Biodegradable Zn-3Cu and Zn-3Cu-0.2Ti alloys with ultrahigh ductility and antibacterial ability for orthopedic applications

doi:10.1016/j.jmst.2020.06.052

Abstract

Abstract:

Zinc (Zn) and its alloys have been proposed as biodegradable implant materials due to their unique combination of biodegradability, biocompatibility, and biofunctionality. However, the insufficient mechanical properties of pure Zn greatly limit its clinical application. Here, we report on the microstructure, mechanical properties, friction and wear behavior, corrosion and degradation properties, hemocompatibility, and cytocompatibility of Zn-3Cu and Zn-3Cu-0.2Ti alloys under three different conditions of as-cast (AC), hot-rolling (HR), and hot-rolling plus cold-rolling (HR + CR). The HR + CR Zn-3Cu-0.2Ti exhibited the best set of comprehensive properties among all the alloy samples, with yield strength of 211.0 MPa, ultimate strength of 271.1 MPa, and elongation of 72.1 %. Immersion tests of the Zn-3Cu and Zn-3Cu-0.2Ti alloys in Hanks’ solution for 3 months indicated that the AC samples showed the lowest degradation rate, followed by the HR samples, and then the HR + CR samples, while the HR + CR Zn-3Cu exhibited the highest degradation rate of 23.9 μm/a. Friction and wear testing of the Zn-3Cu and Zn-3Cu-0.2Ti alloys in Hanks’ solution indicated that the AC samples showed the highest wear resistance, followed by the HR samples, and then the HR + CR samples, while the AC Zn-3Cu-0.2Ti showed the highest wear resistance. The diluted extracts of HR + CR Zn-3Cu and Zn-3Cu-0.2Ti at a concentration of ≤25 % exhibited non-cytotoxicity. Furthermore, both the HR + CR Zn-3Cu and Zn-3Cu-0.2Ti exhibited effective antibacterial properties against S. aureus.

Key words: Cytotoxicity, Degradation behavior, Mechanical properties, Zn-Cu biodegradable metals

Jixing Lin, Xian Tong, Kun Wang, Zimu Shi, Yuncang Li, Matthew Dargusch, Cuie Wen. Biodegradable Zn-3Cu and Zn-3Cu-0.2Ti alloys with ultrahigh ductility and antibacterial ability for orthopedic applications[J]. J. Mater. Sci. Technol., 2021, 68: 76-90.

Figures/Tables 14

References 103

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Samples	Cu	Ti	Impurities	Zn
Zn-3Cu	3.08 ± 0.21	-	0.055 ± 0.012	Bal.
Zn-3Cu-0.2Ti	3.13 ± 0.17	0.225 ± 0.062	0.063 ± 0.015	Bal.

Samples	Cu	Ti	Impurities	Zn
Zn-3Cu	3.08 ± 0.21	-	0.055 ± 0.012	Bal.
Zn-3Cu-0.2Ti	3.13 ± 0.17	0.225 ± 0.062	0.063 ± 0.015	Bal.

Samples	Corrosion potential, E_corr (V vs. SCE)	Corrosion current density, I_corr (μA/cm²)	Corrosion rate, V_corr (μm/a)
AC Zn-3Cu	-0.932 ± 0.157	14.3 ± 0.6	190 ± 8
HR Zn-3Cu	-0.946 ± 0.119	19.2 ± 0.4	255 ± 5
HR + CR Zn-3Cu	-0.979 ± 0.185	23.4 ± 0.7	311 ± 9
AC Zn-3Cu-0.2Ti	-0.961 ± 0.204	10.9 ± 0.4	145 ± 5
HR Zn-3Cu-0.2Ti	-0.982 ± 0.189	19.0 ± 0.5	252 ± 7
HR + CR Zn-3Cu-0.2Ti	-0.993 ± 0.172	22.5 ± 0.8	299 ± 11

Samples	Corrosion potential, E_corr (V vs. SCE)	Corrosion current density, I_corr (μA/cm²)	Corrosion rate, V_corr (μm/a)
AC Zn-3Cu	-0.932 ± 0.157	14.3 ± 0.6	190 ± 8
HR Zn-3Cu	-0.946 ± 0.119	19.2 ± 0.4	255 ± 5
HR + CR Zn-3Cu	-0.979 ± 0.185	23.4 ± 0.7	311 ± 9
AC Zn-3Cu-0.2Ti	-0.961 ± 0.204	10.9 ± 0.4	145 ± 5
HR Zn-3Cu-0.2Ti	-0.982 ± 0.189	19.0 ± 0.5	252 ± 7
HR + CR Zn-3Cu-0.2Ti	-0.993 ± 0.172	22.5 ± 0.8	299 ± 11

