Shape Memory Silk Materials

Abstract

The present application relates to silk fibroin-based materials, methods for making and using the same. Provided materials exhibit shape memory characteristics while showing comparable or better volumetric swelling, biocompatibility and/or degradability when compared to current memory polymers derived from either natural or synthetic materials.

1 .- 94 . (canceled) 
     
     
         95 . A silk material having a structure characterized by:
 (i) interconnected, evenly spaced pores having rounded morphology;   (ii) substantial absence of negative imprints of ice crystals;   (iii) substantial uniformity of pore shape; or   (iv) combinations thereof,   wherein the structure is indistinguishable from a comparison structure made by cooling a silk fibroin solution at a cooling rate between −10° C./min to −0.001° C./min to a freezing temperature of less than or equal to −20° C., and   wherein the silk material is susceptible to compression into a compressed state of reduced volume relative to the material's initial volume prior to compression.   
     
     
         96 . The silk material of  claim 95 , wherein the material is characterized by volumetric expansion when exposed to a trigger and/or external stimulus following compression. 
     
     
         97 . The silk material of  claim 96 , wherein the volumetric expansion is at least two fold and/or about 400%. 
     
     
         98 . The silk material of  claim 96 , wherein the trigger is water, Phosphate Buffered Saline (“PBS”), Dulbecco's Modified Eagle's Medium (“DMEM”), bodily fluids, or combinations thereof,
 wherein the material remains compressed when dry and expands after immersion into the aqueous media. 
 
     
     
         99 . The silk material of  claim 95 , wherein the silk material comprises silk fibroin having an average molecular weight in a range between about 500 Da and about 3000 kDa. 
     
     
         100 . The silk material of  claim 95 , wherein the silk material comprises silk fibroin at a concentration within a range of about 0.1% to about 50%. 
     
     
         101 . The silk material of  claim 95  further comprising a plasticizer. 
     
     
         102 . The silk material of  claim 101 , wherein the plasticizer comprises one or more members selected from the group consisting of: glycerol, 1,2 Propanediol, 1,3 Propanediol, 1,4 Butanediol, 1,2,4 Butanetriol, Threitol, Erythritol, 1,2 Pentanediol, 1,5 Pentanediol, Adonitol, 1,2,6 Hexanetriol, and sugars. 
     
     
         103 . The silk material of  claim 101 , wherein the plasticizer is non-toxic. 
     
     
         104 . The silk material of  claim 101 , wherein the plasticizer is glucose, sorbitol, or mannitol. 
     
     
         105 . The silk material of  claim 101 , wherein a weight ratio of plasticizer: silk is between 0.05 and 0.8. 
     
     
         106 . The silk material of  claim 95 , wherein the silk fibroin is a modified silk fibroin, wherein the modified silk fibroin has between 5% and 75% of its tyrosine residues covalently modified. 
     
     
         107 . The silk material of  claim 106 , wherein the tyrosine residues are covalently modified with 4-sulfonic acid, 4-(heptyloxy)aniline, 4′-aminoacetophenone and combinations thereof. 
     
     
         108 . The silk material of  claim 95 , wherein the material is a foam, fiber, mesh, film, hydrogel, or combination thereof. 
     
     
         109 . The silk material of  claim 95 , wherein the silk material has an average pore diameter in a range between about 5 μm and about 500 μM. 
     
     
         110 . The silk material of  claim 95 , wherein the silk material is characterized in that when exposed to a compressive strain of up to 90%, the silk material recovers when exposed to the trigger without showing an indication of a plastic deformation. 
     
     
         111 . The silk material of  claim 95 , wherein the silk material further comprises an additive, agent, and/or functional moiety. 
     
     
         112 . The silk material of  claim 111 , wherein the additive, agent, and/or functional moiety comprises an anesthetic. 
     
     
         113 . An injectable composition comprising the silk material of  claim 95  and a carrier. 
     
     
         114 . A method of using a silk shape memory material, the method comprising steps of:
 subjecting a silk memory foam material to a compressive force so that it is compressed; and   exposing the compressed material to an environmental trigger so that it expands to form a silk sponge,   wherein the silk sponge has a volume comparable to that of the silk memory foam prior to compression and a structure characterized by:
 interconnected, evenly spaced pores having rounded morphology; 
 substantial absence of negative imprints of ice crystals; 
 substantial uniformity of pore shape; or 
 combinations thereof, and 
   wherein the structure is indistinguishable from a comparison structure made by cooling a silk fibroin solution at a cooling rate between −10° C./min to −0.001° C./min to a freezing temperature of less than −20° C.