Controlled cross-linking processing of proteins
A method of forming a cross-linked protein structures includes preparing a solution of protein dissolved in a benign solvent and forming an intermediate protein structure from the solution. The intermediate protein structure can be cross-linked by providing for a specific ratio of chemical cross-linking agents to form the cross-linked protein structure. The solution can be prepared by adding a cross-linker of N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) at a ratio of two-to-one of NHS to EDC to alcohol. PBS buffer (20×) can be added to the solution until the volume ratio of PBS buffer (20×) to alcohol is about one-to-one. About 16 percent by weight of protein can be dissolved in the solution. The solution can be electrospun to form an intermediate protein structure. After a period of time, the protein structure can be cross-linked to form the cross-linked protein structure.
1. A method of forming a cross-linked protein structure, comprising:
forming a protein solution by dissolving a protein in a solution of water, salt, alcohol, and a cross-linker, wherein the cross-linker is N-hydroxysuccinimide (“EDC”) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (“NHS”), and the protein is collagen;
forming an intermediate protein structure from the protein solution; and
after a period of time has elapsed, cross-linking at least a portion the intermediate protein structure to form the cross-linked protein structure.
2. The method of claim 1 , wherein the molar ratio of NHS to EDC is about 1:1.
3. The method of claim 1 , wherein the intermediate protein structure is formed by an electrospinning process.
4. The method of claim 1 , wherein the intermediate protein structure is formed by an electrospraying process.
5. The method of claim 1 , wherein the intermediate protein structure is formed by a gravitational feed process.
6. The method of claim 1 , wherein the collagen dissolved in the solution is less than about 25 percent by weight.
7. The method of claim 6 , wherein the collagen dissolved in the solution is about 16 percent by weight.
8. The method of claim 1 , wherein the cross-linker is EDC and NHS, and the protein is gelatin.
9. The method of claim 8 , wherein the molar ratio of NHS to EDC is 1:1.
10. The method of claim 8 , wherein the intermediate protein structure is formed by an electrospinning process.
11. The method of claim 8 , wherein the intermediate protein structure is formed by an electrospraying process.
12. The method of claim 8 , wherein the intermediate protein structure is formed by a gravitational feed process.
13. The method of claim 8 , wherein the gelatin dissolved in the solution is less than about 25 percent by weight.
14. The method of claim 13 , wherein the gelatin dissolved in the solution is about 16 percent by weight.