Rapidly Resorbable, Temporarily Mechanically Stable Composites for Bone Replacement
This study describes the preparation of a composite material  from synthetic nano-scaled hydroxyapatite (nHA) and a gelatin matrix (80% nHA, 20% gelatin). This composite material is intended to extend the range of biological hydroxyapatite-based defect-filling materials for bone replacement. Ostim® (aqueous suspension of nHA having a crystallite size of about 20nm) was used as the inorganic component whereas porcine gelatin (type A, 180 Bloom) composed the organic part. Both components were homogenized during a spray-drying process. Cylindrical samples of the spray-dried granulate (HG 80/20) produced by pressing had adequate mechanical stability for storage, transport and handling in the surgery. The flexural strengths for the samples were determined on dry samples as well as after storing in media (distilled water, SBF solution) for 60 minutes. After staying 30 minutes in a SBF solution or in water, flexural strength dropped off about 30% while the shape of the sample was retained. Temperature treatments of both granulate and pressed samples resulted in reduction of the sample swelling from 70vol-% to 50vol-%. The sample produced by pressing can be machined (turned, drilled, milled).
Marcelo Prado and Cecília Zavaglia
N. Bielefeldt et al., "Rapidly Resorbable, Temporarily Mechanically Stable Composites for Bone Replacement", Key Engineering Materials, Vols. 396-398, pp. 469-472, 2009