title: A study of strontium doped calcium phosphate coatings on AZ31.
abstract: Calcium phosphate (CaP) coatings have been studied to tailor the uncontrolled non-uniform corrosion of Mg based alloys while simultaneously enhancing bioactivity. The use of immersion techniques to deposit CaP coatings is attractive due to the ability of the approach to coat complex structures. In the current study, AZ31 substrates were subjected to various pretreatment conditions prior to depositing Sr(2+) doped and undoped CaP coatings. It was hypothesized that the bioactivity and corrosion protection of CaP coatings could be improved by doping with Sr(2+). Heat treatment to elevated temperatures resulted in the diffusion of alloying elements, Mg and Zn, into the pretreated layer. Sr(2+) doped and undoped CaP coatings formed on the pretreated substrates consisted of biphasic mixtures of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA). Electrochemical corrosion experiments indicated that the extent of Sr(2+) doping and pretreatment both influenced the corrosion protection. Cytotoxicity was evaluated with MC3T3-E1 mouse preosteoblasts and human mesenchymal stem cells (hMSCs). For both cell types, proliferation decreased upon increasing the Sr(2+) concentration. However, both osteogenic gene and protein expression significantly increased upon increasing Sr(2+) concentration. These results suggest that Sr(2+) doped coatings are capable of promoting osteogenic differentiation on degradable Mg alloys, while also enhancing corrosion protection, in comparison to undoped CaP coatings.
authors.affiliation: Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA. Electronic address: sss42@pitt.edu.
authors.forename: Satish S
authors.initials: SS
authors.lastname: Singh
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA. Electronic address: abr20@pitt.edu.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Roy
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Boeun E
authors.initials: BE
authors.lastname: Lee
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: John
authors.initials: J
authors.lastname: Ohodnicki
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Autrine
authors.initials: A
authors.lastname: Loghmanian
authors.affiliation: Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Ipsita
authors.initials: I
authors.lastname: Banerjee
authors.affiliation: Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261, USA. Electronic address: pkumta@pitt.edu.
authors.forename: Prashant N
authors.initials: PN
authors.lastname: Kumta
mesh_terms: D000497:Alloys / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology; D003343:Corrosion; D017886:Durapatite / Q000737:chemistry; D055664:Electrochemical Techniques; D006801:Humans; D008274:Magnesium / Q000737:chemistry; D059630:Mesenchymal Stem Cells; D051379:Mice; D010012:Osteogenesis / Q000187:drug effects; D013324:Strontium / Q000737:chemistry*
chemical_list: D000497:Alloys; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C586533:Mg-Al-Zn-Mn-Si-Cu alloy; D017886:Durapatite; C020243:calcium phosphate; D008274:Magnesium; D013324:Strontium
keywords: Calcium phosphate; Magnesium alloy; Osteogenic differentiation; Strontium