Graft scaffold for cartilage repair and process for making same

Abstract

The present invention relates to a method of providing a graft scaffold for cartilage repair, particularly in a human patient. The method of the invention comprising the steps of providing particles and/or fibres; providing an aqueous solution of a gelling polysaccharide; providing mammalian cells; mixing said particles and/or fibres, said aqueous solution of a gelling polysaccharide and said mammalian cells to obtain a printing mix; and depositing said printing mix in a three-dimensional form. The invention further relates to graft scaffolds and grafts obtained by the method of the invention.

We claim: 
     
         1 . A graft scaffold obtainable by, or obtained by a method comprising:
 providing an aqueous solution of a gelling polysaccharide selected from the group consisting of gellan gum, acylated and sulfated gellan gum;   providing at least one of:
 particles and/or fibres and 
 mammalian cells; 
   mixing said aqueous solution of a gelling polysaccharide, said particles and/or fibres, and/or said mammalian cells to obtain a printing mix; and   depositing said printing mix in a three-dimensional form,   
       wherein said solution has a concentration of 1% to 6% (w/v) of said gelling polysaccharide, wherein said solution of a gelling polysaccharide further comprises alginate; and 
       wherein the graft scaffold comprises a) said gelling polysaccharide; b) at least one of said particles and/or said fibers and/or said mammalian cells; and c) alginate. 
     
     
         2 . The graft scaffold of  claim 1 , wherein said solution has a concentration of 3% to 3.5% (w/v) of said gelling polysaccharide. 
     
     
         3 . The graft scaffold of  claim 1 , wherein the alginate concentration is 2.5% or 3% (w/v). 
     
     
         4 . The graft scaffold of  claim 1 , wherein said gelling polysaccharide is acylated gellan gum. 
     
     
         5 . The graft scaffold of  claim 1 , wherein said aqueous solution of a gelling polysaccharide further comprises between 10 and 150 mmol/l of divalent ions. 
     
     
         6 . The graft scaffold of  claim 1 , wherein both mammalian cells and at least one of particles and fibres are provided for obtaining said printing mix. 
     
     
         7 . The graft scaffold of  claim 1 , wherein only mammalian cells are provided for obtaining said printing mix. 
     
     
         8 . The graft scaffold of  claim 1 , wherein said solution of a gelling polysaccharide further comprises a monosaccharide sugar or disaccharide sugar at physiologic osmolarity. 
     
     
         9 . The graft scaffold of  claim 1 , wherein a growth factor and/or a mitogenic factor is provided within the printing mix. 
     
     
         10 . The graft scaffold of  claim 9 , wherein the growth factor or mitogenic factor is selected from the group consisting of BMP-2, BMP-7, TGF-β1, TGF-β2, TGF-β3, FGF-2, and IGF-1. 
     
     
         11 . The graft scaffold of  claim 9 , wherein the concentration of growth factors is 0.1-5 ng/ml, 5-50 ng/ml or 50-500 ng/ml. 
     
     
         12 . The graft scaffold of  claim 1 , wherein said mammalian cells are cartilage cells, cartilage stem cells, or cartilage precursor cells. 
     
     
         13 . The graft scaffold of  claim 1 , wherein said mammalian cells are present at concentrations of 3×10 6  cells/ml-50×10 6  cells/ml. 
     
     
         14 . The graft scaffold of  claim 1 , wherein said printing mix comprises 10 ng/ml TGF beta 3. 
     
     
         15 . The graft scaffold of  claim 1 , wherein depositing said printing mix in a three-dimensional form is performed by deposition of lines of said printing mix, wherein each line has a width of 700 to 1100 μm and said lines overlap by 20% to 60%. 
     
     
         16 . The graft scaffold of  claim 1 , wherein said depositing is performed by 3-D-printing methods. 
     
     
         17 . The graft scaffold of  claim 1 , wherein said depositing is performed by additive manufacturing methods. 
     
     
         18 . The graft scaffold of  claim 17 , wherein the additive manufacturing method is ink jet printing, bioprinting, extrusion printing or layer-by-layer method. 
     
     
         19 . The graft scaffold of  claim 1 , wherein the 3-Dimensional form is generated based on a computer model of a contralateral organ of said human patient.