Orthopaedic bioactive glass/chitosan composites coated 316L stainless steel by green electrophoretic co-deposition

Abstract

Single-step electrophoretic co-deposition (EPD) technique was used to enhance the bioactivity of the 316L stainless steel (316L SS) surface by bioactive glass/chitosan composite coatings. Two modified glass compositions of Bioglass® by the addition of boron were utilized to prepare such composite layers, and the Bioglass® was synthesized for comparison. Different EPD coating factors were studied. Namely, voltage, time, glass powder, and chitosan concentrations, to obtain crack-free and good adhesive coatings. The achieved surfaces were characterized by SEM/EDX, TGA, XRD and FTIR and their wettability and roughness were investigated. The in vitro bioactivity of the coated metals was compared in simulated body fluid (SBF) and Dulbecco's modified eagle medium (DMEM) for up to 15days. The electrochemical corrosion behavior of the coated metals was evaluated using potentiodynamic polarisation and impedance techniques in the two biological solutions SBF and DMEM at 37°C. The results showed that the achieved coatings were uniform, homogenous and crack-free with desirable thickness. Moreover, the coating layers were exhibited by very high wettability, and their roughness values ranged from 170±18 to 234±17μm. The in vitro bioactivities proved that the coating layers represented a better ability to form hydroxyapatite crystals on their surfaces in SBF than in DMEM. The corrosion resistance of 316L SS was improved by the bioactive composite coatings.