Journal of Ultrafine Grained and Nanostructured Materials

Journal of Ultrafine Grained and Nanostructured Materials

Synthesis and Characterization of Nano-Hydroxyapatite/mPEG-b-PCL Composite Coating on Nitinol Alloy

Document Type : Research Paper

Authors
Mohamadreza Etminanfar 1
Jafar Khalil-Allafi 1
Kiyumars Jalili 2
1 Research Center for Advanced Materials, Faculty of Materials Engineering, Sahand University of Technology, Tabriz, Iran
2 Institute of Polymeric Materials, Faculty of Polymer Engineering, Sahand University of Technology, Tabriz, Iran.
10.22059/JUFGNSM.2017.02.03
Abstract
In this study the bioactivity of hydroxyapatite/poly(ε-caprolactone)–poly(ethylene glycol) bilayer coatings on Nitinol superelastic alloy was investigated. The surface of Nitinol alloy was activated by a thermo-chemical treatment and hydroxyapatite coating was electrodeposited on the alloy, followed by applying the polymer coating. The surface morphology of coatings was studied using FE-SEM and SEM. The data revealed that the hydroxyapatite coating is composed of one-dimensional nano sized flakes and the polymer coating is uniformly covered the sublayer. Also, High resolution TEM studies on the hydroxyapatite samples revealed that each flake contains nano-crystalline grains with a diameter of about 15 nm. The hydroxyapatite monolayer coating was rapidly covered by calcium phosphate crystals (Ca/P=1.7) after immersion in simulated body fluid confirming the bioactivity of the nanostructured flakes. However, the flakes were weak against applied external forces because of their ultra-fine thickness. Scratch test was applied on hydroxyapatite/polymer coating to evaluate delamination of the coating from substrate. It was shown that, the polymer coating has a great influence on toughening the hydroxyapatite coating. To assess the degradation effect of the polymer layer on hydroxyapatite coating, samples were immersed in phosphate-buffered saline at 37 ᵒC. SEM studies on the samples revealed that the beneath layer of hydroxyapatite appears after 72 h without any visible change in morphology. It seems that, application of a biodegradable polymer film on the nanostructured hydroxyapatite coating is a good way to support the coating during implantation processes
Keywords
Nitinol
HA film
Nano-sized
mPEG-b-PCL
biodegradable
1. Pelton AR, Stöckel D, Duerig TW. Medical Uses of Nitinol. Materials Science Forum. 2000;327-328:63-70.
2. Elahinia MH, Hashemi M, Tabesh M, Bhaduri SB. Manufacturing and processing of NiTi implants: A review. Progress in Materials Science. 2012;57(5):911-46.
3. Tian H, Schryvers D, Liu D, Jiang Q, Van Humbeeck J. Stability of Ni in nitinol oxide surfaces. Acta Biomaterialia. 2011;7(2):892-9.
4. Espinar E, Llamas JM, Michiardi A, Ginebra MP, Gil FJ. Reduction of Ni release and improvement of the friction behaviour of NiTi orthodontic archwires by oxidation treatments. Journal of Materials Science: Materials in Medicine. 2011;22(5):1119-25.
5. Cui ZD, Chen MF, Zhang LY, Hu RX, Zhu SL, Yang XJ. Improving the biocompatibility of NiTi alloy by chemical treatments: An in vitro evaluation in 3T3 human fibroblast cell. Materials Science and Engineering: C. 2008;28(7):1117-22.
6. Campbell AA. Bioceramics for implant coatings. Materials Today. 2003;6(11):26-30.
7. Watabe N. Studies in shell formation. Crystal–matrix relation-ships in the inner layers of mollusk shells. Calcif Tissue Int. 1965;29:163–7..
