Plasma spray of biofunctional (Mg, Sr)-substituted hydroxyapatite coatings for titanium alloy implants

doi:10.1016/j.jmst.2018.10.020

Abstract

Abstract:

Plasma-sprayed hydroxyapatite (HA) coatings have been widely utilized in load-bearing titanium alloy implants. In this study, Mg, Sr co-substituted HA ((Mg, Sr)-HA) nano-scale powders have been synthesized, which are further used to prepare (Mg, Sr)-HA coatings on Ti-6Al-4V alloys in order to improve the biological functions. The average size of (Mg, Sr)-HA nano particles is 75nm. The average bonding strength for (Mg, Sr)-HA coating and samples after heat treatment at 500 °C or 600 °C for 3 h are 26.17 ± 2.11 MPa, 36.07 ± 4.48 MPa and 37.07±2.95 MPa, respectively. There is a significantly increase of bonding strength likely due to low residual stress after heated treatment. MC3T3-E1 cells show a high proliferation rate when cultured with (Mg, Sr)-HA coating extract compared to the normal culture medium, which also exhibit large extension and deposition of extracellular matrices when adhered on the coating surfaces. Thus, these (Mg, Sr)-HA coatings show high bonding strength and improved biological functions, which offer promising future applications in the fields of orthopedics and dentistry.

Key words: Plasma spray, Hydroxyapatite, Titanium alloys, Biological functions, Bonding strength

Lei Cao, Ihsan Ullah, Na Li, Shiyu Niu, Rujie Sun, Dandan Xia, Rui Yang, Xing Zhang. Plasma spray of biofunctional (Mg, Sr)-substituted hydroxyapatite coatings for titanium alloy implants[J]. J. Mater. Sci. Technol., 2019, 35(5): 719-726.

Figures/Tables 9

Table 1 Plasma-spray parameters employed for preparing HA coating.

Parameters	Values	Units
Current	400	A
Voltage	90	V
Ar gas	0.5	MPa
N gas	0.5	MPa
Pressure of chamber	0.025	mbar

Fig. 1 Characterization of (Mg, Sr)-HA powders: (a) bright field image by TEM, (b) the particle size distribution for (Mg, Sr)-HA powders based on DLS measurement, (c) XRD pattern, and (d) FTIR spectrum for (Mg, Sr)-HA powders.

Fig. 2 Surface morphology of a Ti-6Al-4V sample (a), (Mg, Sr)-HA coating as sprayed (b), and (Mg, Sr)-HA coatings annealed at 500?°C (c) and 600?°C (d) for 3?h. The units of the coordinate axes are micrometers.

Fig. 3 Surface morphology (a) and chemical compositions (b, from the red spot in a) of a (Mg, Sr)-HA coating, and (c) morphology of the cross-section and (d-h) EDS mapping for different elements. The green dashed box in (a) shows the micro pores on the surface of (Mg, Sr)-HA coating, and the yellow dashed box indicates the micro-cracks.

Fig. 4 XRD patterns (a) of (Mg, Sr)-HA coatings and samples annealed at 500?°C or 600?°C for 3?h, and the fitting curves (b)-(d) for the amorphous phase proportion. The green dash line in (a) indicates the shift of HA diffraction peak (211) after heat treatment.

Fig. 5 Bonding strength test for (Mg, Sr)-HA coating samples: (a) a non-cohesive Ti-6Al-4V sample, (b) (Mg, Sr)-HA coating as-sprayed, (c) and (d) fracture morphology of the (Mg, Sr)-HA coating after heat treatment at 600?°C for 3?h, (e) bonding strength test sample and (f) schematic mechanism for (Mg, Sr)-HA coating failure, (g) bonding strength for the HA coating and, (Mg, Sr)-HA coating samples as-sprayed and after heat treatment at 500?°C and 600?°C for 3?h (n?=?3). *p?≤?0.05.

Fig. 6 Proliferation of MC3T3-E1 cells in the presence of (Mg, Sr)-HA extraction after 1, 3, and 5 days of culture. Data represent means?±?S.D. (n?=?3). *p?≤?0.001.

Fig. 7 Immunofluorescence staining of MC3T3-E1 cells cultured with (a, b) normal culture medium and (c, d) (Mg, Sr)-HA coating extract for 48?h. (b, d) show the partially enlarged images from the white dash boxes from (a, c). The cell nuclei and smooth muscle alpha-actin are stained with DAPI (blue) and FITC-phalloidin (green), respectively.

Fig. 8 SEM micrographs of (a) the surface of the control group without cells, and (b-d) cell morphology after culture on the (Mg, Sr)-HA coatings for 5 days. White arrows show filopodia of cells and cellular extensions. A large magnification (d) of the white dash box in (c) shows the cellular extensions.

