Degradation and Characterization of Resorbable Phosphate-Based Glass Thin-Film Coatings Applied by Radio-Frequency Magnetron Sputtering

Abstract

(2015) Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering. ACS Applied Materials and Interfaces, 7 (49). pp. 27362-27372. ISSN 1944-8252 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/34759/1/Pre-Proof-Degradation%20and%20Characterisation %20of%20Resorbable%20Thin%20Films%20%28002%29.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. respectively. This factor led to highly soluble coatings, exhibiting a t 1/2 degradation dependence in the first 2 hours in distilled water, followed by a more characteristic linear profile as the subsequent layers were less soluble. Hydration and degradation was observed to preferentially occur, forming voids characteristic of pitting corrosion which was confirmed by use of a Focused Ion Beam. Coating degradation in PBS precipitated a (PO3) -metaphosphate, X-Ray amorphous layer, which remained adherent to the substrate and seemingly formed a protective diffusion barrier which inhibited further coating degradation.The implications are that whilst compositionally similar, sputter deposited coatings and melt quenched glasses are structurally dissimilar, most notably, with regards to the surface layer.This factor has been attributed to surface etching of the as deposited coating layer during 2 deposition and variation in the thermal history between the processes of magnetron sputtering and melt quenching.

Bioactive Glasses and Glass-Ceramics for Healthcare Applications in Bone Regeneration and Tissue Engineering

“…Following this peripheral attempt, there can be identified in the main scientific data bases (e.g., Web of Science ® , Scopus ® , Pubmed ® ) significant research efforts devoted by the groups led by Jansen and van den Beucken [359,361,370,371,372], on SBG—hydroxyapatite mixed layers, and Stan and Ferreira [151,304,307,308,309,310,311,312,313,362,363,373,374], (on pure SBG thin films, with only isolated trials published by Slav et al [360] and Saino et al [364]. Recently, Stuart et al [375,376,377,378,379] debuted a series of studies on the preparation by RF-MS of resorbable phosphate bioglass (PBG) thin films that are capable of releasing various therapeutic (e.g., antimicrobial) ions in a fast, but controllable manner.…”

“…While RF-MS possesses a large number of advantages, it has also been criticised for its presumed inability to congruently reproduce with ease the composition of complex materials, including SBGs and PBGs, since the lighter species are more readily ejected from the target surface. However, by the variation of the main RF-MS deposition parameters (sputtering pressure, working atmosphere, target powder density, target-to-substrate separation distance), one can modify the composition and structure of films starting from a single target, in the pursuit of improved mechanical and biological performances [304,308,309,310,312,375,376,377,378,379]. Nevertheless, a longer pre-sputtering treatment of the target, performed prior to the film deposition process, is known to lead to the stabilisation of the sputtering processes and a more equilibrated heavier/lighter elements ratio at the target surface [312].…”

Bioglass implant-coating interactions in synthetic physiological fluids with varying degrees of biomimicry

“…[2][3][4][5][6][7][8] Currently, the bioactivity of BGs is routinely assessed through their immersion in simulated body fluid (SBF) solution, 9 a simplistic method that does not account for the complex biological processes that take place after implantation. The synthetic SBF solution introduced to the scientific community in 1990 by Kokubo et al reproduces only the inorganic composition of physiological media (ie, blood plasma).…”

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

“…The increase in life expectancy, and the higher frequency of injuries and diseases are regarded as the main factors for this growing demand in orthopaedic and dental devices. The quality of life for millions of people has been drastically improved by using hydroxyapatite (HA) and bioactive glasses (BGs) for bone repair and tissue regeneration [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]. In particular, synthetic stoichiometric hydroxyapatite (having the Ca 10 (PO 4 ) 6 (OH) 2 stoichiometry and theoretical Ca/P molar ratio of 1.67), calcium-deficient hydroxyapatite, or oxyapatite have been widely used as prominent bioactive materials in healthcare due to their excellent biocompatibility, non-toxicity and osteoconductive properties [1,2,20,21,22].…”