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Magnesium alloys are candidates to be used as biodegradable biomaterials for producing medical device. Their use is restricted due to the high degradation rate in physiological media. To contribute to solving this problem, a polydopamine (PDOPA) layer could be used to increase adhesion between the metallic substrate and external organic coating. In...
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The aim of this study was to investigate the influence of different process parameters as chemical composition, the pH value and immersion time on the corrosion of the some TiMoNb alloys, using different electrochemical techniques such as: cyclic voltammetry, open circuit potential (OCP) measurement, polarization curves and electrochemical impedanc...
Citations
... Tantalum-PDA-Mg2 shows the highest ion release and excellent biocompatibility, adhesion, angiogenesis, and osteogenesis [56]. Although magnesium alloys are applied as biodegradable biomaterials for medical device production, their use is restricted because of the high degradation rate, and a PDA layer can increase the adhesion between the external organic coating and metallic substrate and decrease the substrate degradation rate [57]. Our findings also manifested that PDA coating in PLGA/ MgO (10%) scaffolds reduced the cytotoxicity of scaffolds and promoted osteogenic differentiation of BMSCs. ...
Introduction
Bones are easily damaged. Biomimetic scaffolds are involved in tissue engineering. This study explored polydopamine (PDA)-coated poly lactic-co-glycolic acid (PLGA)-magnesium oxide (MgO) scaffold properties and its effects on bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation.
Methods
PLGA/MgO scaffolds were prepared by low-temperature 3D printing technology and PDA coatings were prepared by immersion method. Scaffold structure was observed by scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS), fourier transform infrared spectrometer (FTIR). Scaffold hydrophilicity, compressive/elastic modulus, and degradation rates were analyzed by water contact angle measurement, mechanical tests, and simulated-body fluid immersion. Rat BMSCs were cultured in scaffold extract. Cell activity on days 1, 3, and 7 was detected by MTT. Cells were induced by osteogenic differentiation, followed by evaluation of alkaline phosphatase (ALP) activity on days 3, 7, and 14 of induction and Osteocalcin, Osteocalcin, and Collagen I expressions.
Results
The prepared PLGA/MgO scaffolds had dense microparticles. With the increase of MgO contents, the hydrophilicity was enhanced, scaffold degradation rate was accelerated, magnesium ion release rate and scaffold extract pH value were increased, and cytotoxicity was less when magnesium mass ratio was less than 10%. Compared with other scaffolds, compressive and elastic modulus of PLGA/MgO (10%) scaffolds were increased; BMSCs incubated with PLGA/MgO (10%) scaffold extract had higher ALP activity and Osteocalcin, Osteopontin, and Collagen I expressions. PDA coating was prepared in PLGA/MgO (10%) scaffolds and the mechanical properties were not affected. PLGA/MgO (10%)/PDA scaffolds had better hydrophilicity and biocompatibility and promoted BMSC osteogenic differentiation.
Conclusion
Low-temperature 3D printing PLGA/MgO (10%)/PDA scaffolds had good hydrophilicity and biocompatibility, and were conducive to BMSC osteogenic differentiation.
... Magnesium alloys are commonly used materials in various industrial areas, especially in biomaterials, due to their lightweight nature and low density. Types such as ZK60, AZ91, and AZ31 have been extensively studied for their biocompatibility and mechanical properties that closely resemble cortical bone [5][6][7][8][9][10][11][12]. Additionally, the similar toughness values of these alloys to bone help prevent the problem of stress shielding and do not damage healthy bone [7]. ...
... Furthermore, HA has become a sought-after and reliable biomaterial due to its presence in the structure of bone, providing superior bonding between the implant and surrounding tissue [39][40][41][42]. Even traditional biomaterials such as Ti6Al4V are coated to strengthen the bond with the tissue [5,43,44]. Existing literature suggests that HA coating helps prevent the corrosive effect of body fluids [45]. ...
The corrosion and bacterial behavior of AZ91 magnesium alloy coated with sol–gel-deposited amorphous tantalum oxide and hydroxyapatite have been investigated. The objective was to assess the potential suitability of AZ91 for permanent prosthesis applications. The coatings were applied in layered and hybrid configurations and characterized using various techniques including X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectrometry, and drop analyses. The antibacterial properties were evaluated through interactions with Staphylococcus aureus and Escherichia coli strains. Mechanical properties and adhesion were determined via linear scratch tests, and electrochemical corrosion tests were conducted in different media. The release of aluminum ions from the samples in Dulbecco’s Modified Eagle’s Medium was monitored over 28 days. The findings revealed that the amorphous tantalum oxide coating, particularly in combination with hydroxyapatite, improved antibacterial properties and positively influenced corrosion and scratch resistance. The layered and hybrid coatings demonstrated the highest corrosion resistance. The release of aluminum ions remained within acceptable levels in the tested medium. Overall, the study provides valuable insights into the potential of sol–gel coatings on AZ91 for prosthetic applications, considering antibacterial behavior, corrosion resistance, and aluminum release.
