In-vitro-Biokompatibilitätstestung modifizierter Apatit- und Oxidkeramiken in der humanen Osteoblastenzellkultur
Presently available bone substitute materials are either bioactive with poor biomechanical stability or they show good biomechanical impact, but are bioinert. The aim of this study was to combine bioactivity of hydroxyapatite (HA) and the mechanical properties of bioinert ceramics like yttrium oxide by creating composites. To evaluate their bioactivity and biocompatibility we examined in a first group osteoblastic responses to pure ceramics: hydroxyapatite (HA), fluorapatite (FA) and tricalcium phosphate (TCP), as well as composites: FA/HA, yttriumoxide/HA and pure yttrium oxide (Y2O3) in vitro. In a second group we examined different stabilizers (calcium-, cer- yttrium and magnesiumoxide) of zirkonoxide to evaluate if there are any differences in bioactivity or cytotoxicity. In the third group we developed a method to activate the surface of the ceramics by treating them with sodium hydroxyde. We expected to create OH- at the surface on which cells adhere better. Human Osteoblast-like cells were obtained from trabecular bone fragments of patients undergoing knee surgery. 1x10 4 cells were cultured on each ceramic described above. We determined the material’s effect on cell adhesion, proliferation and protein secretion after 24 hours and seven days of cultivation. Trypan blue was used to desperate dead and living cells on the ceramic surface. Alkaline phosphatase and osteocalcin secretion as markers of bone formation were measured. Cell morphology and mineralisation were examined using special stainings. Apoptosis was determined using a nick end labelling technique. Cell proliferation and differentiation on HA and TCP were quite good. Apoptosis could hardly be detected. FA and the composite FA/HA showed similar results concerning the examined parameters. Y2O3 had the lowest cell counts both after one day and one week. The apoptosis rate was high (up to 25 %). In the second group we found no difference between the stabilisation of zirkonoxide with calcium-, cer- or magnesiumoxide. All of them showed quite good results. In the third group we showed that sodium hydroxyde does improve bioactivity as all parameters of the modified ceramics were above the pure ones. We showed that there are some ceramics which could be interesting bone substitute materials in future. But further studies are needed.
info:eu-repo/classification/ddc/610, Medizin, Knochenersatzmaterialien, Biokompatibilitätstestung
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