Sol-Gel Prepared Niobium Oxide and Silicon Oxide Coatings on 316L Stainless Steel for Biomedical Applications

Date

2016-09

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New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.

Abstract

Medical implants have become an important component in the preventative and reconstructive treatment of patients for a variety of health problems. However, lack of biocompatibility, failure of implant due to corrosion and risk of postoperative infection pose as major challenges for their clinical applications. In order to counteract the above problems sol gel prepared niobium oxide and silicon oxide coatings were deposited on 316L stainless steel by spin coating. The preliminary work consisted of morphology, structure and composition analyses of these coatings by FESEM, XPS and GIXRD. Bioactivity was determined through (1) the analysis of calcium phosphate formation at the surface of coatings as a function of simulated body fluid (SBF) reaction time, (2) viability of osteoblast cells using MTT assay (3) osteoblast cell adhesion and proliferation using FESEM for coated and uncoated 316L stainless steel. Deposition of calcium phosphate layer was confirmed by EDS and SEM analysis. Corrosion resistances of coated and uncoated stainless steel were evaluated in three different physiological environments such as SBF (pH 7.4), water (pH 7) and SGF (pH 1.2) for different time periods. The reaction of samples was observed in the form of cracking and peeling of coatings, formation of corrosion product, passivation of metallic substrate. The changes in morphology and surface chemistry with time of immersion were evaluated through FESEM along with XPS analysis. Since electrochemical analysis such as open circuit potential (OCP) and linear polarization resistance (Rp) strongly depended on the surface condition of the metallic implant these measurements were performed on an externally corroded sample without disturbing the surface. The results obtained by LPR could give information about the influence of corrosive media on the metallic implant and instantaneous corrosion rate with time of immersion. A very large portion of implant related infection is caused by Staphylococcus aureus (S.Aureus). To combat the effect of S.aureus, erythromycin was incorporated into niobium oxide coatings. Two innovative techniques (solution route and incipient wetness impregnation route) were adopted for synthesis of drug containing niobium oxide systems. Varying concentration of (10, 40 and 80mg/ml) erythromycin was incorporated and experiments were conducted to evaluate the release of antibiotic after 3 and 34 hours followed by their efficiency via bacterial viability and adhesion on surface.

Description

Advisory committee members: Anthony Wren, David Lipke, Yiquan Wu. Dissertation completed in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Materials Science and Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University

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