A method for making a porous scaffold suitable for use in repair of osseous, chondral, or osteochondral defects in a mammal

Abstract

A method for making a porous devitalised scaffold suitable for use in repair of osseous, chondral, or osteochondral defects in a mammal comprises the steps of providing micronized extracellular matrix (ECM) tissue, mixing the micronized extracellular matrix with a liquid to provide a slurry, and freeze-drying the slurry to provide the porous scaffold. A porous scaffold suitable for use in repair of osseous, chondral, or osteochondral defects in a mammal and comprising a porous freeze-dried matrix formed from micronised decellularised extracellular matrix tissue is also described.

1 .- 65 . (canceled) 
     
     
         66 . A method for making a porous scaffold suitable for use in repair of osseous, chondral, or osteochondral defects in a mammal, the method comprising the step of:
 providing micronized extracellular matrix (ECM) tissue;   mixing the micronized extracellular matrix with a liquid to provide a slurry; and   freeze-drying the slurry to provide the porous scaffold,   
       wherein the extracellular matrix is treated to reduce the GAG content to less than 90% of the GAG content of untreated ECM, and wherein the ECM tissue is cartilage ECM. 
     
     
         67 . A method according to  claim 66  in which the micronized cartilage extracellular matrix tissue has a mean particle size of 10-200 microns. 
     
     
         68 . A method according to  claim 66  in which the slurry comprises 100-400 mg/ml micronized cartilage ECM tissue. 
     
     
         69 . A method according to  claim 66  in which the micronized cartilage extracellular matrix tissue is cryomilled cartilage extracellular matrix tissue. 
     
     
         70 . A method according to  claim 66  in which the porous scaffold is cross-linked. 
     
     
         71 . A method according to  claim 66  in which the cartilage extracellular matrix is hyaline cartilage ECM or growth plate ECM. 
     
     
         72 . A method according to  claim 66  in which the cartilage extracellular matrix is decellularised before or after micronizing. 
     
     
         73 . A method according to  claim 66  in which the method of the invention includes an additional step of seeding the scaffold with a biological material selected from cells or a biological growth factor. 
     
     
         74 . A method according to  claim 73  in which: the cells are selected from the group consisting of stem cells, chondrocytes, mesenchymal cells and osteoblasts; and/or in which the biological growth factor is selected from the group consisting of one or more of the TGF-β superfamily or cannabinoids. 
     
     
         75 . A method of making a multilayer scaffold comprising the steps of making a first layer comprising a porous scaffold according to a method of  claim 66 , making a second layer comprising a porous scaffold according to a method of  claim 66 , wherein the first layer is attached to the second layer. 
     
     
         76 . A method according to  claim 75  in which the process includes a step of attaching the first layer to the second layer to form the multilayer scaffold, in which the first layer comprises hyaline cartilage ECM and the second layer comprises growth plate ECM. 
     
     
         77 . A porous scaffold suitable for use in repair of osseous, chondral, or osteochondral defects in a mammal and comprising a porous freeze-dried matrix formed from micronised decellularised extracellular matrix tissue, wherein the extracellular matrix tissue comprises less than 90% of the GAG content of natural ECM, and wherein the extracellular matrix tissue is cartilage extracellular matrix tissue. 
     
     
         78 . A porous scaffold according to  claim 77  in which the porous scaffold is cross-linked. 
     
     
         79 . A porous scaffold according to  claim 77  in which the cartilage extracellular matrix is hyaline cartilage extracellular matrix or growth plate extracellular matrix. 
     
     
         80 . A multilayer scaffold suitable for repair of osteochondral defects in a mammal and having a first layer comprising a porous scaffold according to  claim 77  in which the cartilage extracellular matrix is hyaline cartilage extracellular matrix and a second layer comprising a porous scaffold according to  claim 77  in which the cartilage extracellular matrix is growth plate extracellular matrix, in which the first layer is attached to the second layer.