Preparation of agarose coated, solid agarose-collagen beads containing secretory cells

Abstract

Biological agents such as secretory cells are encapsulated in a hydrophilic gel made of agarose or collagen-agarose and gelatin sponge-agarose combinations. In a preferred embodiment, semi-solid beads are formed from a suspension containing collagen, agarose and secretory cells such as pancreatic islets, the collagen is polymerized to form solid, agarose-collagen beads and the solid beads are coated with agarose. Coating is preferably by rolling the solid beads in about 5-10% agarose, contacting the rolled beads with mineral oil and washing oil from the beads. Beads containing secretory cells can be transplanted into a mammal to treat a condition caused by impaired secretory cell function.

What is claimed is:  
     
       1. A method for preparing an agarose coated, solid agarose-collagen bead which contains secretory cells, comprising: 
       (a) suspending secretory cells in a collagen containing solution,  
       (b) adding agarose to said solution,  
       (c) forming a semi-solid bead of said collagen, agarose, and secretory cells,  
       (d) polymerizing collagen in said semisolid bead to form a solid, agarose-collagen bead containing secretory cells, and  
       (e) coating said solid, agarose-collagen bead containing secretory cells with agarose.  
     
     
       2. The method of  claim 1 , wherein said secretory cells are contained in pancreatic islets. 
     
     
       3. The method of  claim 2 , wherein said pancreatic islets are human pancreatic islets, bovine pancreatic islets, rat pancreatic islets or porcine pancreatic islets. 
     
     
       4. The method of  claim 3 , wherein said pancreatic islets are human pancreatic islets. 
     
     
       5. The method of  claim 1 , wherein said secretory cells are contained in from about 50,000 to about 700,000 pancreatic islets. 
     
     
       6. An agarose coated, solid agarose-collagen bead containing secretory cells prepared by the process of  claim 1 . 
     
     
       7. The agarose coated, solid agarose-collagen bead of  claim 6 , wherein said secretory cells are contained in pancreatic islets. 
     
     
       8. The agarose coated, solid agarose-collagen bead of  claim 6 , wherein said pancreatic islets are human pancreatic islets, bovine pancreatic islets, rat pancreatic islets or porcine pancreatic islets. 
     
     
       9. The agarose coated, solid agarose-collagen bead of  claim 8 , wherein said pancreatic islets are human pancreatic islets. 
     
     
       10. The agarose coated, solid agarose collagen bead of  claim 7 , comprising from about 50,000 to about 700,000 islets. 
     
     
       11. Method for treating a mammal having a condition caused by impaired secretory cell function, comprising: 
       transplanting into said mammal a therapeutically effective amount of the agarose coated, solid agarose-collagen bead of  claim 6 .  
     
     
       12. The method of  claim 11 , wherein said condition is insulin dependent diabetes. 
     
     
       13. The method of  claim 12 , wherein said bead contains cells derived from a pancreatic islet. 
     
     
       14. The method of  claim 13 , wherein said pancreatic islet is a human pancreatic islet. 
     
     
       15. The method of  claim 13 , wherein said pancreatic islet is a bovine pancreatic islet. 
     
     
       16. The method of  claim 13 , wherein said pancreatic islet is a porcine pancreatic islet. 
     
     
       17. The method of  claim 11 , wherein said bead is placed in the peritoneal cavity of said mammal. 
     
     
       18. The method of  claim 1 , comprising coating said bead with a solution containing from  5 %  to  10   %  agarose.   
     
     
       19. A composition of matter produced by combining a sample of secretory cells, gelatin sponge and a solution containing from  3 %  to  5   %  agarose to form a mixture, treating said mixture to form a bead and coating said bead with a coating which contains agarose.   
     
     
       20. The composition of matter of  claim 19 , wherein said secretory cells comprise pancreatic islet cells or pancreatic islets. 
     
     
       21. The composition of matter of  claim 20 , wherein said pancreatic islet cells or pancreatic islets are human, bovine, or porcine pancreatic islet cells or pancreatic islets. 
     
     
       22. The composition of matter of  claim 19 , wherein said solution comprises about  5 %  agarose.   
     
     
       23. The composition of matter of  claim 19 , wherein said coating comprises about  5 %  agarose.   
     
     
       24. The composition of matter of  claim 19 , comprising coating said bead with a solution containing from  5 %  to  10   %  agarose.   
     
     
       25. A method of producing a composition of matter comprising a sample of secretory cells contained in a bead which comprises agarose and collagen, wherein said bead is coated with a coating of agarose, comprising: 
       ( a )  suspending secretory cells in a solution containing collagen;    
       ( b )  adding agarose to said suspended secretory cells and collagen of step  ( a )  to form secretory cells suspended in a mixture of agarose and collagen,    
       ( c )  forming a collagen - agarose semisolid from said suspended secretory cells of step  ( b ),  
       ( d )  treating said collagen - agarose semisolid of step  ( c )  to polymerize collagen contained in said semisolid, to form a collagen - agarose bead having secretory cells entrapped therein,    
       ( e )  rolling the bead of step  ( d )  in  5   %  agarose, contacting said rolled bead to mineral oil, and washing said rolled bead.   
     
     
       26. The method of  claim 25 , wherein said secretory cells comprise pancreatic islet cells or pancreatic islets. 
     
     
       27. The method of  claim 26 , wherein said pancreatic islet cells or pancreatic islets are human, bovine or porcine pancreatic islet cells or pancreatic islets. 
     
     
       28. A method of producing a composition of matter comprising a sample of secretory cells entrapped in a bead, wherein said bead comprises agarose and gelatin sponge and is coated with a coating of agarose comprising: 
       ( a )  suspending secretory cells on gelatin sponge;    
       ( b )  adding agarose to said suspended secretory cells and gelatin sponge;    
       ( c )  forming a bead of the suspended secretory cells, gelatin sponge and agarose of  ( b );  and    
       ( d )  coating said bead with agarose.   
     
     
       29. The method of  claim 28 , wherein said secretory cells comprise pancreatic islets or pancreatic islet cells. 
     
     
       30. The method of  claim 29 , wherein said pancreatic islets or pancreatic islet cells are human, bovine, or porcine pancreatic islets or pancreatic islet cells. 
     
     
       31. The method of  claim 28 , comprising coating said bead with a solution containing from  5 %  to  10   %  agarose.   
     
     
       32. A method of producing a composition of matter comprising a sample of secretory cells entrapped in a bead, wherein said bead comprises gelatin sponge and from  3 %  to  5   %  agarose, and is coated with a coating of agarose, comprising:    
       ( a )  applying secretory cells to a gelatin sponge surface;    
       ( b )  adding a solution of from  3   %  to  5   %  agarose to said gelatin sponge surface;    
       ( c )  forming a bead; and    
       ( d )  coating said bead with agarose.   
     
     
       33. The method of  claim 32 , wherein said secretory cells comprise pancreatic islets or pancreatic islet cells. 
     
     
       34. The method of  claim 33 , wherein said pancreatic islets or pancreatic islet cells are human, bovine or porcine pancreatic islets or pancreatic islet cells. 
     
     
       35. The method of  claim 32 , comprising adding a  5 %  agarose solution to said gelatin sponge surface.   
     
     
       36. The method of  claim 32 , comprising coating said bead with a  5 %  agarose solution.   
     
     
       37. The method of  claim 32 , comprising coating said bead with a solution containing from  5 %  to  10   % agarose.