Methods and compositions for bone graft implants

Abstract

An autologous platelet gel for bone grafts is comprised of a mixture of platelet-rich-plasma activated by calcium chloride solution, and an aqueous suspension of partially frayed Type I collagen.

What is claimed:  
     
         1 . An autologous gel, comprising; an aqueous suspension of Type I fibrillar collagen alkaline treated to created partially frayed termini; calcium chloride; and platelet-rich-plasma processed to form an in vitro formable matrix.  
     
     
         2 . A method of making an implant gel, comprising the steps of: making (( an admixture of Type I collagen in physiological suspension, an aqueous ( solution of calcium chloride and bone particulate; and adding to said admixture platelet-rich-plasma in an amount sufficient to establish a viscous formable gel.  
     
     
         3 . The method as recited in  claim 2  including the step of heating said gel at around body temperature to accelerate formation of the gel.  
     
     
         4 . In a platelet-based sealant characterized by a mixture of calcium chloride, thrombin and a source of platelets, the improvement comprising: substituting an effective amount of terminally frayed Type I microfibrillar collagen for said thrombin.  
     
     
         5 . A cellular matrix for cellular moieties, comprising by volume 10 to 60 parts of platelet-rich-plasma; 1 to 5 parts calcium chloride; 5 to 60 parts of partially defibrillated Type I collagen; and 5 to 40 parts bone particulate.  
     
     
         6 . A method of making an in-vitro thrombic agent for use in platelet-rich-plasma compositions comprising the steps of: forming a mixture of Type I fibrillar collagen and water; adjusting the mixture to a pH in the range of about 8 to 12; stirring said mixture at said range for a sufficient time to establish a stable suspension; and readjusting the suspension to a pH in the physiological range.  
     
     
         7 . The method as recited in  claim 7  wherein said mixture has a pH in the range of 9.5 to 110 and said physiological range is between 6.8 and 7.2.  
     
     
         8 . A method of separating from whole blood a predominantly platelet-rich-plasma fraction comprising the steps of: centrifuging a volume of whole blood at a first separating condition at centrifugal forces in the range of about 150 g to 400 g and a time sufficient to differentiate a top layer, a middle layer and a bottom layer; separating said top layer and said middle layer from said bottom layer; recentrifuging the top layer and the middle layer at a second separating condition at centrifugal forces in the range of about 225 g to 300 g for a time to differentiate further said top layer from said middle layer; and separating said middle layer from said top layer.  
     
     
         9 . The method as recited in  claim 9  wherein said centrifugal forces in at said first separating condition are in the range of about 175 g to 250 g.  
     
     
         10 . The method as recited in  claim 9  wherein said centrifugal forces at said second separating condition are in the range of about 225 g to 275 g.  
     
     
         11 . A cellular matrix comprising: a cellular moiety in admixture with an autologous platelet-based gel including autologous platelet-rich-plasma, terminally frayed microfibrillar Type I collagen, and a gelling initiator.  
     
     
         12 . The matrix as recited in  claim 11  wherein said cellular moiety is pancreatic islets.