Calcium phosphate/structural protein composites and method of preparation thereof
Ceramic/structural protein composite scaffolds and their preparation in a simple one-step process are shown.
1. A method of forming a composite scaffold, the method comprising:
forming an aqueous scaffold system comprising a structural protein, a weak acid, water, Ca 2+ , HPO 4 2− , Mg 2+ , Na + , K + , Cl − , SO 4 2− , HCO 3 − , and a buffer system, wherein the aqueous scaffold system has an initial pH of 6.5 to 8.0 and wherein in the aqueous scaffold system:
the structural protein is collagen Type I, II, Ill, or V present in an amount of about 0.1 g/L to about 5.0 g/L
the Ca 2+ is present in an amount of about 3.0 to about 15.0 mM,
the HPO 4 2− is present in an amount of about 3.0 to about 10.0 mM
the Mg 2+ is present in an amount of about 0.05 to about 5.0 mM,
the Na + is present in an amount of about 5.0 to about 300.0 mM,
the K + is present in an amount of about 0.1 to about 10.0 mM,
the Cl − is present in an amount of about 5.0 to about 300.0 mM,
the SO 4 2− is present in an amount of about 0 to about 2.0 mM,
the HCO 3 − is present in an amount of about 0.5 to about 30.0 mM;
forming a calcium phosphate-structural protein composite by the simultaneous co-precipitation of calcium phosphate and structural protein from the aqueous scaffold system, wherein the calcium phosphate is precipitated on the surface of fibers of the structural protein;
isolating the calcium phosphate-structural protein composite;
freeze-drying the isolated calcium phosphate-structural protein composite to form a calcium phosphate-structural protein composite scaffold.
2. The method of claim 1 , wherein the collagen content in the composite scaffold is about 10 to about 90 weight percent based on the total weight of the composite scaffold.
3. The method of claim 1 , further comprising molding the isolated calcium phosphate-structural protein composite prior to freeze-drying.
4. The method of claim 1 , wherein the weak acid has a pKa of about 3.5 to about 5.5.
5. The method of claim 1 , further comprising adding a crosslinking agent to crosslink the calcium phosphate-structural protein composite prior to isolating.
6. The method of claim 1 , further comprising placing the aqueous scaffold system in a container wherein the container is sealed prior to allowing the calcium phosphate-structural protein composite to form.
7. The method of claim 1 , wherein the collagen content in the composite scaffold is 50 to about 90 weight percent based on the total weight of the composite scaffold.
8. A method of forming a composite scaffold, the method consisting of:
forming an aqueous scaffold system comprising a structural protein, a weak acid, water, Ca 2+ , HPO 4 2− , Mg 2+ , Na + , K + , Cl − , SO 4 2− , HCO 3 − , and a buffer system, wherein the aqueous scaffold system has an initial pH of 6.5 to 8.0 and wherein in the aqueous scaffold system:
the structural protein is collagen Type I, II, Ill, or V present in an amount of about 0.1 g/L to about 5.0 g/L
the Ca 2+ is present in an amount of about 3.0 to about 15.0 mM,
the HPO 4 2− is present in an amount of about 3.0 to about 10.0 mM
the Mg 2+ is present in an amount of about 0.05 to about 5.0 mM,
the Na + is present in an amount of about 5.0 to about 300.0 mM,
the K + is present in an amount of about 0.1 to about 10.0 mM,
the Cl − is present in an amount of about 5.0 to about 300.0 mM,
the SO 4 2− is present in an amount of about 0 to about 2.0 mM,
the HCO 3 − is present in an amount of about 0.5 to about 30.0 mM;
forming a calcium phosphate-structural protein composite by the simultaneous co-precipitation of calcium phosphate and structural protein from the aqueous scaffold system, wherein the calcium phosphate is precipitated on the surface of fibers of the structural protein;
optionally adding a crosslinking agent to crosslink the calcium phosphate-structural protein composite;
isolating the calcium phosphate-structural protein composite;
optionally molding the isolated calcium phosphate-structural protein composite; and
freeze-drying the isolated calcium phosphate-structural protein composite to form a calcium phosphate-structural protein composite scaffold.