Hydroxyapatite Scaffolds Produced by Hydrothermal Deposition of Monetite on Polyurethane Sponges Substrates
Hydroxyapatite scaffolds have been being produced by a wide range of processes. The optimun material to be used as bone graft has to be partially resorbable, with resorption rates similar to new bone formation ones. The samples must have porosity compatible with tissue ingrowth. Hydroxyapatite and tricalcium phosphate ceramics are good choices for designing such materials. In the present study, polymeric sponges were coated with hydroxyapatite and sintered. The method consists of coating polyurethane sponges substrates in an aqueous solution rich in phosphate (PO4)3- and calcium (Ca)2+ ions. The solution is composed by 0.5M Ca(OH)2, 0.3M H3PO4 and 1M CH3CHCO2HOH (lactic acid) at pH of 3.7. The sponges were immersed in a beaker with the solution and heated up to 80°C to precipitate monetite on the sponge. Continuous and adherent coatings were formed on the surface of sponges interconections. These coatings were characterised by X-ray diffractometry and the only identified phase was monetite. The substrates were converted to hydroxyapatite in an alkali solution.The total conversion from monetite to hydroxyapatite was confirmed by XRD analyses. The struts were heat treated in order to eliminate the organic sponge and sinter the scaffolds. After sintering, hydroxyapatite and tricalcium phosphate were identified on the struts. Optical microscopy revealed the morphology of the struts, while scanning electron microscopy (SEM) showed the precipitates morphology. The method showed to be efficient in the production of porous scaffolds.
Eyup Sabri Kayali, Gültekin Göller and Ipek Akin
F. D. Mishima et al., "Hydroxyapatite Scaffolds Produced by Hydrothermal Deposition of Monetite on Polyurethane Sponges Substrates", Key Engineering Materials, Vols. 493-494, pp. 820-825, 2012