Antibacterial improvement with multilayer of bio-composite coatings produced by electrophoretic deposition

Abstract

In this study, multi-structured coatings of biocompatible and antibacterial materials on a 316L stainless steel (SS) implant have been electrophoretically deposited for orthopedic applications. Two layers of composite coatings have been deposited; the first layer of composite coating biopolymer layer consists of (chitosan with Gelatin) and the second composite coating layer of bio-ceramic comprises Hydroxyapatite with chitosan. The first layer was deposited at (3 g/L concentration of Gelatin, 20 voltage, and 3 min and 0.5 g/L chitosan) parameters, and the second layer was deposited at (6 g/L, 40 voltage, 1 min, and 0.5 g/L chitosan) parameters. In this study, the stability of the suspension was evaluated using the Zeta potential test, which manifested good stability. The adhesion strength between the composite coatings' first layer and the 316L stainless steel substrate, as well as between the coating layers themselves, was determined using the Tape test, and the removal area for the first layer was 8.06% while for the second layer was 6.01%. The wettability test elucidated for the 316L stainless steel and first coating layer and the second coating layer, the second composite coating layer became super hydrophilic, and a very high wettability was exhibited with multilayer coating. Scanning electron microscopy showed that the surface's topology revealed a homogenous and defect-free composite coating. The result of the antibacterial efficiency of the 316L SS substrate improved as the number of coating composite layers increased, and the resistance to corrosion of 316L SS enhanced as the number of coating composite layers increased.

Keywords

• electrophoretic deposition
• gelatin
• chitosan
• ha
• epd