Bioactivity of strontium-monetite coatings for biomedical applications

The bioactivity of calcium phosphate (CaP) coatings can be controlled by different CaP phase precipitation and/or addition of foreign ions to their crystal lattice. Cationic substitution of strontium (Sr) into CaP coatings has gained a great attention due to the unique potential of Sr ions on stimulating new bone formation while inhibiting bone resorption. In this study, a novel route was used for producing Sr-substituted calcium phosphate coating on metallic substrates, containing 5 mol%, 10 mol% and 15 mol% Sr concentration, by chemical deposition method. The obtained Sr-substituted calcium phosphate coatings were structurally characterized by Xray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses. The presence of strontium ions into calcium phosphate phase fostered monetite precipitation, instead of brushite, and this cationic substitution was investigated by Rietveld refinement method. FEG-SEM analysis showed the bioactivity behavior by the precipitation of characteristic bone-like apatite on the 5% Sr-monetite and HA coatings after 14 days of incubation, using McCoy culture medium. The biological performance of the coated surfaces showed that hDPSCs viability was enhanced in the presence of Sr2+ ion concentration up to 10 mol% (p < 0.05) when compared to the uncoated titanium substrates and hydroxyapatite coatings. The results suggested the 5% Sr-monetite as a potential alternative for hydroxyapatite coatings, because of the improved biological responses in this study45675687579CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJ140144/2012-910.980/13-02015005263The authors would like to acknowledge Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) (2015005263, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (140144/2012-9) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (10.980/13-0) for the grants, and the institutions IME, NYUCD and CBPF for their cooperation and support for the paper. We are grateful to Dr. Isac de Castro (Division of Molecular Medicine, Department of Medicine, Clinical Hospital, University of São Paulo, Brazil) for excellent statistical assistance. The authors declare no conflicts of interest related to this study