Scaffolds formed from polymer-protein conjugates, methods of generating same and uses thereof

Abstract

Conjugates are provided herein which comprise a protein attached to at least two polymeric moieties, at least one of which exhibits reverse thermal gelation. The conjugates are suitable for being cross-linked by non-covalent and/or covalent cross-linking. Compositions-of-matter comprising cross-linked conjugates are provided herein, as well as processes for producing same. Methods of controlling a physical property of compositions-of-matter are also provided herein. The conjugates and compositions-of-matter may be used for various applications, such as cell growth, tissue formation, and treatment of disorders characterized by tissue damage or loss, as described herein.

What is claimed is: 
     
         1 . A conjugate comprising a polypeptide having attached thereto at least two polymeric moieties, at least one of said polymeric moieties exhibiting a reverse thermal gelation. 
     
     
         2 . The conjugate of  claim 1 , wherein each of said polymeric moieties exhibits a reverse thermal gelation. 
     
     
         3 . The conjugate of  claim 1 , wherein said polypeptide comprises a fibrinogen or a fragment thereof. 
     
     
         4 . The conjugate of  claim 1 , wherein at least one of said polymeric moieties comprises a poloxamer (poly(ethylene oxide-propylene oxide) copolymer). 
     
     
         5 . A composition-of-matter comprising a cross-linked form of the conjugate of  claim 1 , said cross-linked form comprising a plurality of molecules of the conjugate cross-linked to one another. 
     
     
         6 . The composition-of-matter of  claim 5 , being a hydrogel. 
     
     
         7 . The composition-of-matter of  claim 5 , generated by a reverse thermal gelation of said plurality of molecules of the conjugate in an aqueous solution. 
     
     
         8 . The composition-of-matter of  claim 5 , wherein said plurality of molecules of the conjugate are non-covalently cross-linked to one another. 
     
     
         9 . The composition-of-matter of  claim 5 , wherein at least one of said polymeric moieties further comprises a cross-linking moiety, and said plurality of molecules of the conjugate are covalently cross-linked to one another. 
     
     
         10 . The composition-of-matter of  claim 5 , further comprising cells therein. 
     
     
         11 . The composition-of-matter of  claim 5 , further comprising growth factors. 
     
     
         12 . A process of producing the composition-of-matter of  claim 5 , the process comprising heating a solution of a plurality of molecules of a conjugate comprising a polypeptide having attached thereto at least two polymeric moieties, at least one of said polymeric moieties exhibiting a reverse thermal gelation, from a first temperature to a second temperature, said second temperature being such that a reverse thermal gelation of the conjugate in said solution is effected, thereby producing the composition-of-matter. 
     
     
         13 . The process of  claim 12 , wherein said composition-of-matter is produced in vivo. 
     
     
         14 . The process of  claim 13 , wherein said solution further comprises cells derived from an autologous source. 
     
     
         15 . A process of producing the composition-of-matter of  claim 9 , the process comprising subjecting a solution comprising a plurality of molecules of a conjugate comprising a polypeptide having attached thereto at least two polymeric moieties, at least one of said polymeric moieties exhibiting a reverse thermal gelation, at least one of said polymeric moieties further comprising at least one cross-linking moiety for covalently cross-linking a plurality of molecules of the conjugate to one another, to conditions that effect covalent cross-linking of said cross-linking moieties, thereby producing the composition-of-matter. 
     
     
         16 . The process of  claim 15 , wherein said covalent cross-linking is effected in vivo. 
     
     
         17 . The process of  claim 16 , wherein said solution further comprises cells derived from an autologous source. 
     
     
         18 . A process of producing the composition-of-matter of  claim 9  in vivo, the process comprising:
 (a) subjecting a solution comprising a plurality of molecules of a conjugate comprising a polypeptide having attached thereto at least two polymeric moieties, at least one of said polymeric moieties exhibiting a reverse thermal gelation, at least one of said polymeric moieties further comprising at least one cross-linking moiety for covalently cross-linking a plurality of molecules of the conjugate to one another, to conditions that effect covalent cross-linking ex vivo, to thereby produce a covalently cross-linked scaffold; and 
 (b) subjecting said covalently cross-linked scaffold to a physiological temperature in vivo, such that a reverse thermal gelation of said scaffold is effected in vivo, thereby producing the composition-of-matter. 
 
     
     
         19 . The process of  claim 18 , wherein said solution further comprises cells derived from an autologous source. 
     
     
         20 . A method of inducing formation of a tissue in vivo, the method comprising implanting the composition-of-matter of  claim 5  in a subject, to thereby induce the formation of the tissue. 
     
     
         21 . The method of  claim 20 , wherein said composition-of-matter further comprises cells derived from said subject. 
     
     
         22 . The method of  claim 20 , wherein said composition-of-matter further comprises growth factors. 
     
     
         23 . The method of  claim 20 , wherein said tissue is cartilage. 
     
     
         24 . A method of inducing formation of a tissue in vivo, the method comprising implanting a plurality of molecules of the conjugate of  claim 1  in a subject, to thereby induce the formation of the tissue. 
     
     
         25 . The method of  claim 24 , further comprising implanting in said subject cells derived from said subject in combination with said plurality of molecules of the conjugate. 
     
     
         26 . The method of  claim 24 , wherein said tissue is cartilage. 
     
     
         27 . A method of treating a subject having a disorder characterized by tissue damage or loss, the method comprising implanting the composition-of-matter of  claim 5  in a subject, to thereby induce formation of said tissue, thereby treating the disorder characterized by tissue damage or loss. 
     
     
         28 . The method of  claim 27 , wherein said composition-of-matter further comprises cells derived from said subject. 
     
     
         29 . The method of  claim 27 , wherein said composition-of-matter further comprises growth factors. 
     
     
         30 . The method of  claim 27 , wherein said disorder is an articular cartilage defect. 
     
     
         31 . A method of treating a subject having a disorder characterized by tissue damage or loss, the method comprising implanting a plurality of molecules of the conjugate of  claim 1  in a subject, to thereby induce formation of said tissue, thereby treating the disorder characterized by tissue damage or loss. 
     
     
         32 . The method of  claim 31 , further comprising implanting in said subject cells derived from said subject in combination with said plurality of molecules of the conjugate. 
     
     
         33 . The method of  claim 31 , wherein said disorder is an articular cartilage defect.