In Vitro Corrosion and Biocompatibility of Coated MgCa1.0 Magnesium Alloys

2011 ◽  
Vol 690 ◽  
pp. 409-412
Author(s):  
Paul Rosemann ◽  
Susanne Bender ◽  
Andreas Heyn ◽  
Jürgen Schmidt
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Ph Value ◽  
Corrosion Behaviour ◽  
Dip Coating ◽  
Chemical Oxidation ◽  
Essential Elements ◽  
Noise Measurements

As bio-absorbable implant material the magnesium alloy Mg-1Ca is able to degrade in-vivo. The mechanical properties of this alloy are similar to those of human bone; both Mg and Ca are essential elements in human body. The main problem is the high corrosion rate of this alloy. Two coating systems based on plasma-chemical oxidation and an organic dip coating are applied onto MgCa1.0 magnesium alloy in order to slow down the corrosion rate. The corrosion behaviour of the coated alloys was investigated with electrochemical noise measurements. The influence of hydrogen evolution and increasing pH-value on the cytotoxicity was examined. The results of these investigations suggest that a combination of both coating systems leads to promising degradation properties.

In vitro and in vivo biocompatibility and corrosion behaviour of a bioabsorbable magnesium alloy coated with octacalcium phosphate and hydroxyapatite

2015 ◽  
Vol 11 ◽  
pp. 520-530 ◽  
Author(s):  
Sachiko Hiromoto ◽  
Motoki Inoue ◽  
Tetsushi Taguchi ◽  
Misao Yamane ◽  
Naofumi Ohtsu
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Octacalcium Phosphate

In vitro Lipolysis as a Tool for the Establishment of IVIVC for Lipid-Based Drug Delivery Systems

2019 ◽  
Vol 16 (8) ◽  
pp. 688-697
Author(s):  
Ravinder Verma ◽  
Deepak Kaushik
Keyword(s):  
Drug Delivery ◽  
Ph Value ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Rapid Screening ◽  
Resonance Spectroscopy ◽  
Fed State ◽  
In Vitro Lipolysis ◽  
Ph Stat

: In vitro lipolysis has emerged as a powerful tool in the development of in vitro in vivo correlation for Lipid-based Drug Delivery System (LbDDS). In vitro lipolysis possesses the ability to mimic the assimilation of LbDDS in the human biological system. The digestion medium for in vitro lipolysis commonly contains an aqueous buffer media, bile salts, phospholipids and sodium chloride. The concentrations of these compounds are defined by the physiological conditions prevailing in the fasted or fed state. The pH of the medium is monitored by a pH-sensitive electrode connected to a computercontrolled pH-stat device capable of maintaining a predefined pH value via titration with sodium hydroxide. Copenhagen, Monash and Jerusalem are used as different models for in vitro lipolysis studies. The most common approach used in evaluating the kinetics of lipolysis of emulsion-based encapsulation systems is the pH-stat titration technique. This is widely used in both the nutritional and the pharmacological research fields as a rapid screening tool. Analytical tools for the assessment of in vitro lipolysis include HPLC, GC, HPTLC, SEM, Cryo TEM, Electron paramagnetic resonance spectroscopy, Raman spectroscopy and Nanoparticle Tracking Analysis (NTA) for the characterization of the lipids and colloidal phases after digestion of lipids. Various researches have been carried out for the establishment of IVIVC by using in vitro lipolysis models. The current publication also presents an updated review of various researches in the field of in vitro lipolysis.

scholarly journals Assessment of Galvanostatic Anodic Polarization to Accelerate the Corrosion of the Bioresorbable Magnesium Alloy WE43

2021 ◽  
Vol 11 (5) ◽  
pp. 2128
Author(s):  
Nils Wegner ◽  
Frank Walther
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Dissolution Rate ◽  
Anodic Polarization ◽  
Technical Application ◽  
Efficient Manner ◽  
Corrosion Morphology ◽  
Application Range ◽  
Alloy We43

In the field of surgery, bioresorbable magnesium is considered a promising candidate. Its low corrosion resistance, which is disadvantageous for technical application, is advantageous for surgery since the implant fully degrades in the presence of the water-based body fluids, and after a defined time the regenerating bone takes over its function again. Therefore, knowledge of the corrosion behavior over several months is essential. For this reason, an in vitro short-time testing method is developed to accelerate the corrosion progress by galvanostatic anodic polarization without influencing the macroscopic corrosion morphology. The initial corrosion rate of the magnesium alloy WE43 is calculated by detection of the hydrogen volume produced in an immersion test. In a corresponding experimental setup, a galvanostatic anodic polarization is applied with a three-electrode system. The application range for the polarization is determined based on the corrosion current density from potentiodynamic polarization. To correlate the initial corrosion rate, and accelerated dissolution rate, the corrosion morphologies of both test strategies are characterized by microscopy images, as well as energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The results demonstrate that the dissolution rate can be increased in the order of decades with the limitation of a changed corrosion morphology with increasing polarization. With this approach, it is possible to characterize and exclude new unsuitable magnesium alloys in a time-efficient manner before they are used in subsequent preclinical studies.

