Ca-P-O thin film preparation, modification and characterisation

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dc.contributor.author Arcot Rajashekar, Ananda Sagari
dc.date.accessioned 2012-01-12T09:54:52Z
dc.date.available 2012-01-12T09:54:52Z
dc.date.issued 2011
dc.identifier.isbn 978-951-39-4586-2
dc.identifier.uri http://urn.fi/URN:ISBN:978-951-39-4586-2 en
dc.identifier.uri http://hdl.handle.net/123456789/37195
dc.description.abstract Bioceramics are biocompatible ceramic materials, that interact with biological systems of the body to treat, strengthen or replace body functions. Most conventional bioceramics are oxide ceramics, glass ceramics and calcium phosphate ceramics. Among these calcium phosphates, synthetic hydroxyapatite has been extensively studied due to its biomimetic properties similar to that of natural bone. One approach to prepare synthetic hydroxyapatite is to first deposit amorphous Ca-P-O thin film and then by means of post deposition annealing initiate the formation of hydroxyapatite crystals to the film. In addition to the correct film composition and crystalline structure, other surface properties such as wettability and surface nano- and microtopography are very significant for the biocompatibility. In this study Ca-P-O thin films were deposited using two different techniques, ion beam sputtering and atomic layer deposition (ALD). Films deposited using both techniques were amorphous after deposition. For sputter deposited films, the Ca/P atomic ratio determined by means of ion beam analysis approached stoichiometric hydroxyapatite when hydroxyapatite powder doped with extra phosphorous was used as the sputtering target. Though the sputtered films showed good biocompatibility in cell attachment studies, the dissolution of as-deposited films in cell culture medium is a disadvantage. The surface of as-deposited and annealed thin films deposited using ALD were locally modified by high and low energy irradiation. After low energy ion irradiation the as-deposited films showed an increase in hydrophilicity, which was determined using contact angle measurements, and also greater spreading of mouse pre-osteoblast cells. The effect of surface topography was studied by abrading Ti metal substrates to different roughnesses before depositing 2–50 nm thick ALD Ca-P-O films on them. Ti was selected in order to combine the biocompatibility of Ca-P-O thin-films with the mechanical strength of the Ti metal substrate. Ca-P-O films deposited on smoother substrates showed higher Ca/P atomic ratios than those on the rough substrates, demonstrating the influence of roughness on the film growth during the deposition. As-deposited Ca-P-O films acted as equally good cell culture substrate as untreated Ti samples used as a control. After post deposition annealing at 800 C, Ca-P-O films were crystallized on Si substrates and showed filopodic morphology of pre-osteoblast cells. Films on Ti showed also filopodic morphology of cells after 700 C annealing but at 800 C the number of cells substantially dropped, most likely due to formation of a less biocompatible TiO2 rutile phase on the surface. fi
dc.format.extent Verkkokirja (53 s.).
dc.language.iso eng
dc.publisher University of Jyväskylä
dc.relation.ispartofseries Research report / Department of Physics, University of Jyväskylä;0075-465X ;no. 12/2011
dc.relation.isversionof ISBN 978-951-39-4585-5
dc.subject.other biokeraamit
dc.subject.other atomikasvatusmenetelmät
dc.subject.other bioceramics
dc.subject.other titanium
dc.subject.other silicon
dc.subject.other prosthesis
dc.title Ca-P-O thin film preparation, modification and characterisation
dc.type Diss. fi
dc.identifier.urn URN:ISBN:978-951-39-4586-2
dc.subject.ysa biofysiikka
dc.subject.ysa lääketieteellinen fysiikka
dc.subject.ysa ohutkalvot
dc.subject.ysa pinnoitteet
dc.subject.ysa keraamiset materiaalit
dc.subject.ysa implantit
dc.subject.ysa tekonivelet
dc.subject.ysa silikoni
dc.subject.ysa titaani
dc.subject.ysa kevytmetallit
dc.subject.kota 114
dc.type.dcmitype Text en
dc.type.ontasot Väitöskirja fi
dc.type.ontasot Doctoral dissertation en
dc.contributor.tiedekunta Matemaattis-luonnontieteellinen tiedekunta fi
dc.contributor.tiedekunta Faculty of Mathematics and Science en
dc.contributor.yliopisto University of Jyväskylä en
dc.contributor.yliopisto Jyväskylän yliopisto fi

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