Porous composite scaffolds based on gelatin and partially hydrolyzed α-tricalcium phosphate

Porous composite scaffolds of varying compositions were prepared by freeze-drying gelatin foams containing increasing amounts of alpha-tricalcium phosphate (alpha-TCP), up to about 40 wt.%. Due to the presence of gelatin, a partial hydrolysis of alpha-TCP into octacalcium phosphate (OCP) occurs during foaming. As a consequence, the scaffolds contain both alpha-TCP and OCP, in relative amounts of about 74% and 26%, respectively, independent of the initial composition. In physiological conditions the inorganic component of the scaffolds undergoes a further hydrolysis as shown by the finding that after immersion in phosphate-buffered saline at 37 degrees C for 1 week the scaffolds contain poorly crystalline hydroxyapatite together with OCP. The scaffolds display a porous interconnected microstructure. The mean dimensions of the pores decrease from about 350 to about 170 mu m as the inorganic phase content increases. Simultaneously, the mean values of the compression strength and Young's modulus increase. Stabilization of the scaffolds was obtained by using a natural, nontoxic, crosslinking agent, genipin, which significantly improves their mechanical properties. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.