In vitro Response of Human Osteoblasts Cultured on Strontium Substituted Hydroxyapatites

Abstract

The goal of this study was to analyze the response of osteoblasts cultured on strontium substituted hydroxyapatites (HAP-Sr) of well-defined high crystallinity deposited as thin films on glass plates. Up to now, this aspect has not been carefully investigated in the context of bio-ceramics. In this study, we present the osteoblasts activity on synthesized HAP-Sr for different amounts of strontium substitution for calcium within the hydroxyapatite (Ca10(PO4)6(OH)2, HAP) lattice, namely HAP-5%Sr, HAP-10%Sr, HAP-15%Sr and HAP-59.2%Sr (Sr-HAP, of formula Sr10(PO4)6(OH)2), in comparison with stoichiometric pure HAP, chosen as control. Each bio-ceramic was deposited as thin multilayers self-assembled substrate (scaffold) and chemically bonded to the surface of glass plates. These coatings revealed by AFM and SEM imaging a granular texture formed from bio-ceramic nanoparticles. They possessed a high degree of crystallinity, i.e. 68% to 86%, depending on the Sr amount within the HAP lattice, as judged by XRD. Osteoblasts were cultured up to 21days and displayed enhanced adhesion and proliferation particularly evidenced on relatively high strontium contents (especially 5 and 10 weight %, determined by SEM-EDX), where the alkaline phosphatase activity and type I collagen were strongly evidenced. These bio-ceramics showed a high in vitro biocompatibility stimulating the activity of osteoblasts in the process of bone formation. These nano biomaterials can have applications in orthopedic and dental surgery improving the osteointegration as coatings of bone implants as well as for bone repair and regeneration.

<p>Advanced Mg, Zn, Sr, Si Multi-Substituted Hydroxyapatites for Bone Regeneration</p>

“…20,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Sr is reported as a vector for bone regeneration. 7 Sr is recognized to adjust bone turnover in favor of bone formation by stimulating osteoblast activity and their proliferation, 23,34 as well as by reducing bone resorption and mediating inhibition of osteoclast activity. 25 It was suggested that Sr concentration is greater in the region of high metabolic turnover and in new bone than in old bone.…”

In-vitro Antibacterial Activity of Novel Nanostructured Composites Based on Forsterite and Silver Nanoparticles

“…AFM images were realized on layers of AgNPs and forsterite powders deposited on glass by adsorption from various dispersions. For AFM investigations, AFM JEOL 4210 equipment was used, operated in tapping mode [16][17][18][19] using standard cantilevers with silicon nitride tips (resonance frequency in the range of 200-300 kHz and spring constant 17.5 N/m). The 2D-and 3D-topographies, and cross section profiles were processed by standard AFM procedures.…”

Novel Porous Forsterite Ceramics Biocompatibility and Bioactivity Evaluation

“…Forsterite ceramic, FC-1200, was subjected to cells viability test to determine its biocompatibility in vitro [5,[34][35][36][37][38][39]. The MTT assay is preferred over the other methods of measuring cells viability as it is a sensitive and reliable indicator of the cellular metabolic activity [35,37,38].…”

“…The MTT assay measures cell viability in terms of enzymatic conversion of the MTT tetrazolium compound to water insoluble formazan crystals by the action of mitochondrial reductases present in viable cells [33][34]. The MTT, 3-(4,5-dimethylthiazol-2-yl) -2,5 diphenyl-2H-tetrazolium bromide, water soluble dye readily penetrates viable HFL cells.…”