Dissolution control and cellular responses of calcium phosphate coatings on zirconia porous scaffold.
Different types of calcium phosphates [hydroxyapatite (HA), fluorapatite (FA), tricalcium phosphate (TCP), and their composites (HA + FA, HA + TCP)] were coated on a zirconia (ZrO(2)) porous scaffold using a powder slurry method. The ZrO(2) porous scaffold was intended for a load-bearing implant, and the apatite layers were coated to improve osteoconductivity. The insertion of an FA intermediate layer between the coating layer and ZrO(2) scaffold effectively suppressed the reaction between the calcium phosphate and ZrO(2) and maintained the coating layer at the initial powder composition. The obtained coating layer, of a thickness of approximately 30 microm, was relatively microporous and firmly adherent to the ZrO(2) scaffold. Dissolution tests in physiological solution showed typical differences depending on the coating layers, with the dissolution rate increasing in the order TCP > HA + TCP > HA > HA + FA > FA. This result suggests the functional coating of the calcium phosphates in view of tailoring the solubility. Osteoblast-like cells, MG63 and HOS, responded similarly in terms of cell growth, morphology, and proliferation rate regardless of the coating types, indicating favorable and comparable cell viability. However, the alkaline phosphatase (ALP) activity of the cells on the pure HA and HA composite coatings (HA + FA and HA + TCP) expressed at higher levels compared to those on pure FA and pure TCP coatings for both MG63 and HOS cells, suggesting a selective cell activity depending on the coating types. All the calcium phosphate-coated-ZrO(2) scaffolds showed higher ALP levels compared to pure ZrO(2) scaffold.
Kim
Hae-Won
HW
School of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea.
Kim
Hyoun-Ee
HE
Salih
Vehid
V
Knowles
Jonathan C
JC
D001673:Biodegradation, Environmental; D002130:Calcium Phosphates / Q000494:pharmacology* / Q000627:therapeutic use; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002516:Ceramics / Q000737:chemistry / Q000592:standards; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects*; D016062:Porosity; D012995:Solubility; D013499:Surface Properties; D015040:Zirconium
D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D015040:Zirconium; C028541:zirconium oxide