Nanofiber structures and methods of use thereof
Expanded, nanofiber structures are provided as well as methods of use thereof and methods of making.
1. A method for producing an expanded nanofiber or microfiber structure with increased porosity and thickness, said method comprising exposing the nanofiber structure or microfiber structure to a subcritical fluid and depressurizing, wherein said depressurization increases the porosity and thickness of the nanofiber structure or microfiber structure.
2. The method of claim 1 , wherein said subcritical fluid comprises CO 2 , N 2 , N 2 O, hydrocarbons, or fluorocarbons.
3. The method of claim 1 , wherein said subcritical fluid is subcritical CO 2 .
4. The method of claim 1 , wherein said exposure comprises immersing said nanofiber structure or microfiber structure in said subcritical fluid.
5. The method of claim 1 , wherein said nanofiber or microfiber structure comprises electrospun fibers.
6. The method of claim 1 , wherein said nanofiber or microfiber structure comprises a plurality of uniaxially-aligned nanofibers or microfibers, random nanofibers or microfibers, and/or entangled nanofibers or microfibers.
7. The method of claim 1 , further comprising preparing said nanofiber structure or microfiber structure comprising a plurality of nanofibers or microfibers prior to said exposure to the subcritical fluid.
8. The method of claim 1 , wherein said nanofibers or microfibers comprise hydrophilic polymers.
9. The method of claim 1 , wherein said nanofibers or microfibers comprise hydrophobic polymers.
10. The method of claim 9 , wherein said hydrophobic polymer is poly(caprolactone).
11. The method of claim 1 , wherein said nanofiber structure or microfiber structure comprises an active agent.
12. The method of claim 11 , wherein said active agent is selected from the group consisting of a therapeutic agent, a growth factor, a signaling molecule, a cytokine, a hemostatic agent, an antimicrobial, and an antibiotic.
13. The method of claim 11 , wherein said active agent is added to the nanofiber structure or microfiber structure after said exposure to the subcritical fluid.
14. The method of claim 1 , wherein the steps of i) exposing the nanofiber structure or microfiber structure to a subcritical fluid and ii) depressurizing, are performed more than once.
15. The method of claim 14 , wherein the steps of i) exposing the nanofiber structure or microfiber structure to a subcritical fluid and ii) depressurizing, are repeated 1 to 5 times.
16. The method of claim 1 , wherein said nanofiber or microfiber structure comprises an array of holes or wells.
17. The method of claim 1 further comprising crosslinking the nanofiber or microfiber structure.
18. The method of claim 16 , wherein said array of holes or wells has between 1 and 200 holes or wells.
19. The method of claim 16 , wherein each well or hole has a diameter of about 0.1 to about 5 mm.
20. The method of claim 1 , further comprising inserting or punching an array of holes or wells into said nanofiber or microfiber structure prior to said exposure to a subcritical fluid and depressurizing.