... Polymer or organic coatings are more promising than inorganic coatings because of their capacity for biocompatibility, degradation, self-healing ability, drug release, and cell response-induced capabilities such as adhesion, differentiation, and proliferation [83]. Examples of polymeric or organic coatings include polycaprolactone (PCL) [84][85][86][87], polydopamine (PDA) [88], polylactic acid (PLA) [17,[89][90][91][92][93], poly (L-lactic acid) (PLLA) [94], poly (lactide-co-glycolic) acid (PLGA) [95][96][97][98], silane [99][100][101], chitosan (CS) [102], hyaluronic acid (HA) [103], and other representative polymers [104]. Various methods have been suggested for the fabrication of polymeric coatings on Mg alloys, such as spin coating, dipping coating, layer-by-layer assembly (LbL), and electrochemical methods (electrochemical grafting, electrodeposition, and electro polymerization). ...
The aim of the present paper was to evaluate the effect of hydroxyapatite coatings on the two types of Mg–Zn–Ag alloys as a possible solution to control magnesium alloy degradation. The coatings were prepared by the radio frequency magnetron sputtering method at a deposition temperature of 300 °C. To perform this evaluation, the coated alloys were immersed in a simulated body fluid solution at body temperature (37 ± 0.5 °C) to determine the corrosion resistance through electrochemical and immersion tests. Moreover, the investigation also consisted of the evaluation of microchemical, mechanical, and morphological properties. The deposition temperature of 300 °C was enough to obtain a crystalline hydroxyapatite structure with a Ca/P ratio close to the stochiometric one. The adhesion of coatings was not influenced by the nature of Mg–Zn–Ag alloys, so similar values for both coated alloys were found. The results showed that the coating was homogonous deposited on the Mg–Zn–Ag alloys and the corrosion resistance of uncoated magnesium alloys was improved.
... However, the main drawbacks of the clinical use of magnesium-based alloys are their fast corrosion, hydrogen release, and the increase in the alkalinity of body fluid during the degradation process. Therefore, great interest is directed to the control of the degradation rate of Mg alloys including through the application of bio-inspired [5] or biodegradable polymeric coatings [6,7] or an oxide layer obtained by electrochemical treatments [8]. In addition to the increased corrosion resistance, Plasma electrolytic oxidation (PEO) treatment, also known as microarc oxidation (MAO), is a flexible and environmental friendliness process [9]. ...
Magnesium alloys are an exciting challenge for the biomaterials field given their well-established biodegradability and biocompatibility. However, when exposed to biological fluids, their rapid degradation and hydrogen release are the main drawbacks for clinical applications. This work aimed to investigate the influence of the current density applied during the plasma electrolytic oxidation (PEO) treatment on the durability of an AZ31 magnesium alloy. In particular, specific interest was directed to the degradation rate undergone by the PEO coating, obtained under two different current density conditions, when exposed to Hank’s solution at 37 °C to simulate the physiological environment, employing the techniques of potentiodynamic polarization and electrochemical impedance spectroscopy. Experimental results highlighted that the plasma electrolytic oxidation technique resulted in an improvement in the corrosion resistance of the magnesium alloy in the test solution. The current density affected the morphology of the coating. In particular, the anodic oxide coating obtained by applying the highest current density showed a higher thickness and fewer but larger pores, while the lowest current density generated a thinner PEO coating characterized by several but smaller pores. Surprisingly, the best corrosion resistance has been exhibited by the anodic oxide coating grown at the highest current density.
... A second strategy is to introduce the bioinspired bioactive molecule, including polydopamine (PDA) [60][61][62], hyaluronic acid (HA) [30][31][32][33], chitosan (CS) [63], heparin [64], vascular endothelial growth factor (VEGF) [65], stem cell homing factor (SDF-1α) [66,67], Arg-Glu-Asp-Val (REDV) [68], and other representative bioactive molecules. Bioinspired bioactive surfaces are more prominent than bioinspired inorganic structure surfaces in the field of implanted Mg-based stents due to their degradation ability, biocompatibility, and modulation of cell behavior (e.g., adhesion, proliferation, and differentiation). ...
