Mg alloy surface immobilised with caerin peptides acquires enhanced antibacterial ability and improved corrosion resistance

Abstract Magnesium (Mg) has mechanical properties similar to human bones and Mg alloy is considered ideal medical implant material. However, the high velocity of degradation inside the human inner environment severely hampers the usage of Mg alloys. In this study, caerin peptide 1.9 (F3) and a modified sequence of caerin 1.1 (F1) with anti-bacterial activity, were covalently immobilised on the surface of Mg alloys by plasma chemical click reaction. The in vitro antibacterial activity and corrosion resistance of these caerin peptide-immobilised Mg alloys were investigated in Dulbecco's Modified Eagle Medium (DMEM) solution. Un-immobilised Mg alloy sample, blank drug-sensitive tablet (BASD) and a commonly used antibiotics Tazocin were used for comparison. Results showed that peptide immobilised Mg samples showed significant improved corrosion resistance and prolonged antibacterial effect compared to non-immobilised Mg alloy and free caerin peptides. Furthermore, annealing or extruding treatment of Mg alloys improved the behaviours of corrosion resistance and antibacterial property. These results indicate that coating Mg alloy with caerin peptides improves the corrosion resistance in vitro and increases the alloy’s antibacterial ability. The mechanism underlying the prolonged antibacterial effect for annealed Mg alloys immobilised with the peptides (especially F3) remains unclear, which worth further experimental and theoretical investigation.

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Corrosion Resistance of Mg Alloy with High Zn Concentration Including Impurity Cu

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.592 ◽

2021 ◽

Vol 1016 ◽

pp. 592-597

Author(s):

Masato Ikoma ◽

Taiki Morishige ◽

Tetsuo Kikuchi ◽

Ryuichi Yoshida ◽

Toshihide Takenaka

Keyword(s):

Corrosion Resistance ◽

Corrosion Rate ◽

Mg Alloys ◽

Mg Alloy ◽

Second Phase ◽

Transportation Industry ◽

Primary Metal ◽

Cu Content ◽

Zn Concentration ◽

Lower Corrosion Rate

Mg alloys are very attractive materials for transportation industry due to their toughness and lightness. Recycling Mg alloys is desired for energy saving that otherwise would be required to produce its primary metal. However, secondary produced Mg tends to contain a few impurity elements that deteriorate its corrosion resistance. For example, contamination of Mg alloy by Cu induces second phase of Mg2Cu and it works as strong cathode, resulting in the corrosion rate rapidly increasing. It was previously reported that the corrosion resistance of Mg with impurity Cu was remarkably improved by addition of alloying element Zn. Addition of Zn into Mg formed MgZn2 phase and incorporated Cu into MgZn2 phase instead of Mg2Cu formation. In this way, since Zn serves to improve the corrosion resistance of Mg, Mg alloy with high Zn concentration may form a lot of MgZn2 and may have better corrosion resistance even with high Cu concentration. In this work, the corrosion behavior of Mg-6mass%-1mass%Al (ZA61) with different Cu content up to 1mass% was investigated. As a result, ZA61-1.0Cu had much lower corrosion rate compared to Mg-0.2%Cu and the corrosion rate was almost the same as that of pure Mg.

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Effect of Al Content in the Mg-Based Alloys on the Composition and Corrosion Resistance of Composite Hydroxide Films Formed by Steam Coating

Materials ◽

10.3390/ma12071188 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1188 ◽

Cited By ~ 1

Author(s):

Takahiro Ishizaki ◽

Tomohiro Miyashita ◽

Momo Inamura ◽

Yuma Nagashima ◽

Ai Serizawa

Keyword(s):