Composition	Fabrication method	Yield strength, σ_ys (MPa)	Ultimate tensile strength, σ_uts (MPa)	Elongation, ε (%)	Hardness (HV)	Corrosion rate (μm/a)		Ref.
Composition	Fabrication method	Yield strength, σ_ys (MPa)	Ultimate tensile strength, σ_uts (MPa)	Elongation, ε (%)	Hardness (HV)	Electro- chemical	immersion	Ref.
						-	33 ± 1 (c-SBF, 20d)	[31]
Zn-2Cu	AE	200 ± 4	240 ± 1	46.8 ± 1.4	-	-	27 ± 5 (c-SBF, 20d)	[31]
Zn-3Cu	AE	214 ± 1	257 ± 1	47.2 ± 1.0	-	5 (Hanks’)	30 ± 4 (c-SBF, 20d)	[31,65]
Zn-4Cu	AE	227 ± 5	271 ± 1	50.6 ± 2.8	-	-	25 ± 5 (c-SBF, 20d)	[31]
Zn-3Cu-0.1Mg	AE	345 ± 22	366 ± 17	5.3 ± 1.3	-	18 (Hanks’)	23 ± 2 (Hanks’, 20d)	[65]*
Zn-3Cu-0.5Mg	AE	404 ± 10	416 ± 6	2.1 ± 0.9	-	24 (Hanks’)	30 ± 3 (Hanks’, 20d)	[65]*
Zn-3Cu-1Mg	AE	427 ± 7	440 ± 10	0.9 ± 0.4	-	180 (Hanks’)	43 ± 4 (Hanks’, 20d)	[65]
Zn-3Cu-0.5Fe	AE	232 ± 3	284 ± 2	32.7 ± 4.2	76.1 ± 1.3	104 (SBF)	64 ± 4 (SBF, 20d)	[66]
Zn-3Cu-1Fe	AE	222 ± 6	272 ± 8	19.6 ± 1.4	82.2 ± 1.0	130 (SBF)	69 ± 7 (SBF, 20d)	[66]
Zn-1Cu-0.1Ti	CR + CD	177	200	21	-	-	20 (HBSS, 30d)	[67]
Zn-1Cu-0.2Mn - 0.1Ti	CR + CD	196	212	19	-	-	20 (HBSS, 30d)	[67]
Zn-2Cu	AC	96 ± 3	128 ± 7	2.1 ± 0.2	-	-	11 ± 4 (Hanks’, 30d)	[61]*
Zn-2Cu-0.05Ti	AC	132 ± 6	177 ± 8	2.5 ± 0.2	-	-	22 ± 7 (Hanks’, 30d)	[61]*
Zn-2Cu-0.1Ti	AC	113 ± 3	146 ± 7	1.8 ± 0.2	-	-	28 ± 9 (Hanks’, 30d)	[61]*
Zn-1Cu-0.1Ti	AC HR HR + CR	86 ± 3 175 ± 4 204 ± 4	92 ± 4 206 ± 6 250 ± 4	1.4 ± 0.8 39.2 ± 1.4 75.2 ± 1.9	72.6 ± 0.6 70.6 ± 1.8 56.4 ± 0.8	315 ± 6 1628 ± 13 991 ± 7 (Hanks’)	29 ± 22 34 ± 18 32 ± 11 (Hanks’, 30d)	[41]
Zn-3Cu	AC HR HR + CR	95 ± 2 189 ± 4 193 ± 3	98 ± 3 244 ± 4 268 ± 3	1.2 ± 0.3 38.4 ± 0.8 66.4 ± 0.9	79.8 ± 2.0 79.0 ± 1.3 62.0 ± 1.4	190 ± 8 255 ± 5 311 ± 9 (Hanks’)	19 ± 2 21 ± 3 24 ± 2 (Hanks’, 90d)	this study
Zn-3Cu-0.2Ti	AC HR HR + CR	117 ± 3 224 ± 3 211 ± 3	124 ± 3 290 ± 4 271 ± 5	1.2 ± 0.3 42.7 ± 1.1 72.1 ± 1.6	83.8 ± 1.8 80.6 ± 1.5 63.6 ± 1.0	145 ± 5 252 ± 7 299 ± 11 (Hanks’)	18 ± 3 21 ± 2 22 ± 2 (Hanks’, 90d)	this study