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A new strategy for developing chitosan conversion coating on magnesium substrates for orthopedic implants.

A new strategy for developing chitosan conversion coating on magnesium substrates for orthopedic implants.

Authors :
Francis, A.
Yang, Y.
Boccaccini, A.R.
Source :
Applied Surface Science. Feb2019, Vol. 466, p854-862. 9p.
Publication Year :
2019

Abstract

Highlights • Integrating the surface of Mg as a part of corrosion resistant coating via Mg-chitosan complexation process. • Chelating and depositing a CHI/BG composite coating onto Mg via a chemical conversion process at 75 °C. • CHI-based coating containing bioactive glass (BG) on Mg developed. • CHI-BG coatings exhibited bioactive properties upon immersion in SBF. Abstract Chitosan as a natural biopolymer was immobilized and chelating-deposited with and without bioactive glass (BG) onto Mg substrates by means of a chemical conversion process at 75 °C to provide anti-corrosion properties, good adhesion and biocompatibility. The aim of the present work was to integrate the surface of biodegradable Mg as a part of the corrosion resistant coating via metal-chitosan complexation process. The surface morphology and composition of the coatings were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results provided evidence of the formation of a chitosan coating as well as its chelating reaction and immobilization on magnesium by a chemical conversion process. The non-alkalization of the chitosan solution was ascribed to the protective layer of Mg (II)-chitosan complex, which inhibits the further migration of Mg ions. The in vitro bioactivity of both chitosan (CHI)-coated and chitosan/BG (CHI/BG)-coated surfaces in simulated body fluid (SBF) proved the complete retention of chitosan and BG on the magnesium substrates. The XRD analysis of the (CHI/BG) coating after 2 weeks immersion in SBF showed mainly the formation of magnesium hydrogen phosphate hexahydrate and undetected amorphous (Ca, Mg) phosphate. The present study represents a novel attempt to modify the surface of Mg by a simple, one-step chemical conversion treatment in chitosan to form a Mg (II)-chitosan complex layer. Mechanisms for the Mg-chitosan complexation process and for the coating bioactivity behavior in SBF were discussed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01694332
Volume :
466
Database :
Academic Search Index
Journal :
Applied Surface Science
Publication Type :
Academic Journal
Accession number :
133462176
Full Text :
https://doi.org/10.1016/j.apsusc.2018.10.002