References

[1]	M.S. Lavine, Science 359 (2018) 173-174.
[2]	T. Takizawa, N. Nakayama, H. Haniu, K. Aoki, M. Okamoto, H. Nomura, M.Tanaka, A. Sobajima, K. Yoshida, T. Kamanaka, Adv. Mater. 30(2018)1703608.
[3]	F. Li, J. Li, H. Kou, L. Zhou, J. Mater.Sci.Technol. 32(2016) 937-943.
[4]	Q. Wang, H. Hu, Y. Qiao, Z. Zhang, J. Mater.Sci.Technol. 28(2012) 109-117.
[5]	P. Xiu, Z. Jia, J. Lv, C. Yin, Y. Cheng, K. Zhang, C. Song, H. Leng, Y. Zheng, H. Cai,ACS Appl. Mater. Interfaces 8 (2016) 17964-17975.
[6]	Z. Jia, X. Peng, X. Pan, W. Zhou, Y. Cheng, S. Wei, Y. Zheng, T. Xi, H. Cai, Z. Liu,ACS Appl. Mater. Interfaces 8 (2016) 28495-28510.
[7]	N. Hijon, M. Manzano, A.J. Salinas, M. Vallet-Regi, Chem. Mater. 17(2005)1591-1596.
[8]	K. Li, C. Wang, J. Yan, Q. Zhang, B. Dang, Z. Wang, Y. Yao, K. Lin, Z. Guo, L. Bi,Sci. Rep. 8(2018) 1843.
[9]	X. Li, P. Gao, P. Wan, Y. Pei, L. Shi, B. Fan, C. Shen, X. Xiao, K. Yang, Z. Guo, Sci.Rep. 7(2017) 40755.
[10]	P. Liu, E. Domingue, D.C. Ayers, J. Song, ACS Appl. Mater. Interfaces 6 (2014)7141-7152.
[11]	S. Maher, G. Kaur, L. Limamarques, A. Evdokiou, D. Losic, ACS Appl. Mater.Interfaces 9 (2017) 29562-29570.
[12]	Y. Zhang, X. Liu, Z. Li, S. Zhu, X. Yuan, Z. Cui, X. Yang, P. Chu, S. Wu, ACS Appl.Mater. Interfaces 10 (2018) 1266-1277.
[13]	H.P. Felgueiras, S.D. Sommerfeld, N.S. Murthy, J. Kohn, V. Migonney, Langmuir30(2014) 9477-9483.
[14]	J.M. Gomez-Vega, E. Saiz, A.P. Tomsia, T. Oku, K. Suganuma, G.W. Marshall, S.J. Marshall, Adv. Mater. 12(2010) 894-898.
[15]	J. Hu, R. Fraser, J.J. Russell, B. Ben-Nissan, J. Mater.Sci.Technol. 16(2000)591-595.
[16]	R.S. Bedi, L.P. Zanello, Y. Yan, Adv. Funct. Mater. 19(2009) 3856-3861.
[17]	J.M. Gomez-Vega, A. Hozumi, H. Sugimura, O. Takai, Adv. Mater. 13(2001)822-825.
[18]	D.J. Haders, A. Burukhin, E. Zlotnikov, R.E. Riman, Chem. Mater. 20(2008)7177-7187.
[19]	C.J. Watson, D. Tinsley, A.R. Ogden, J.L. Russell, S. Mulay, E.M. Davison, Br.Dent. J. 187(1999) 90-94.
[20]	J. Weng, X. Liu, X. Li, X. Zhang, Biomaterials 16 (1995) 39-44.
[21]	Y. Cao, J. Weng, J. Chen, J. Feng, Z. Yang, X. Zhang, Biomaterials 17 (1996)419-424.
[22]	Y. Yang, K.H. Kim, J.L. Ong, Biomaterials 26 (2005) 327-337.
[23]	J.H. Shepherd, D.V. Shepherd, S.M. Best, J. Mater.Sci.Mater. Med. 23(2012)2335-2347.
[24]	G. Graziani, M. Bianchi, E. Sassoni, A. Russo, M. Marcacci, Mater. Sci. Eng. C 74(2016) 219-229.
[25]	W. Mróz, A. Bombalska, S. Burdy′nska, M. Jedy′nski, A. Prokopiuk, B. Budner, A.′Slósarczyk, A. Zima, E. Menaszek, A. ′Scis?owska-Czarnecka, J. Mol.Struct. 977(2010) 145-152.
[26]	R. Mangal, B. Amit, B. Susmita, J. Biomed.Mater.Res. 99B(2011) 258-265.
[27]	T. Huang, Y. Xiao, S. Wang, Y. Huang, X. Liu, F. Wu, Z. Gu, J.Therm.SprayTechnol. 20(2011) 829-836.
[28]	M. Avci, B. Yilmaz, A. Tezcaner, Z. Evis, Ceram. Int. 43(2017) 9431-9436.
[29]	A.R. Boyd, L. Rutledge, L.D. Randolph, I. Mutreja, B.J. Meenan, J. Mater.Sci.Mater. Med. 26(2015) 65-79.
[30]	A.R. Boyd, L. Rutledge, L.D. Randolph, B.J. Meenan, Mater. Sci. Eng. C 46 (2015)290-300.
[31]	B. Liu, X. Zhang, G. Xiao, Y. Lu, Mater. Sci. Eng. C 47 (2015) 97-104.
[32]	S.R. Kim, J.H. Lee, Y.T. Kim, D.H. Riu, S.J. Jung, Y.J. Lee, S.C. Chung, Y.H. Kim,Biomaterials 24 (2003) 1389-1398.
[33]	Z. Geng, Z. Li, Z. Cui, S. Zhu, Y. Liang, W. Lu, X. Yang, J. Mater. Chem. B 3 (2015)3738-3746.
[34]	S.V. Dorozhkin, M. Epple, Angew. Chem. Int. Ed. 41(2002) 3130-3146.
[35]	H.C. Gledhill, I.G. Turner, C. Doyle, Biomaterials 22 (2001) 1233-1240.
[36]	H. Lin, H. Xu, X. Zhang, K. De Groot, J. Biomed.Mater.Res. 43(1998) 113-122.
[37]	C. Combes, C. Rey, Acta Biomater. 6(2010) 3362-3378.
[38]	Y.C. Tsui, C. Doyle, T.W. Clyne, Biomaterials 19 (1998) 2031-2043.