Preparation of bioactive surface via gel oxidation on titanium for biomedical application (hip joint replacement)
Titanium and its alloys are widely used as implant in biomedical applications. They have good mechanical and chemical properties, biocompatibility and biointegration with human body, but they have no ability to bond directly to natural bone. Therefore, alkali and heat treatments (gel oxidation) w...
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Format: | Thesis |
Language: | English English English |
Published: |
2018
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Subjects: | |
Online Access: | http://eprints.uthm.edu.my/265/1/24p%20TAN%20KWOK%20JOON.pdf http://eprints.uthm.edu.my/265/2/TAN%20KWOK%20JOON%20WATERMARK.pdf http://eprints.uthm.edu.my/265/3/TAN%20KWOK%20JOON%20COPYRIGHT%20DECLARATION.pdf |
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Summary: | Titanium and its alloys are widely used as implant in biomedical applications. They
have good mechanical and chemical properties, biocompatibility and biointegration
with human body, but they have no ability to bond directly to natural bone. Therefore,
alkali and heat treatments (gel oxidation) were introduced to improve the bioactivity
of titanium by forming a mixture of sodium titanate and rutile on the surface of
titanium. This method enables titanium to possess a bioactive surface which is
essential to induce the apatite formation. This study aims to investigate the effects of
alkali, sodium removal and heat treatments on in vitro bioactivity of titanium. UV light
irradiation was used to study the effect on in vitro bioactivity of titanium. Alkalitreated
titanium subjected to heat treatment in air have shown better overall in vitro
performance than those treated in argon atmosphere. Therefore, the sodium removal
treatment (dilute hydrochloric acid (HCl) treatment) was introduced to convert sodium
titanate into anatase to improve the bioactivity of titanium treated in argon atmosphere.
Thus, four samples (AT-0.5-HT500R, AT-0.5-HT600R, AT-5-HT500R and AT-5-
HT600R) with different ratios of anatase to rutile were produced by varying the
concentration of HCl acid treatment and heating temperature in argon atmosphere. It
was found that the incorporation of sodium removal treatment has reduced two times
the duration of apatite formation as compared with the conventional alkali and heat
treatments. In order to further enhance the bioactivity, these samples were subjected
to six different conditions of ultraviolet light irradiation and followed by in vitro
bioactivity test. As a result, AT-5-HT500R (82.2% anatase and 17.8% rutile) was
proven to deliver the best performance. It was confirmed that UV light irradiation
enhances the bioactivity by removing hydrocarbon, inducing superhydrophilicity and
forming OH groups. It was discovered that the duration of apatite formation was
shortened to 7 days. Furthermore, the continuous UVA irradiation during in vitro test
resulted in the acceleration of bonelike apatite formation in 3 days. It can be concluded
that the sodium removal treatment and UV light irradiation give very significant impact to the formation of bonelike apatite on the titanium surfaces for biomedical
applications. |
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