Mg–Phenolic Network Strategy for Enhancing Corrosion Resistance and Osteocompatibility of Degradable Magnesium Alloys

Abstract

Magnesium-based alloys are the most widely used materials for degradable metallic implants and have considerable potential for bone applications owing to their excellent stimulating effect on osteogenesis. However, their high corrosion rate limits their structural stability and causes oxygen deficiency and an excessive increase in the pH around the defect area during bone healing. Magnesium oxides, which are the main corrosion products of Mg, are nontoxic materials with useful effects on new bone formation and pH neutralization. Metal–phenolic networks were introduced recently as a cost-effective and efficient surface modifier and were fabricated by deposition of nanosized metal oxides on different types of substrates using the chemical reaction between phenolic groups and metallic ions. In this study, magnesium oxide films were formed successfully on a Mg-based substrate using Mg–phenolic networks. The effects of various coating parameters on the surface morphology, corrosion resistance, degradation behavior, wettability, and osteocompatibility of degradable metallic materials after surface modification with Mg–phenolic networks were thoroughly investigated for the first time. The results showed that the initial concentration of Mg ions was the main parameter affecting the corrosion resistance, which was almost as much as 3 times that of uncoated samples. Additionally, cytotoxicity and viability assessment and observation of the morphological changes in bonelike cells showed that the in vitro osteocompatibility was significantly enhanced by coatings with Mg concentrations of 2.4–3.6 mg mL–1. Finally, in vivo animal studies using the rat calvarial defect model confirmed that the proposed coating method mitigated the formation of gas cavities around the implantation area by reducing the corrosion rate of the Mg-based implant. The nanosized metal oxides produced by the Mg–phenolic network significantly improved the biodegradability and osteocompatibility of Mg alloys, suggesting a potential approach to advancing the clinical application of Mg alloys.

Application of bioactive metal ions in the treatment of bone defects

“…Various metal ions, such as Cu 2+ , Mg 2+ , Sr 2+ , gallium ions (Ga 3+ ), and Co 2+ , have been found to improve the microenvironment of bone defects and promote bone repair. [18][19][20][21][22] The mechanisms of promoting the osteogenesis of these metal ions are numerous and complex. 23 We will discuss the functionality of metal ions in the treatment of bone defects from the aspects of directly promoting bone tissue regeneration, inhibiting osteoclasts, promoting angiogenesis, and improving the microenvironment through a local antibacterial effect (Table 1).…”

Zn-contained mussel-inspired film on Mg alloy for inhibiting bacterial infection and promoting bone regeneration

“…The content of Zn in the surface of Zn-contained PDA films ranged from 1.81 to 2.58 at%. It was widely reported that metal ions can be chelated with phenolic groups [ 39 , 40 ], whereas a dopamine molecule contains two phenolic hydroxyl groups. Therefore, the Zn ions can easy be chelated in PDA film.…”

Customized Barrier Membrane (Titanium Alloy, Poly Ether-Ether Ketone and Unsintered Hydroxyapatite/Poly-l-Lactide) for Guided Bone Regeneration

“…Asgari et al prepared a magnesium oxide film coating on a Mg-based substrate and established a rat calvarial defect model. Their results revealed the improved osteo-compatibility and biodegradability of magnesium alloys ( Asgari et al, 2019 ). Zinc-based alloys can improve the low strength and brittleness of pure zinc and provide a novel biodegradable material for orthopedic applications.…”