... The bioinspired bioactive surfaces can be created via bioactive molecular interactions be-Crystals 2022, 12, 1761 5 of 8 tween functional groups and Mg-based stents surfaces, such as electrostatic interactions or intermolecular forces. For instance, PDA, which was inspired by mussels' feet with a high-adhesion protein, has emerged as one of the most widely employed techniques for functionalizing the surfaces of magnesium alloys [62]. The bioinspired PDA surface is beneficial in enhancing the attachment, proliferation, and viability of ECs. ...
Magnesium alloys have attracted considerable interest as prospective biodegradable materials in cardiovascular stents because of their metal mechanical properties and biocompatibility. However, fast degradation and slow endothelialization results in the premature disintegration of mechanical integrity and the restenosis of implanted Mg-based stents, which is the primary hurdle limiting their predicted clinical applicability. The development of bioinspired strategies is a burgeoning area in cardiovascular stents’ fields of research. Inspired by the unique features of lotus leaves, pitcher plants, healthy endothelial cells (ECs), marine mussels, and extracellular matrix, various bioinspired strategies have been developed to build innovative artificial materials with tremendous promise for medicinal applications. This perspective focuses on bioinspired strategies to provide innovative ideas for reducing corrosion resistance and accelerating endothelialization. The bioinspired strategies are envisaged to serve as a significant reference for future research on Mg-based medical devices.
... However, the defect of magnesium and its alloys is that they are susceptible to corrosion in the human environment. They degrade too quickly and lose mechanical strength prematurely [3]. Therefore, regulating the degradation characteristics of Mg alloys is the key to their wider clinical application. ...
Photo-thermal antibacterial properties have attracted much attention in the biomedical field because of their higher antibacterial efficiency. Through fabricating micro-arc oxidation coatings with different treating current densities set on a Mg-Zn-Ca alloy, the present study tried to systematically investigate and optimize the corrosion resistance and photo-thermal antibacterial properties of MAO coatings. The results indicated that different current densities had great influence on the corrosion resistance and photo-thermal property of the MAO coatings, and a current density at 30 A·dm−2 exhibited the best corrosion resistance, light absorption capacity at 808 nm, and photo-thermal capability, simultaneously with good antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This photo-thermal property of MAO coatings was probably related to the effect of current density on MgO content in the coating that could promote the separation of photo-generated electron carriers and hinder the recombination of photo-generated electron carriers and holes.
... To further improve cell adhesion, proliferation, and migration, the bioinspired polydopamine surface can also operate as a flexible substrate for the following surface-mediated reactions [78][79][80][81]. For instance, Zhou et al. [65] created a bioinspired protective surface on AZ31 magnesium alloy based on the hydrothermal treatment of hydroxyapatite and polydopamine. ...
Magnesium alloys are regarded as potential candidates in industrial and biomedical applications because of their excellent mechanical properties and biodegradability. However, the excessive degradation rate of magnesium alloys can cause a premature disintegration of mechanical integrity, which is the main bottleneck that limits applications. Inspired by nature, various novel surface designs provide a clever strategy to regulate the corrosion behavior of magnesium alloys. This review extensively discusses bioinspired surface designs to reduce corrosion resistance and realize functionalization, so as to offer new ideas with great potential for biomedical applications. Future research on corrosion resistance is expected to benefit greatly from the bioinspired surface designs.
... Moreover, an inductive loop appeared on the Nyquist spectrum at the low-frequency region, which is attributed to the pitting corrosion and adsorption/desorption of intermediates on the metal substrate [77]. The poor corrosion resistance of the SF-CNC coating on AZ31-OH is most likely because of the weak bonding between the polymer layer and the underneath metal substrate, which could result in interfacial delamination and loss of corrosion protection properties [78]. This assumption is further supported by the high magnified cross-sectional SEM images of the SF-CNC coating, where several cleavages were observed sporadically along the metal/coating interface, when the SF-CNC coating was applied on the AZ31-OH surface with no subsequent PD modification. ...
... Besides, no inductive loop was observed at the lower frequencies, suggesting the presence of a stable corrosion protective layer on the metal surface [79]. A similar enhancement effect of intermediary PD layer on the corrosion protection performance of an externally applied polymeric coating has been previously reported in several studies and attributed to the higher adhesion at substrate/coating interface resulted from the chemical interactions as well as mechanical anchoring between the organic coating and the PD surface [70,78,80,81]. The results clearly indicated that the presence of the intermediary PD layer with improved adhesiveness to the secondary coating is decisive to acquire a notable corrosion protection offered by the SF-CNC coating. ...
