Silk-based nanoimprinting

Abstract

Protein-protein imprinting of silk fibroin is introduced as a rapid, high-fidelity, and/or high-throughput method for the fabrication of nanoscale structures in silk films, through controlled manipulation of heat and/or pressure. High resolution imprinting on conformal surfaces is also demonstrated.

What is claimed is: 
     
         1 . A composition comprising:
 a first silk fibroin material comprising a predetermined nanostructure fabricated thereon; wherein the first silk fibroin material has a first beta sheet content and a first glass transition temperature (T g1 );   a second silk fibroin material, having a second beta sheet content and a second glass transition temperature (T g2 );   wherein the first silk fibroin material is in close contact with the second silk fibroin material, such that the predetermined nanostructure on the first fibroin material is substantially replicated onto the second silk fibroin material to produce an inverse imprint of the predetermined nanostructure.   
     
     
         2 . The composition of  claim 1 , wherein the inverse imprint of the predetermined nanostructure has a resolution of at least 200 nm. 
     
     
         3 . The composition of  claim 1 , wherein the inverse imprint of the predetermined nanostructure has a resolution of about 100 nm. 
     
     
         4 . A composition comprising:
 a first silk fibroin material comprising a predetermined nanostructure fabricated thereon; wherein the first silk fibroin material has a first water content and a first glass transition temperature (T g1 );   a second silk fibroin material, having a second water content and a second glass transition temperature (T g2 );   wherein the first silk fibroin material is in close contact with the second silk fibroin material, such that the predetermined nanostructure on the first fibroin material is substantially replicated onto the second silk fibroin material to produce an inverse imprint of the predetermined nanostructure.   
     
     
         5 . The composition of  claim 4 , wherein the inverse imprint of the predetermined nanostructure has a resolution of at least 200 nm. 
     
     
         6 . The composition of  claim 4 , wherein the inverse imprint of the predetermined nanostructure has a resolution of about 100 nm. 
     
     
         7 . A composition comprising:
 a plurality of negative silk fibroin imprints and a plurality of positive silk fibroin imprints;   wherein a positive silk fibroin imprint comprises a nanopattern, and wherein a negative silk fibroin imprint comprises an inverse of the nanopattern present on the positive silk fibroin imprint; and,   wherein the negative silk fibroin imprints are substantially replicas of one another, and wherein the positive silk fibroin imprints are substantially replicas of one another.   
     
     
         8 . A method comprising the steps of:
 (i) providing a crystallized silk fibroin master comprising a predetermined nanostructure thereon;   (ii) layering the crystallized silk fibroin master with a silk fibroin material having a high water content;   (iii) applying heat, pressure, or combination thereof, under a condition sufficient to generate an imprinted silk fibroin material having an inverse of the predetermined nanostructure.   
     
     
         9 . The method of  claim 8 , further comprising
 (iv) annealing the imprinted silk fibroin material from step (iii) to induce crystallization.   
     
     
         10 . The method of  claim 8 , further comprising using the imprinted silk fibroin material from step (iii) as a template for repeating steps (i) and (ii). 
     
     
         11 . A method for high throughput imprinting comprising repeating the method of  claim 8 . 
     
     
         12 . The method of  claim 10 , wherein the repeating is performed about 2-30 rounds. 
     
     
         13 . The method of any one of  claims 8 - 12 , wherein the high water content is at least 95%. 
     
     
         14 . The method of  claim 13 , wherein the high water content is at least 99%. 
     
     
         15 . The method of any one of  claims 8 - 14 , wherein the condition comprises heating for a duration of about 2 seconds to 120 seconds. 
     
     
         16 . The method of any one of  claims 8 - 15 , wherein the condition comprises heating at about 75° C. to 130° C. 
     
     
         17 . The method of any one of  claims 8 - 16 , wherein the condition comprises heating for a duration of about 5 seconds at about 120° C. 
     
     
         18 . The method of any one of  claims 8 - 17 , wherein the condition comprises heating for a duration of about 30 seconds at about 100° C. 
     
     
         19 . The method of any one of  claims 8 - 18 , wherein the condition comprises heating for a duration of about 60 seconds at about 80° C. 
     
     
         20 . The method of any one of  claims 8 - 19 , wherein the condition comprises applying pressure at about 10-100 PSI. 
     
     
         21 . The method of any one of  claims 8 - 20 , used for conformal imprinting. 
     
     
         22 . The method of any one of  claims 8 - 21 , wherein the step (iii) is performed with the use of an embosser.