In vitro biological and antimicrobial properties of chitosan-based bioceramic coatings on zirconium

Salim Levent Aktug,Kultigin Cavusoglu,Metin Usta,Selin Kalkan,Salih Durdu

doi:10.1038/s41598-021-94502-z

Salim Levent Aktug, Kultigin Cavusoglu + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-94502-z

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Abstract

Ca-based porous and rough bioceramic surfaces were coated onto zirconium by micro-arc oxidation (MAO). Subsequently, the MAO-coated zirconium surfaces were covered with an antimicrobial chitosan layer via the dip coating method to develop an antimicrobial, bioactive, and biocompatible composite biopolymer and bioceramic layer for implant applications. Cubic ZrO2, metastable Ca0.15Zr0.85O1.85, and Ca3(PO4)2 were detected on the MAO surface by powder-XRD. The existence of chitosan on the MAO-coated Zr surfaces was verified by FTIR. The micropores and thermal cracks on the bioceramic MAO surface were sealed using a chitosan coating, where the MAO surface was porous and rough. All elements such as Zr, O, Ca, P, and C were homogenously distributed across both surfaces. Moreover, both surfaces indicated hydrophobic properties. However, the contact angle of the MAO surface was lower than that of the chitosan-based MAO surface. In vitro bioactivity on both surfaces was investigated via XRD, SEM, and EDX analyses post-immersion in simulated body fluid (SBF) for 14 days. In vitro bioactivity was significantly enhanced on the chitosan-based MAO surface with respect to the MAO surface. In vitro microbial adhesions on the chitosan-based MAO surfaces were lower than the MAO surfaces for Staphylococcus aureus and Escherichia coli.

Highlights

Ca-based porous and rough bioceramic surfaces were coated onto zirconium by micro-arc oxidation (MAO)
The mechanism by which the hydroxyapatite structure formed on different surface types such as undoped and antimicrobial Ag, Cu, and Zn-doped MAO surfaces post-immersion in simulated body fluid (SBF) have been discussed in detail in our previous studies[7,8,9,47,48]
Munteanu et al found that chitosan-coated polyethylene surfaces provided 100% inhibition against S. enteritidis after 48 h of interaction, while providing 96.43% inhibition against E. coli 74. Another important result obtained from the antimicrobial test is that chitosan-coated MAO surfaces have a greater effect against E. coli than S. aureus

Summary

Introduction

Ca-based porous and rough bioceramic surfaces were coated onto zirconium by micro-arc oxidation (MAO). To our knowledge there has been no previous study on the fabrication and investigation of an antimicrobial chitosan-based biopolymer structure on MAO-coated Zr surfaces to date. Natural chitosan-based MAO coatings with antimicrobial and bioactive properties were produced on Zr metal for the first time in the literature.

Results

Conclusion