Properties of Gelatin/Carbonate Apatite Composite Compared to Bovine Bone
Bone is a composite of approximately 65% inorganic phase (carbonate apatite, CHA) and a 35% organic phase (mostly collagen). To date, several commercial composites consisting of natural or synthetic polymers and calcium phosphates ( hydroxyapatite, tricalcium phosphate, biphasic calcium phosphates) are recommended for use in bone repair. Objective: The aim of this study was to compare the physico-chemical properties of gelatin/carbonate apatite composites with that of bovine bone. Native (Gel) or cross-linked (Gel*) was used. Methods: The CHA was prepared by hydrolysis method. The gelatin (denatured collagen) was cross-linked using Genipin. The gelatin/CHA composite were prepared by mixing of 35% gelatin and 65% CHA and freeze-drying. The composites were characterized using x-ray diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM) and thermogravimetry (TGA). Dissolution properties were determined in acidic buffer (0.1M KAc, pH 6, 37°C). Mechanical strength was determined using 3-point bend test. Bovine bone was similarly characterized for comparison. Results: The composition and crystallite size of the CHA were similar to that of the bone mineral. The Gel/CHA and Gel*/CHA composites showed several physico-chemical properties (crystallinity, composition, thermal stability, mechanical strength, dissolution rate) similar to that of bone. Gel*/CHA compared to Gel/CHA composites showed lower elastic modulus, flexural strength, dissolution rate, swelling and higher porosity. Conclusion: The Gel*/CHA composites presented several properties similar to those of bovine bone and may have potential as bone substitute materials.
Kunio Ishikawa and Yukihide Iwamoto
P. Khanna and R. Z. LeGeros, "Properties of Gelatin/Carbonate Apatite Composite Compared to Bovine Bone", Key Engineering Materials, Vols. 529-530, pp. 413-416, 2013