In this work, a novel coating material based on silk fibroin (SF) and cellulose nanocrystals (CNCs) was developed on biodegradable AZ31 Mg alloy and assessed for corrosion resistance and biocompatibility. Before the application of the coating, AZ31 substrate was modified with a layer of polydopamine to enhance the adhesion of the protective coating to the metal surface as confirmed by the adhesion tape test. SEM images revealed the formation of a defect-free and uniform SF-CNC coating with a thickness of 11.2 ± 2.5 μm on AZ31 alloy. The results of the electrochemical corrosion and in vitro immersion tests clearly demonstrated an enhanced corrosion resistance of the SF coating after the incorporation of CNCs. Compared to the unmodified Mg alloy, the SF-CNC coated AZ31 exhibited a remarkably improved cytocompatibility with a viability of 114% and excellent adhesion and spreading of human fetal osteoblast cells onto the coating surface. The findings of this work highlight the great potential of SF and CNC as bio-based nature-derived anticorrosive nanofillers for fabrication of protective and biocompatible coatings on Mg-based biodegradable orthopedic implants.
... 15,16 Mesoporous polydopamine (MPDA), spontaneously polymerized by dopamine, displays striking properties in optics, electricity, magnetics, biocompatibility, and biodegradability and has gained much attention for biomedical applications. 17,18 MPDA has been reported to load chemotherapy agents for enhanced anticancer therapy and reduced side effects. 19,20 In addition, MPDA shows strong near-infrared (NIR) absorption, efficiently converts NIR light into heat to kill cancer cells, and finally realizes synergistic chemotherapy and photothermal therapy of cancers. ...
Objectives
It is imperative to develop efficient strategies on the treatment of prostate cancer. Here, we constructed multifunctional nanoparticles, namely AS1411@MPDA-DTX (AMD) for targeted and synergistic chemotherapy/photothermal therapy of prostate cancer.
Materials and Methods
Mesoporous polydopamine (MPDA) nanoparticles were prepared by a one-pot synthesis method, DTX was loaded through incubation, and AS1411 aptamer was modified onto MPDA by the covalent reaction. The prepared nanoparticles were characterized by ultra-micro spectrophotometer, Fourier transform infrared spectra, transmission electron microscope, and so on. The targeting ability was detected by selective uptake and cell killing. The mechanism of AMD-mediated synergistic therapy was detected by Western blot and immunofluorescence.
Results
The prepared nanoparticles can be easily synthesized and possessed excellent water solubility, stability, and controlled drug release ability, preferentially in acidic context. Based on in vitro and in vivo results, the nanoparticles can efficiently target prostate cancer cells, promote DTX internalization, and enhance the antitumor effects of chemo-photothermal therapy strategies under the NIR laser irradiation.
Conclusions
As a multifunctional nanoplatform, AS1411@MPDA-DTX could efficiently target prostate cancer cells, promote DTX internalization, and synergistically enhance the antiprostate cancer efficiency by combining with NIR irradiation.
... Results from our previous studies have confirmed that LDH coating can improve in vitro and in vivo corrosion resistance of Mg-based materials[27,30]. PDA is a compact layer of polymer that can effectively prevent the penetration of liquid molecules and block the electron transfer between Mg substrate and corrosive solution, thus improving the corrosion resistance of the material[21,31,32]. ...
Primary malignant bone tumors can be life-threatening. Surgical resection of tumor plus chemotherapy is the standard clinical treatment. However, postoperative recovery is hindered due to tumor recurrence caused by residual tumor cells and bone defect caused by resection of tumor tissue. Herein, a multifunctional mussel-inspired film was fabricated on Mg alloy, that is, an inner hydrothermal-treated layer, a middle layer of polydopamine, and an outer layer of doxorubicin. The modified Mg alloy showed excellent photothermal effect and thermal/pH-controlled release of doxorubicin. The synergistic effect of chemotherapy and photothermal therapy enabled the modified Mg alloy to kill bone tumor in vitro and inhibit tumor growth in nude mice. Moreover, because of the controlled release of Mg ions and biocompatibility of polydopamine, the modified Mg alloy supported extracellular matrix mineralization, alkaline phosphatase activity, and bone-related gene expression in C3H10T1/2. Bone implantation model in rats verified that the modified Mg showed excellent osteointegration. These findings prove that the use of mussel-inspired multifunction film on Mg alloy offers a promising strategy for the therapy of primary malignant bone tumor.