8. Du C, Cui FZ, Feng QL, Zhu XD, de Groot K. Tissue response to nano-hydroxyapatite/collagen composite implants in marrow cavity. Journal of Biomedical Materials Research. 1998;42(4):540-8.
9. Kim H-W, Knowles JC, Kim H-E. Hydroxyapatite and gelatin composite foams processed via novel freeze-drying and crosslinking for use as temporary hard tissue scaffolds. Journal of Biomedical Materials Research Part A. 2004;72A(2):136-45.
10. Fratzl P, Gupta HS, Paschalis EP, Roschger P. Structure and mechanical quality of the collagen–mineral nano-composite in bone. J Mater Chem. 2004;14(14):2115-23.
11. Peter M, Ganesh N, Selvamurugan N, Nair SV, Furuike T, Tamura H, et al. Preparation and characterization of chitosan–gelatin/nanohydroxyapatite composite scaffolds for tissue engineering applications. Carbohydrate Polymers. 2010;80(3):687-94.
12. Kim H-W, Knowles JC, Kim H-E. Hydroxyapatite/poly(ε-caprolactone) composite coatings on hydroxyapatite porous bone scaffold for drug delivery. Biomaterials. 2004;25(7-8):1279-87.
13. Coombes AGA, Rizzi SC, Williamson M, Barralet JE, Downes S, Wallace WA. Precipitation casting of polycaprolactone for applications in tissue engineering and drug delivery. Biomaterials. 2004;25(2):315-25.
14. Oyane A, Kim H-M, Furuya T, Kokubo T, Miyazaki T, Nakamura T. Preparation and assessment of revised simulated body fluids. Journal of Biomedical Materials Research. 2003;65A(2):188-95.
15. Etminanfar MR, Khalil-Allafi J, Parsa AB. On the electrocrystallization of pure hydroxyapatite nanowalls on Nitinol alloy using a bipolar pulsed current. Journal of Alloys and Compounds. 2016;678:549-55.
16. Ikoma T, Yamazaki A, Nakamura S, Akao M. Preparation and Structure Refinement of Monoclinic Hydroxyapatite. Journal of Solid State Chemistry. 1999;144(2):272-6.
17. Elliott JC. Preface. Structure and Chemistry of the Apatites and Other Calcium Orthophosphates: Elsevier; 1994. p. v-vii.
18. Haverty D, Tofail SAM, Stanton KT, McMonagle JB. Structure and stability of hydroxyapatite: Density functional calculation and Rietveld analysis. Physical Review B. 2005;71(9).
19. Ikoma T, Yamazaki A, Nakamura S, Akao M. Preparation and Structure Refinement of Monoclinic Hydroxyapatite. Journal of Solid State Chemistry. 1999;144(2):272-6.
20. Hochrein O, Kniep R, Zahn D. Atomistic Simulation Study of the Order/Disorder (Monoclinic to Hexagonal) Phase Transition of Hydroxyapatite. Chemistry of Materials. 2005;17(8):1978-81.
21. Landolt D, Marlot A. Microstructure and composition of pulse-plated metals and alloys. Surface and Coatings Technology. 2003;169-170:8-13.
22. Zhu SL, Yang XJ, Cui ZD. Formation of Ca–P layer on the Ti-based bulk glassy alloy by chemical treatment. Journal of Alloys and Compounds. 2010;504:S168-S71.
23. Li S, Garreau H, Vert M. Structure-property relationships in the case of the degradation of massive poly(?-hydroxy acids) in aqueous media. Journal of Materials Science: Materials in Medicine. 1990;1(4):198-206.
24. Huang M-H, Li S, Hutmacher DW, Schantz J-T, Vacanti CA, Braud C, et al. Degradation and cell culture studies on block copolymers prepared by ring opening polymerization of ?-caprolactone in the presence of poly(ethylene glycol). Journal of Biomedical Materials Research. 2004;69A(3):417-27.
 
Journal of Ultrafine Grained and Nanostructured Materials
Volume 50, Issue 2
December 2017
Pages 98-104

  • Receive Date 19 September 2017
  • Revise Date 04 November 2017
  • Accept Date 05 November 2017