Biocompatibility of Zr-based bulk metallic glasses: effects of composition and roughness

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Biocompatibility of Zr-based bulk metallic
glasses effects of composition and roughness

• Lu Huang a, b, Zheng Cao a, Wei He a, Harry Meyer
  c,
• Peter K. Liaw a, Tao Zhang b

Department of Materials Science and Engineering,
The University of Tennessee, Knoxville, TN
37996-2200, USA School of Materials Science and
Engineering, Beijing University of Aeronautics
and Astronautics, Beijing 100083,
China Microscopy Group, Metals and Ceramics
Division, Oak Ridge National Laboratory, 1 Bethel
Valley Road, Oak Ridge, TN 37831, USA
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Outline

• Motivation
• Critical issues
• Experimental methods
• Results and discussions
• Conclusions

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Motivation
Challenges of Traditional Crystalline Biomedical Alloys Novelties of Bulk Metallic Glasses
Stress shielding Low elastic modulus
Immune rejection High strength to weight ratio
Fatigue fracture High strength and fatigue endurance limit
Wear debris Good wear resistance
Good corrosion resistance
Biomedical Applications of BMGs
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Research Background (Contd)
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Research Background (Contd)
Attractions Compositions
Zr Biocompatible element Zr55Al10Cu30Ni5
Reduced content of Ni Zr55Al10Cu30Ni5
Good glass forming ability Zr55Al10Cu30Ni5
Improved glass forming ability and mechanical properties (Zr55Al10Cu30Ni5)99Y1
Y Not known as a toxic metal (Zr55Al10Cu30Ni5)99Y1
Beneficial effects on corrosion resistance ? (Effect of rare earth elements additions on corrosion resistance of stainless steels to pitting in chloride solutions) (Zr55Al10Cu30Ni5)99Y1
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Critical Issues

• To investigate the corrosion behaviors of
  Zr55Al10Cu30Ni5 and (Zr55Al10Cu30Ni5)99Y1 BMGs in
  a physiologically-relevant environment
• To preliminarily study the cytotoxicity of
  Zr55Al10Cu30Ni5 and (Zr55Al10Cu30Ni5)99Y1 BMGs
• To determine the effects of 1 at. Y addition and
  different roughness on the biocompatibility of
  Zr-based BMGs
• To compare the results of Zr-based BMGs with
  those of standard, crystalline biomaterials

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Experimental Methods

• Samples preparation
• Materials Zr55Al10Cu30Ni5,
• (Zr55Al10Cu30Ni5)99Y1 (at.)
• Control Ti-6Al-4V

Arc-melting copper mold casting
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Experimental Methods (Contd)

• Electrochemical tests Cyclic-anodic-polarization

Three-electrode cell
Working electrode (WE) the corrosion
sample Reference electrode (RE) saturated
calomel electrode (SCE) Counter electrode (CE)
platinum foil
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Experimental Methods (Contd)

• Cytotoxicity tests

Position the sample in the middle of the well
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Experimental Methods (Contd)

• Statistical analysis
• Corrosion data were reported as
• means standard deviation (STDEV) (n 5)
• Cytotoxicity data were reported as
• means standard error of mean (SEM) (n 3)
• Statistical comparisons were performed using
  Students t-test
• A P-value less than 0.05 was considered
  statistically significant

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Results and Discussions
Cyclic-anodic polarization results
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Results and Discussions (Contd)
Corrosion parameters
Faradays Law CPR 0.327 (Micorr)/mr
Pitting overpotential Epit - Ecorr
CPR (mm/y) - corrosion penetration rate, M
(g/mol) - atomic mass, r (g/cm3) density, m -
metal-ion valence, icorr (mA/m2) corrosion
current density.
describes the resistance to the onset of pitting
Ref. Lu Huang, Dongchun Qiao, Brandice Green et
al. Bio-corrosion study on zirconium- based
bulk metallic glasses, Intermetallics, 2009
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Results and Discussions (Contd)
XPS Survey
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Results and Discussions (Contd)
Cell adhesion
Ti-6Al-4V Alloy
(Zr55Al10Cu30Ni5)99Y1 BMG
Zr55Al10Cu30Ni5 BMG
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Results and Discussions (Contd )
Viability / Proliferation
A
A
AB
AB
B
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Conclusions

• Y addition effects
• beneficial to the in-vitro corrosion resistance
• neutral to the cytotoxicity properties
• Surface roughness effects
• Cell adhesion
• No significant difference
• Proliferation
• No significant difference for Ti alloy and
  (Zr55Al10Ni5Cu30 )99Y1 BMG
• Rougher surface is better for Zr55Al10Ni5Cu30
  BMG
• Comparison with standard crystalline biomedical
  alloys
• a comparable corrosion resistance and
  biocompatibility

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Acknowledgement

• This work is financially supported by
• The National Science Foundation (NSF)
  International Materials Institutes (IMI) Program
  (DMR-0231320)
• The National Science Foundation Integrative
  Graduate Education and Research Training (IGERT)
  Program
• The National Science Foundation of China (NSFC)
  (Nos. 50771005 and 50631010)
• The authors are grateful to Dr. Dunlap for his
  kind help

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Thanks!Questions or Comments?
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Results and Discussions
Fundamentals of corrosion
Schematic cyclic-anodic-polarization behaviors of
passive materials