Aqueous Solution ◽

Corrosion Resistance ◽

Treatment Time ◽

Mg Alloys ◽

Mg Alloy ◽

Potential Range ◽

Protective Film ◽

Al Content ◽

Passive Behavior ◽

Superior Corrosion Resistance

Mg alloys are expected to be used in fields of the transportation industry because of their lightweight property, however, they show low corrosion resistance. To improve the corrosion resistance, preparation of the protective film on Mg alloys is essential. In this study, composite hydroxide films were prepared on three types of Mg alloys with different aluminum contents—that is, AZ31, AZ61, and AZ91D—by steam coating to investigate the relationship between the Mg-Al layered double hydroxide (LDH) content in the film and the Al content in the Mg alloys. Scanning electron microscopy (SEM) observation demonstrated that films were formed densely on all Mg alloy surfaces. X-ray diffraction (XRD) analyses revealed that all films prepared on AZ61 and AZ91D were composed of Mg(OH)2, AlOOH, and Mg-Al LDH, while the film containing Mg(OH)2 and Mg-Al LDH were formed only on AZ31. The Mg-Al LDH content in the film prepared on AZ61 was relatively higher than those prepared on AZ31 and AZ91D. The content of AlOOH in the film increased with an increase in the Al content in the Mg alloys. The film thickness changed depending on the treatment time and type of Mg alloy. Polarization curve measurements in 5 mass% NaCl solution demonstrated that the film prepared on the AZ61 showed complete passive behavior within the potential range of −1.0 to −0.64 V. In addition, immersion tests in 5 mass% NaCl aqueous solution for 480 h demonstrated that the film on the AZ61 had superior durability against 5 mass% NaCl aqueous solution. These results indicated that the film on the AZ61 had the most superior corrosion resistance among all samples. The results obtained in this study suggest that the LDH content in the film could be related to the corrosion resistance of the film.

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Analysis of corrosion behaviour and surface properties of plasma-sprayed composite coating of hydroxyapatite–tantalum on biodegradable Mg alloy ZK60

Journal of Composite Materials ◽

10.1177/0021998319839127 ◽

2019 ◽

Vol 53 (19) ◽

pp. 2661-2673 ◽

Cited By ~ 5

Author(s):

Balraj Singh ◽

Gurpreet Singh ◽

Buta Singh Sidhu

Keyword(s):

Corrosion Resistance ◽

Surface Properties ◽

Corrosion Behaviour ◽

Surface Hardness ◽

Mg Alloy ◽

Hydroxyapatite Coating ◽

Hydroxyapatite Coatings ◽

Plasma Sprayed ◽

Incremental Increase

Magnesium (Mg) and its alloys are promising candidates for biodegradable bio-implants. However, the excessive corrosion in the physiological environment and subsequent decline in the mechanical integrity of Mg and its alloys have limited their utility as biomaterials. In the present study, an attempt has been made to improve the corrosion resistance of Mg alloy ZK60 plasma sprayed with tantalum (Ta)-reinforced hydroxyapatite coating. The experiment was conducted with three varied levels, i.e. 10, 20 and 30 weight percent (wt%) of Ta-content in hydroxyapatite coating. The coatings were characterized and in vitro corrosion behaviour was investigated by electrochemical measurements in Ringer's solution along with the analysis of surface properties. The corrosion resistance of the Mg alloy increased with the incremental increase in Ta reinforcement in hydroxyapatite coating. An increase in the protection efficiency was analysed for the Ta-reinforced hydroxyapatite coatings (∼10%, 18% and 23% for hydroxyapatite-10Ta, hydroxyapatite-20Ta and hydroxyapatite-30Ta, respectively) as compared to the pure hydroxyapatite coating. The hydroxyapatite coating effectively increased the surface hardness of the Mg alloy and Ta reinforcement further enhanced it. Surface roughness decreased with the incremental increase in Ta-content in hydroxyapatite coating. Wettability analysis revealed the hydrophilic nature of pure hydroxyapatite and Ta-reinforced hydroxyapatite coatings. The results of the study suggest that the proposed Ta reinforcement in hydroxyapatite is potentially important for biodegradable Mg bio-implants.

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Role of calcium phosphate and bioactive glass coating on in vivo bone healing of new Mg–Zn–Ca implant

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-021-06510-0 ◽

2021 ◽

Vol 32 (5) ◽

Author(s):

Arnab Mahato ◽

Munmun De ◽

Promita Bhattacharjee ◽

Vinod Kumar ◽

Prasenjit Mukherjee ◽

...

