, which then hardens.  
     
     
         4 . The method of    claim 1    wherein the hydrogel is selected from the group consisting of alginate, polyphosphazines, polyethylene oxide-polypropylene glycol block copolymers, poly(acrylic acids), poly(methacrylic acids), copolymers of acrylic acid and methacrylic acid, poly(vinyl acetate), and sulfonated polymers.  
     
     
         5 . The method of    claim 4    wherein the hydrogel is hardened by exposure to an agent selected from the group consisting of ions, pH changes, and temperature changes.  
     
     
         6 . The method of    claim 5    wherein the hydrogel is hardened by interaction with ions selected from the group consisting of cations selected from the group consisting of copper, calcium, aluminum, magnesium, strontium, barium, tin, and di-, tri- or tetra-functional organic cations; anions selected from the group consisting of low molecular weight dicarboxylic acids, sulfate ions and carbonate ions.  
     
     
         7 . The method of    claim 4    wherein the hydrogel is further stabilized by cross-linking with a polyion.  
     
     
         8 . The method of    claim 1    wherein the cells are selected from the group consisting of chondrocytes and other cells that form cartilage, osteoblasts and other cells that form bone, muscle cells, fibroblasts, and organ cells.  
     
     
         9 . The method of    claim 1    wherein the hydrogel is molded to form a specific shape prior to implantation.  
     
     
         10 . The method of    claim 1    wherein the hydrogel is molded to form a specific shape after mixing with the cells and being implanted into the animal.  
     
     
         11 . A composition for implanting tissue into an animal comprising 
 a hydrogel solution mixed with dissociated cells.    
     
     
         12 . The composition of    claim 11    wherein the hydrogel solution is hardened prior to implantation in the animal.  
     
     
         13 . The composition of    claim 11    wherein the hydrogel is injected into the animal as a cell suspension, which then hardens.  
     
     
         14 . The composition of    claim 11    wherein the hydrogel is selected from the group consisting of alginate, polyphosphazines, polyethylene oxide-polypropylene glycol block copolymers, poly(acrylic acids), poly(methacrylic acids), copolymers of acrylic acid and methacrylic acid, poly(vinyl acetate), and sulfonated polymers.  
     
     
         15 . The composition of    claim 14    wherein the hydrogel is hardened by exposure to an agent selected from the group consisting of ions, pH changes, and temperature changes.  
     
     
         16 . The composition of    claim 15    wherein the hydrogel is hardened by interaction with ions selected from the group consisting of cations selected from the group consisting of copper, calcium, aluminum, magnesium, strontium, barium, tin, and di-, tri- or tetra-functional organic cations; anions selected from the group consisting of low molecular weight dicarboxylic acids, sulfate ions and carbonate ions.  
     
     
         17 . The composition of    claim 14    wherein the hydrogel is further stabilized by cross-linking with a polyion.  
     
     
         18 . The composition of    claim 11    wherein the cells are selected from the group consisting of chondrocytes and other cells that form cartilage, osteoblasts and other cells that form bone, muscle cells, fibroblasts, and organ cells.