Previous studies have stressed the importance of calcification of the polyethylene oxide (PEO) I polybutylene terephthalate (PBT) copolymer surface by establishing a direct relation with the occurrence of bone-bonding. Here, we characterized the morphology as well as the composition of this post-operative reaction product in PEOIPBT copolymers. X-ray · photoelectron spectroscopical results demonstrated the ability of PEOIPBT copolymers to rapidly adsorb calcium ions from fluids. After subcutaneous implantation in rats, it was shown that polymer calcification comprised plate-shaped crystals, whereas an electron-dense layer was frequently encountered at the interface. Cells with a characteristic morphology were directly apposed to abundantly calcified surfaces, indicating the biocompatible nature of the material. Subcutaneous calcification was composed of a carbonate-apatite structure with a crystallinity comparable to bone mineral as demonstrated by Fourier transformed infrared spectroscopy and X-ray diffraction.
It was concluded that the post-operative reaction product in PEOIPBT copolymers is, in morphology and composition, highly comparable to the carbonate-containing apatitic surface layer generated on acknowledged bioactive substrates and similar to the inorganic phase of bone apatite. This may, partially, explain the bone-bonding behaviour of PEOIPBT copolymers.
Radder, A. M.; Davies, J. E.; Sodhi, R. N. S.; van der Meer, S. A. T.; Wolke, J. G. C.; and van Blitterswijk, C. A.
"Post-Operative Carbonate-Apatite Formation in PEO/PBT Copolymers (Polyactive®),"
Cells and Materials: Vol. 5
, Article 5.
Available at: http://digitalcommons.usu.edu/cellsandmaterials/vol5/iss1/5