Corrosion Behavior and Biocompatibility of Na2EDTA-Induced Nacre Coatings on AZ91D Alloys Prepared via Hydrothermal Treatment.

Meifeng He,Hao Wang,Shuai Wang,Dan Yu,Chenggong Yuan,Wenbing Lu,Aiying Chen

doi:10.3389/fchem.2021.810886

Meifeng He, Hao Wang + Show 5 more

Open Access

https://doi.org/10.3389/fchem.2021.810886

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Abstract

An effective method for controlling the corrosion rate of Mg-based implants must be urgently developed to meet the requirements of clinical applications. As a naturally occurring osteoid material, nacre offers a strategy to endow biomedical Mg alloys with excellent biocompatibility, and corrosion resistance. In this study, pearl powder and NaH2PO4 were used as precursors to deposit coatings on AZ91D alloy substrates hydrothermally based on Na2EDTA-assisted induction. Na2EDTA-induced nacre coatings were fabricated at various pH values, and its chemical composition and microstructure were analyzed via energy-dispersive X-ray, scanning electron microscopy, and X-ray diffraction spectroscopy. The corrosion-resistant performance and cytocompatibility of the samples were evaluated via electrochemical measurements and in vitro cell experiments. Results showed that the samples hydrothermally treated under faint acid conditions present excellent corrosion resistance, whereas the samples treated under slight alkaline conditions demonstrate improved biocompatibility due to high Ca and P content and large Ca/P atomic ratio. This study provides substantial evidence of the potential value of nacre coatings in expanding the biological applications of implanted biomaterials.

Highlights

Metallic materials have appropriate physical and mechanical properties and have been extensively developed in clinical practice (Dehghanghadikolaei and Fotovvati, 2019; Wang et al, 2019; Fu et al, 2020)
EDTA acts as an intermediate bridge, which can promote the dissolution of pearl powder and induce Ca2+ in the hydrothermal solution to precipitate on the substrate
1) The nacre coatings with high crystallinity can be successfully prepared on the surface of AZ91D alloy substrates via the hydrothermal method

Summary

Introduction

Metallic materials have appropriate physical and mechanical properties and have been extensively developed in clinical practice (Dehghanghadikolaei and Fotovvati, 2019; Wang et al, 2019; Fu et al, 2020). Traditional inert metallic implants include stainless steels, titanium (Ti) alloys, and cobalt-chromium (Co-Cr) alloys, whereas biodegradable metals, such as magnesium (Mg), iron (Fe), and zinc (Zn), are applied in clinical research as a new generation of biomedical materials (Horynová et al, 2019; Su et al, 2019a; Hanas et al, 2018; Khalajabadi et al, 2016; Qin et al, 2019; Su et al, 2019b) Among these metals, Mg is the eighth-most abundant element on the surface of the earth, accounting for 1.93% of the mass of the earth’s crust, and 0.13% of the mass of the ocean (Dorozhkin, 2014; Fu et al, 2019). The degradation products of Mg-based implants can be excreted through urine and are harmless to the human body (Ali et al, 2019)

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