Osteogenesis-inducing calcium phosphate nanoparticle precursors applied to titanium surfaces

This study investigated the effects of the morphology and physicochemical properties of calcium phosphate (CaP) nanoparticles on osteogenesis. Two types of CaP nanoparticles were compared, namely amorphous calcium phosphate (ACP) nano-spheres (diameter: 9-13 nm) and poorly crystalline apatite (PCA) nano-needles (30-50 nm x 2-4 nm) that closely resemble bone apatite. CaP particles were spin-coated onto titanium discs and implants; they were evaluated in cultured mouse calvarial osteoblasts, as well as after implantation in rabbit femurs. A significant dependence of CaP coatings was observed in osteoblast-related gene expression (Runx2, Col1a1 and Spp1). Specifically, the PCA group presented an up-regulation of the osteospecific genes, while the ACP group suppressed the Runx2 and Col1a1 expression when compared to blank titanium substrates. Both the ACP and PCA groups presented a more than three-fold increase of calcium deposition, as suggested by Alizarin red staining. The removal torque results implied a slight tendency in favour of the PCA group. Different forms of CaP nanostructures presented different biologic differences; the obtained information can be used to optimize surface coatings on biomaterials. © 2013 IOP Publishing Ltd.

Keywords

Amorphous calcium phosphate, Calcium deposition, Calcium phosphate nanoparticles, Physicochemical property, Surface coatings, Titanium discs, Titanium substrates, Titanium surfaces, Biological materials, Biomaterials, Calcium phosphate, Coatings, Gene expression, Gene expression regulation, Nanoparticles, Osteoblasts, Titanium, alizarin red s, apatite, calcium, calcium phosphate, collagen type 1, collagen type 1A1, messenger RNA, nanocoating, nanomaterial, nanoparticle, osteopontin, poorly crystalline apatite, titanium, transcription factor RUNX2, unclassified drug, animal cell, animal tissue, bone development, calvaria, controlled study, femur, gene expression, gene repression, implant, implantation, mouse, newborn, nonhuman, osteoblast, particle size, physical parameters, upregulation