Glass scaffolds with controlled resorption rates and methods for making same

Abstract

The present invention relates to resorbable glass scaffolds for use in biological applications and methods for making same. Specifically, these scaffolds are composed of phosphate glass fibers, where the rate of dissolution into biological fluids is controlled by the length of time the glass is held above its melt temperature prior to spinning the fiber.

1 . A scaffold used in repairing an injury to bone or cartilage, comprising: 
 a first glass fiber and a second glass fiber, each having the same glass composition, but different resorption rates, a resorption rate of said first glass fiber attributable to a first melt hold time    a first amount of said glass composition is maintained in a melted state to confer a first resorption rate to said first amount of said glass composition, the first resorption rate being matched to a predetermined rate of bone growth into the scaffold,    said first glass fiber being formed from said first amount of said glass composition into a resorbable fiber having the first resorption rate, a resorption rate of said second glass fiber attributable to a second melt hold time,    a second amount of said glass composition is maintained in a melted state to confer a second resorption rate to said second amount of said glass composition, the second resorption rate being slower than the first resorption rate,    said second glass fiber being formed from said second amount of said glass composition into a second resorbable fiber having the second resorption rate,    said first resorbable fiber and said second resorbable fiber being included in said scaffold, said first resorbable fiber being resorbable to promote bone in-growth while said second resorbable fiber persists for a predetermined time in order to maintain structural support for the scaffold.    
     
     
         2 . The scaffold of  claim 15 , wherein said first and said second fibers form a composite textile structure.  
     
     
         3 . The scaffold of  claim 15 , wherein said first and second fibers have a diameter in a range of from about 1 μm to about 100 μm.  
     
     
         4 . The scaffold of  claim 15 , wherein said glass composition is a phosphate glass composition.  
     
     
         5 . The scaffold of  claim 4 , wherein said glass composition includes CaO, Fe 2 O 3  and P 2 O 5  in a molar ratio of approximately 16.5:33.5:50.0.  
     
     
         6 . The scaffold of  claim 4 , wherein said glass composition includes CaO, Fe 2 O 3  and P 2 O 5  in approximately the following range of molar ratios (CaO) 16.5 to 33.5: (Fe 2 O 3 ) 16.5 to 33.5: (P 2 O 5 ) 50.0.  
     
     
         7 . The scaffold of  claim 1 , wherein the first melt hold time and the second melt hold time are each in the range of from about 8 hours to about 72 hours.  
     
     
         8 . The scaffold of  claim 2 , wherein said composite textile structure results in a spacial distribution of each of said first and second fibers.  
     
     
         9 . The scaffold of  claim 2 , wherein said first and second fibers have approximately the same diameter.  
     
     
         10 . The scaffold of  claim 2 , further including a resorbable matrix material to combine with the composite textile structure to form said scaffold.  
     
     
         11 . The scaffold of  claim 10 , wherein said matrix material is selected from the group consisting of: resorbable synthetic polymers, biopolymers, ceramics and photocurable polymers.  
     
     
         12 . The scaffold of  claim 10 , further comprising bone growth agents in the matrix material.  
     
     
         13 . The scaffold of  claim 10 , further comprising a medicament in the matrix to enable controlled release of said medicament.  
     
     
         14 . (canceled)  
     
     
         15 . A tissue replacement scaffold, comprising a plurality of resorbable glass fibers made from the same composition, a first of said plurality having a resorption rate greater than a second of said plurality, said first and second fibers having the resorption rate thereof controlled by the duration that the glass from which said first and second fibers are formed is held in a melted state.  
     
     
         16 . The scaffold of  claim 15 , wherein said resorption rate of said first fiber approximately matches the rate of cellular ingrowth.  
     
     
         17 . The scaffold of  claim 15 , further comprising a bone growth agent incorporated therein.  
     
     
         18 . The scaffold of  claim 15 , further comprising a polymer matrix material disposed about said fibers.  
     
     
         19 . The scaffold of  claim 18 , further including a medicament incorporated therein, the resorption rate of said scaffold determining the controlled rate of release of said medicament.  
     
     
         20 . The scaffold of  claim 1 , wherein said fibers are formed into a textile structure.