Influence of altered Ca-P based electrolytes on the anodised titanium bioactivity
Anodic oxidation (AO) of titanium is a common electrochemical process for surface modification of metallic surfaces and is conducted in an electrolyte solution. Anodisation of titanium implants can generate a coating with optimal characteristics to accelerate the growth of bone-like apatite. The p...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2021
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/1920/ http://eprints.uthm.edu.my/1920/1/J12269_5f9f5ab97dfe23d7645b6cb568947dbd.pdf |
| Summary: | Anodic oxidation (AO) of titanium is a common electrochemical process for surface modification of metallic
surfaces and is conducted in an electrolyte solution. Anodisation of titanium implants can generate a coating with
optimal characteristics to accelerate the growth of bone-like apatite. The present work aims to develop a novel
AO electrolyte formulation of a Ca–P base solution containing three different alteration agents. The characteristics
of the anodised coating were modified by varying the volume fractions of the alteration agents, namely
sulphuric acid, hydrogen peroxide, and acetic acid in a base solution of β-glycerolphosphate disodium salt
pentahydrate (β-GP) and calcium acetate monohydrate (CA). The surface morphology, mineralogy, wettability,
and bioactivity of these coatings were analysed using scanning electron microscopy (SEM), X-ray diffraction
(XRD), contact angle analysis, and in vitro testing using simulated body fluid (SBF). Anodisation in a mixture of
β-GP + CA electrolyte resulted in the formation of Ca-P-rich oxide coating (with surface features with a donutlike
shape) and when altered with 12.5 vol% sulphuric acid, highly defined spiky needle-like morphology was
seen on the surface. These coatings were composed of hydroxyapatite, tricalcium phosphate, and calcium
diphosphate. After 7 days of SBF immersion, the surface was observed to contain a dense layer of bone-like
apatite. However, alteration using acetic acid did not result in any significant changes to the surface characteristics
and no bone-like apatite formation was observed even after soaking in SBF for 7 days. Alteration using
hydrogen peroxide resulted in an anodised coating that assisted the growth of bone-like apatite layer on the
coating surfaces after soaking in SBF for 7 days. The differences in coating performance are linked to the presence
of different functional ions with hydronium groups (from sulphuric acid) being superior compared to the
carboxyl ions (from acetic acid). The coating produced by sulphuric acid alteration demonstrated super hydrophilicity
and roughe |
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