Development and In Vitro Biodegradation of Biomimetic Zwitterionic Phosphorylcholine Chitosan Coating on Zn1Mg Alloy

Abstract

Zinc (Zn) alloys are promising alternatives to magnesium (Mg)-and iron (Fe)-based alloys because of their moderate corrosion rate and superior biocompatibility. To reduce the mass release of Zn 2+ and improve the biocompatibility of Zn implants, the biomimetic zwitterionic polymer layer (phosphorylcholine chitosanPCCs) was immobilized on the plasma-treated Zn1Mg surface. It is the chemical bonds between the −NH 2 groups of the PCCs chain and O−CO (CO) groups on the plasma-treated Zn1Mg (Zn1Mg-PP) that contributes to the strong bonding strength between the film and the substrate, by which the PCCs (approx. 200 nm thick) layer can bear a 5.93 N normal load. The electrochemical impedance spectroscopy (EIS) results showed that the PCCs layer remarkably increased the resistance against corrosion attack, protecting substrates from over-quick degradation, and the protective effect of the layer with a thickness of 200 nm lasts for about 24 h. The corrosion products of Zn1Mg-PP-PCC in NaCl solution were determined as Zn 5 (OH) 8 Cl 2 •H 2 O and Zn 3 (PO 4 ) 2 . Besides, the bulk Zn1Mg can trigger more aggressive macrophage activity, while the surface of Zn1Mg-PP and Zn1Mg-PP-PCC and their corrosion products (Zn 3 (PO 4 ) 2 ) tend to promote the differentiation of macrophages into the M2 phenotype, which is beneficial for implant applications.

Improving anti‐Gram‐positive‐bacterial performance and osteogenesis for zinc alloy via mussel mimetic polydopamine with non‐antibiotic lysozyme and parathyroid hormone

“…Staphylococcus aureus ( S. aureus ) was used as Gram‐positive bacteria, and Escherichia coli ( E. coli ) was used as Gram‐negative bacteria. The antibacterial properties of the samples were evaluated by the diffusion plate method [27]. 100 μL of bacterial suspension with a concentration of 10 6 CFU/mL were evenly distributed on agar dishes, and the samples were placed at the centre of dishes.…”

Imidazole functionalized photo-crosslinked aliphatic polycarbonate drug-eluting coatings on zinc alloys for osteogenesis, angiogenesis, and bacteriostasis in bone regeneration

“…Besides, due to the intricately connection between tissues and surface characteristics of implants, surface modification still plays an important role in adjusting surface properties of Zn alloys while preserving their inherent bulk material performance. Recent advances in surface modification for orthopedic used Zn alloys included surface coatings [ [28] , [29] , [30] , [31] ], biomimetic deposition [ 32 , 33 ], stabilization treatment [ 34 ], microarc oxidation [ 35 ], atomic layer deposition [ 17 ], magnetron sputtering [ 36 ], and sandblasting [ 37 ]. Surface coating modification, especially polymer drug-eluting coatings, is an effective approach to regulate the degradation behavior of zinc alloys and accelerate the process of fibrocartilaginous callus formation and vascularization for medical implant.…”

Micro/Nano‐Structured Metal–Organic/Inorganic Hybrid Coatings on Biodegradable Zn for Osteogenic and Biocompatible Improvement

“…Surface modification has been proved as one of the most effective and attractive strategies to improve or tailor the surface properties of biodegradable metals. For orthopedic implant applications, various surface modification methods have been employed to construct different types of coatings on metallic Zn; the reported coatings include polymer, [ 7c,8 ] composite, [ 7e,g ] metallic oxide, [ 7a,d ] inorganic phosphate coatings, and others. [ 7e,g,9 ] Although these coatings have been reported to slow down the corrosion rate (CR) of Zn and improve its biocompatibility, they are still short of satisfactory osteogenic properties for the target bone healing and regeneration.…”