Keyword(s):

Bioactive Glass ◽

Bone Healing ◽

Rabbit Model ◽

Mg Alloy ◽

Alloy Sample ◽

Apatite Formation ◽

Air Plasma

AbstractPresent investigation focuses on development and detailed characterization of a new Mg alloy sample (BM) with and without coating of hydroxyapatite (BMH) and bioactive glass (BMG) by air plasma spray method. After detailed mechano-physico-chemical characterization of powders and coated samples, electrochemical corrosion and SBF immersion tests were carried out. Detailed in vitro characterizations for cell viability were undertaken using MG-63 cell line followed by in vivo tests in rabbit model for studying bone healing up to 60 days. Starting current density increases from BM to BMH to BMG indicating highest resistance towards corrosion in case of BMG samples, however BMH also showed highest icorr value suggesting slowest rate of corrosion than BM and BMG samples. Dissolution of calcium ion in case of BMH and BMG control formation of apatite phases on surface. Ca2+ ions of coatings and from SBF solution underwent reduction reaction simultaneously with conversion of Mg to MgCl2 releasing OH− in the solution, which increases pH. Viability and propagation of human osteoblast-like cells was verified using confocal microscopy observations and from expression of bone specific genes. Alkaline phosphatase assay and ARS staining indicate cell proliferation and production of neo-osseous tissue matrix. In vivo, based on histology of heart, kidney and liver, and immune response of IL-2, IL-6 and TNFα, all the materials show no adverse effects in body system. The bone creation was observed to be more for BMH. Although both BMH and BMG show rays of possibilities in early new bone formation and tough bone–implant bonding at interface as compared to bare Mg alloy, however, BMG showed better well-sprayed coating covering on substrate and resistance against corrosion prior implanting in vivo. Also, better apatite formation on this sample makes it more favourable implant.

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Mg alloy surface immobilised with caerin peptides acquires enhanced antibacterial ability and putatively improved corrosion resistance

Materials Science and Engineering C ◽

10.1016/j.msec.2020.111819 ◽

2021 ◽

Vol 121 ◽

pp. 111819

Author(s):

Tianfang Wang ◽

Guoying Ni ◽

Tsuyoshi Furushima ◽

Hui Diao ◽

Pingping Zhang ◽

...

Keyword(s):

Corrosion Resistance ◽

Mg Alloy ◽

Alloy Surface ◽

Antibacterial Ability

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Effects of Interaction of (NaPO3)6 and NaH2PO4 on Ca/P of MAO Bio-Ceramic Coating of ZK60 Mg Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.21 ◽

2013 ◽

Vol 745-746 ◽

pp. 21-27

Author(s):

Cui Ling Du ◽

Jing Chen ◽

Bin Bin Cao ◽

Lei Xu ◽

Sheng Lu

Keyword(s):

Corrosion Resistance ◽

Ceramic Coating ◽

Energy Dispersive Spectrometer ◽

Mg Alloy ◽

Molar Ratio ◽

X Ray Diffraction ◽

Orthogonal Experiments ◽

Micro Arc Oxidation ◽

Evolution Phase

Micro-arc oxidation (MAO) process was conducted on ZK60 Mg alloy in a basic biologic electrolyte composed of silicate by addition of (NaPO3)6 and NaH2PO4. The microstructural evolution, phase composition and in vitro corrosion resistance of the coating were investigated by means of scanning electron microscopy (SEM) coupled with an energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results revealed that bioactive elements Mg, Ca, P and Si were remained in the bio-ceramic coating which can be prepared in suitable biologic electrolyte. For the interaction of (NaPO3)6 and NaH2PO4 , the Ca/P molar ratio of the coating in the optimized biologic electrolyte reached to 1.24 by L9 (34) orthogonal experiments. Compared with the bare ZK60 Mg alloy, the corrosion resistance of the optimized sample in 37 Ringers solution was improved by 4 orders.

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