[Show abstract][Hide abstract] ABSTRACT: Magnesium alloys have been advocated as potential artificial bone materials due to their biocompatibility and biodegradability. The understanding of their corrosive mechanism in physiological environments is therefore essential for making application-orientated designs. Thus, this in vitro study was designed to assess the effects of CO2 on corrosive behavior of AZ31D to mimic in vivo special ingredient. Electrochemical technologies accompanied with Scanning electron microscope, Fourier transform infrared, X-ray diffraction, Energy dispersive spectroscopy and hydrogen evolution measurement were employed to analyze corrosive rates and mechanisms of AZ31D. Moreover, the biocompatibility of AZ31D was assessed with a direct cell attachment assay and an indirect cytotoxicity test in different diluted extracts. The ion concentrations in extracts were measured using inductively coupled plasma mass spectrometry to offer explanations on the differences of cell viability in the indirect test. The results of the direct cytotoxicity assay showed that the corrosive rate of AZ31D was too rapid to allow for cell adhesion. Extracts diluted less than 20 times would cause adverse effects on cell proliferation, likely due to excessive ions and gas release. Moreover, the presence of CO2 did not cause significant differences on corrosive behavior of AZ31D according to the results of electrochemical testing and hydrogen evolution measurement. This might be caused by the simultaneous process of precipitation and dissolution of MgCO3 due to the penetration role of CO2. This analysis of corrosive atmospheres on the degradation behavior of magnesium alloys would contribute to the design of more scientific in vitro testing systems in the future.
[Show abstract][Hide abstract] ABSTRACT: Magnesium (Mg) or its alloys have shown great potential as promising biocorrosive or biodegradable implantation materials and/or internal fixators, owing to their good biocompatibility and osteoinductive potential. However, poor anticorrosion property or rapid biodegradation has limited their clinical applications where initial mechanical stabilisation is required. One of the practical approaches for decreasing its biodegradation is to introduce a coating on Mg or its alloys. The current study compared the two most widely used coating techniques, i.e., microarc oxidation (MAO) and electrophoresis deposition (EPD), for coating onto the Mg–Zr pin surface, both in vitro and in vivo, to determine which method can prevent Mg–Zr alloy degradation better. In vitro pH measurement and in vivo microcomputed tomographic evaluation were used for determining its degradation rate. Our in vitro and in vivo testing results indicated that EPD demonstrated better corrosion resistance than MAO, implying the potential of electrochemical technology for surface modification of Mg or its alloys developed for orthopaedic applications.
Journal of Orthopaedic Translation. 01/2013; 1(1):41–48.
[Show abstract][Hide abstract] ABSTRACT: As a bioabsorbable metal with mechanical properties close to bone, pure magnesium or its alloys have great potential to be developed as medical implants for clinical applications. However, great efforts should be made to avoid its fast degradation in vivo for orthopedic applications when used for fracture fixation. Therefore, how to decease degradation rate of pure magnesium or its alloys is one of the focuses in Research and Development (R&D) of medical implants. It has been recognized that surface modification is an effective method to prevent its initial degradation in vivo to maintain its desired mechanical strength. This article reviews the recent progress in surface modifications for prevention of fast degradation of magnesium or its alloys using in vitro testing model, a fast yet relevant model before moving towards time-consuming and expensive in vivo testing. Pros and cons of various surface modifications are also discussed for the goal to design available products to be applied in clinical trials.
Journal of Biomedical Materials Research Part B Applied Biomaterials 05/2012; 100(6):1691-701. · 2.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: New drug exploration is difficult in a clinical setting and the development of new drugs may be costly and time consuming. With further research into the pathological mechanisms and etiology of diseases as well as the rapid development of biological techniques, many 'old drugs' that have been applied in clinics may have new therapeutic functions which may shed light on clinical management. Based on this, we have investigated the 'old drugs for new applications' strategy in pharmacology which may be less expensive and more efficient in the clinical setting. In this paper we have explored and illustrated the potential applications of 'old drugs' for the treatment of orthopedic diseases, especially in arthritis and osteoporosis therapy.
Therapeutic advances in musculoskeletal disease 08/2011; 3(4):201-5.