Features of in vitro and in vivo behaviour of magnesium alloy WE43

2018 ◽  
Vol 215 ◽  
pp. 308-311 ◽  
Author(s):  
Elena Lukyanova ◽  
Natalia Anisimova ◽  
Natalia Martynenko ◽  
Mikhail Kiselevsky ◽  
Sergey Dobatkin ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Alloy We43

An Original Aspirin-Containing Carbonic Anhydrase 9 Inhibitor Overcomes Hypoxia-induced Drug Resistance to Enhance The Efficacy of Myocardial Protection

2021 ◽  
Author(s):  
Wen Zhou ◽  
Bin Zhang ◽  
Keyu Fan ◽  
Xiaojian Yin ◽  
Jinfeng Liu ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Carbonic Anhydrase ◽  
Myocardial Ischemia ◽  
Ph Value ◽  
Acquired Resistance ◽  
Vital Role ◽  
Carbonic Anhydrase 9 ◽  
Myocardial Hypoxia

Abstract Purpose Hypoxic microenvironment plays a vital role in myocardial ischemia injury, generally leading to the resistance of chemotherapeutic drugs. This induces an intriguing study on mechanism exploration and prodrug design to overcome the hypoxia induced drug resistance.Methods In this study, we hypothesized that the overexpression of carbonic anhydrase 9 (CAIX) in myocardial cells is closely related to the drug resistance. Herein, bioinformatics analysis, gene knockdown and overexpression assay certificated the correlation between CAIX overexpression and hypoxia. An original aspirin-containing CAIX inhibitor AcAs has been developed.Results Based on the downregulation of CAIX level, both in vitro and in vivo, AcAs can overcome the acquired resistance, and more effectively attenuate myocardial ischemia and hypoxia injury than that of aspirin. CAIX inhibitor is believed to recover the extracellular pH value so as to ensure the stable effect of aspirin.Conclusion Results indicate great potential of CAIX inhibitor for further application in myocardial hypoxia injury therapy.

Mechanical Properties and Microarchitecture of Nanoporous Hydroxyapatite Bioceramic Nanoparticle Coatings on Ti and TiN

2006 ◽  
Vol 975 ◽  
Author(s):  
Andrei Stanishevsky ◽  
Shafiul Chowdhury ◽  
Nathaniel Greenstein ◽  
Helene Yockell-Lelievre ◽  
Jari Koskinen
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Biological Response ◽  
Dip Coating ◽  
Nano Crystalline ◽  
Ceramic Manufacturing ◽  
Nanoparticle Coatings

ABSTRACTThe hydroxyapatite (HA) based bioceramic materials are usually prepared at high sintering temperatures to attain suitable mechanical properties. The sintering process usually results in a material which is compositionally and morphologically different from nonstoichiometric nano-crystalline HA phase of hard tissue. At the same time, HA particulates used as precursors in ceramic manufacturing are often very similar to the natural HA nanocrystals. It has been shown that synthetic nanoparticle HA (nanoHA) based materials improve the biological response in vitro and in vivo, but the information on mechanical properties of these materials is scarce.In this work we studied the HA nanoparticle (10 – 80 nm mean size) coatings with 30 – 70% porosity prepared by a dip-coating technique on Ti and TiN substrates. It has been found that the mechanical properties of HA nanoparticle coatings are strongly influenced by the initial size, morphology, and surface treatment of nanoparticles. The nanoindentation Young's modulus and hardness of as–deposited nanoHA coatings were in the range of 2.5 – 6.9 GPa and 80 – 230 MPa, respectively. The coatings were stable after annealing up to at least 600 °C, reaching the Young's modulus up to 23 GPa and hardness up to 540 MPa, as well as in simulated body fluids.

scholarly journals The Effect of Ca on In Vitro Behavior of Biodegradable Zn-Fe Alloy in Simulated Physiological Environments

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1624
Author(s):  
Orit Avior ◽  
Noa Ben Ghedalia-Peled ◽  
Tomer Ron ◽  
Razi Vago ◽  
Eli Aghion
Keyword(s):  
Corrosion Rate ◽  
Metabolic Activity ◽  
Electrochemical Analysis ◽  
Open Circuit ◽  
Hydrogen Gas ◽  
Hardness Tests ◽  
Fe Alloys ◽  
Cytotoxicity Assessment

The growing interest in Zn based alloys as structural materials for biodegradable implants is mainly attributed to the excellent biocompatibility of Zn and its important role in many physiological reactions. In addition, Zn based implants do not tend to produce hydrogen gas in in vivo conditions and hence do not promote the danger of gas embolism. However, Zn based implants can provoke encapsulation processes that, practically, may isolate the implant from its surrounding media, which limits its capability of performing as an acceptable biodegradable material. To overcome this problem, previous research carried out by the authors has paved the way for the development of Zn-Fe based alloys that have a relatively increased corrosion rate compared to pure Zn. The present study aims to evaluate the effect of 0.3–1.6% Ca on the in vitro behavior of Zn-Fe alloys and thus to further address the encapsulation problem. The in vitro assessment included immersion tests and electrochemical analysis in terms of open circuit potential, potentiodynamic polarization, and impedance spectroscopy in phosphate buffered saline (PBS) solution at 37 °C. The mechanical properties of the examined alloys were evaluated by tension and hardness tests while cytotoxicity properties were examined using indirect cell metabolic activity analysis. The obtained results indicated that Ca additions increased the corrosion rate of Zn-Fe alloys and in parallel increased their strength and hardness. This was mainly attributed to the formation of a Ca-rich phase in the form CaZn13. Cytotoxicity assessment showed that the cells’ metabolic activity on the tested alloys was adequate at over 90%, which was comparable to the cells’ metabolic activity on an inert reference alloy Ti-6Al-4V.

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