Modified porous materials and methods of creating interconnected porosity in materials
Techniques, mixtures and improved porous materials (interconnected porous constructs) that are capable of maintaining a sufficient porosity while conferring improved mechanical and physical strength to the final construct. A sacrificial construct (for example, a sacrificial material such as polymethyl methacrylate (PMMA)) is used to obtain an inverse porosity of the construct it was molded into. The process provides a less porous end material that may be used as an arthroplasty device or surgical implant (for example, an interference screw of suture anchor) among many other applications. The process employs a sacrificial material to reduce the porosity of the final construct to about 35%.
1. A method of producing a porous structure, comprising the steps of:
merging a plurality of soluble particles using a solvent to form a porous construct of merged soluble particles;
applying a first non-soluble material to the merged soluble particles;
curing the first non-soluble material and the merged soluble particles;
dissolving the merged soluble particles to produce interconnected pores throughout at least a volumetric portion of the first non-soluble material forming a porous construct;
applying a second non-soluble material to the porous construct;
curing the second non-soluble material and the porous construct; and
dissolving the porous construct to produce a porous structure formed of the second non-soluble material.
2. The method of claim 1 , wherein the soluble particles are formed of poly(vinyl alcohol).
3. The method of claim 1 , wherein the first non-soluble material is polymethyl methacrylate.
4. The method of claim 1 , wherein the second non-soluble material is a polymer.
5. The method of claim 4 , wherein the second non-soluble material is selected from the group consisting of PLLA (poly-L-lactic acid), PLA (poly lactic acid), PLGA (co-poly lactic acid/glycolic acid), PGL (polyglycerol), PCL (caprolactone) and PGA (polyglycolic acid).
6. The method of claim 5 , wherein the second non-soluble material is poly-L-lactic acid).
7. The method of claim 1 , wherein the plurality of soluble particles are water soluble.
8. The method of claim 7 , wherein the soluble particles are dissolved at a temperature below the Tg° of the first non-soluble material.
9. The method of claim 1 , wherein the plurality of soluble particles are merged in the presence of an inorganic acid.
10. The method of claim 9 , wherein the inorganic acid is a phosphoric acid compound.
11. The method of claim 10 , wherein the inorganic acid comprises about 5% phosphoric acid and about 95% water.
12. The method of claim 1 , wherein the porous construct is dissolved with an organic solvent.
13. The method of claim 12 , wherein the organic solvent is an alcohol, an ether-group solvent or a vinyl-group solvent.
14. A method of forming a porous material, comprising the steps of:
creating a porous soluble structure from a soluble material;
filling a void area of the soluble porous structure with a non-soluble material;
curing the soluble porous structure and the non-soluble material;
removing the soluble porous structure to obtain a newly-formed porous structure having the non-soluble material;
filling the void area of the newly-formed soluble porous structure with another non-soluble material; and
removing the non-soluble material to obtain a porous material having the another non-soluble material.
15. The method of claim 14 , wherein the soluble porous structure is formed of poly(vinyl alcohol).
16. The method of claim 14 , wherein the non-soluble material is polymethyl methacrylate.
17. The method of claim 14 , wherein the another non-soluble material is poly-L-lactic acid).
18. A porous interconnect structure formed by the method of claim 1 .
19. The porous interconnect structure of claim 18 , wherein the porosity of the interconnect structure is about 35%.