Malleable, cryopreserved osteogenic compositions with viable cells

Abstract

A bone graft composition comprising a viable, osteogenic cellular material combined with a viscous cryoprotectant that includes a penetrating cryoprotective agent and a non-penetrating cryoprotective agent. The viscosity of the cryoprotectant is such that the composition is malleable, cohesive and capable of being formed into desired shapes.

We claim: 
     
         1 . A bone graft composition comprising:
 bone particles containing viable osteogenic cellular material native to the bone particles;   a viscous cryoprotectant comprising at least one penetrating cryoprotective agent and at least one non-penetrating cryoprotective agent, wherein the at least one non-penetrating cryoprotective agent comprises alginate,   wherein the viscous cryoprotectant comprises a concentration of alginate of at least 4%; and   a demineralized bone matrix,   wherein the bone graft composition is homogenous and malleable.   
     
     
         2 . The bone graft composition of  claim 1 , wherein a first volume ratio of the bone particles to the demineralized bone matrix is in a range from 5:2 to 5:3. 
     
     
         3 . The bone graft composition of  claim 2 , wherein a second volume ratio of the bone particles to the viscous cryoprotectant is from 5:2 to 2:1. 
     
     
         4 . The bone graft composition of  claim 1 , wherein the bone particles are from viable cancellous bone, and the demineralized bone matrix is from cortical bone. 
     
     
         5 . The bone graft composition of  claim 1 , wherein at least seventy-four percent of the viable osteogenic cellular material is viable after storage in the cryopreservative at −80 degrees Celsius or lower for a period of fourteen days. 
     
     
         6 . The bone graft composition of  claim 1 , wherein the bone particles are cohesively bound by the viscous cryoprotectant. 
     
     
         7 . The bone graft composition of  claim 1 , wherein the bone particles are coated or encapsulated by the viscous cryoprotectant. 
     
     
         8 . The bone graft composition of  claim 1 , wherein a viscosity of the viscous cryoprotectant is higher than 2000 centipoises (cps). 
     
     
         9 . The bone graft composition of  claim 1 , wherein the at least one non-penetrating cryoprotective agent further comprises one or more of hyaluronic acid, hydroxyethyl starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, polyvinylpyrrolidone, polyethylene glycol, chitosan, and glycerol, and wherein the at least one penetrating cryoprotective agent is one of dimethyl sulfoxide, glycerol, propylene glycol, ethylene glycol, propanediol, or a combination thereof. 
     
     
         10 . The bone graft composition of  claim 1 , wherein the viscous cryoprotectant comprises a concentration of alginate of at least 6%, and wherein at least eighty-five percent of the viable osteogenic cellular material is viable after storage in the cryopreservative at −80 degrees Celsius or lower for a period of fourteen days. 
     
     
         11 . A method of preserving viability of a bone graft composition, the method comprising:
 combining a viable bone graft material with a demineralized bone matrix, wherein the viable bone graft material contains viable osteogenic cells inherent thereto; and   combining the viable bone graft material and the demineralized bone matrix with a viscous cryoprotectant into a homogenous composition for preserving the viability of the viable bone graft material, wherein the viscous cryoprotectant includes at least one non-penetrating cryoprotective agent and at least one penetrating cryoprotective agent, wherein the at least one non-penetrating cryoprotective agent comprises alginate, and wherein the viscous cryoprotectant comprises a concentration of alginate of at least 4%.   
     
     
         12 . The method claim of  11 , wherein a first volume ratio of the viable bone graft to the demineralized bone matrix ranges from 5:2 to 5:3, and a second volume ratio of the viable bone graft material to the viscous cryoprotectant is from 5:2 to 2:1. 
     
     
         13 . The method claim of  11 , wherein:
 a) the viable bone graft material is from viable cancellous bone, and the demineralized bone matrix is from viable cortical bone,   b) the viable bone graft material is from viable cortical bone, and the demineralized bone matrix is from viable cancellous bone, or   c) the viable bone graft material is cohesively bounded by the viscous cryoprotectant.   
     
     
         14 . The method claim of  11 , wherein at least seventy-four percent of the viable osteogenic cells are viable after storage in the cryopreservative at −80 degrees Celsius or lower for a period of fourteen days. 
     
     
         15 . The method claim of  11 , wherein the viable bone graft material is coated or encapsulated by the viscous cryoprotectant, wherein the viscous cryoprotectant comprises a concentration of alginate of at least 6%, and wherein at least eighty-five percent of the viable osteogenic cellular material is viable after storage in the cryopreservative at −80 degrees Celsius or lower for a period of fourteen days. 
     
     
         16 . The method claim of  11 , wherein a viscosity of the viscous cryoprotectant is higher than 2000 centipoises (cps). 
     
     
         17 . The method claim of  11 , wherein the at least one non-penetrating cryoprotective agent further comprises one or more of hyaluronic acid, hydroxyethyl starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, polyvinylpyrrolidone, polyethylene glycol, chitosan, and glycerol. 
     
     
         18 . The method claim of  11 , wherein the at least one penetrating cryoprotective agent is one of dimethyl sulfoxide, glycerol, propylene glycol, ethylene glycol, propanediol, or a combination thereof. 
     
     
         19 . A bone graft composition comprising:
 bone particles containing viable osteogenic cellular material native to the bone particles;   a viscous cryoprotectant comprising at least one penetrating cryoprotective agent and at least one non-penetrating cryoprotective agent, wherein the at least one non-penetrating cryoprotective agent comprises alginate; and   a demineralized bone matrix,   wherein the bone graft composition is homogenous and malleable,   wherein at least seventy-four percent of the viable osteogenic cellular material is viable after storage in the cryopreservative at −80 degrees Celsius or lower for a period of fourteen days.   
     
     
         20 . The bone graft composition of  claim 19 , wherein at least eighty percent of the viable osteogenic cellular material is viable after storage in the cryopreservative at −80 degrees Celsius or lower for the period of fourteen days.