The interaction of plasma proteins with nano-size fluoride-substituted apatite powders

Phase pure (HAp) and fluoride-substituted apatite (FHAp) powders were synthesized by the hydrothermal method and their specific surface area was determined by atomic force microscopy (AFM). Human osteoblast cells were used to evaluate the bioactivity of the samples. The influence of fluoride ions on the alteration of cell medium components was analyzed using UV–visible spectroscopy in different exposure times. The protein interaction behavior with the pure and substituted powders was assessed by the Bradford method and SDS-PAGE analysis. The mRNA expression level was detected by real time PCR and it was observed that the presence of an optimal level of fluoride ions in the apatite structure has an inductive effect on collagen I and alkaline phosphatase (ALP) expression levels. A similar trend was also observed in the protein adsorption profile indicating that the fluoride content in the apatite lattice has a significant impact on controlling its biological performance. The maximum protein adsorption was observed on the sample with the chemical composition of Ca10(PO4)6(OH)1.33F0.67.