Recent advances on the development of magnesium alloys for biodegradable implants.

http://nt13.aalto.fi/abstracts/posters/13012Abstract00283.pdf

Purification of carbon nanotubes

To evaluate the ability of Mg-6Zn to replace titanium nails in the reconstruction of the intestinal tract in general surgery, we compared the Mg-6Zn and titanium implants with respect to their effects on rat's intestinal tract by biochemical, radiological, pathological and immunohistochemical methods. The results indicated that Mg-6Zn implants started to degrade at the third week and disintegrate at the fourth week. No bubbles appeared, which may be associated with intestinal absorption of the Mg-6Zn implants. Pathological analyses (containing liver, kidney and cecum tissues) and biochemical measurements, including serum magnesium, creatinine, blood urea nitrogen, glutamic-pyruvic-transaminase and glutamic-oxaloacetic-transaminase proved that degradation of Mg-6Zn did not harm the important organs, which is an improvement over titanium implants. Immunohistochemical results showed that Mg-6Zn could enhance the expression of transforming growth factor-β1. Mg-6Zn reduced the expression of tumor necrosis factor at different stages. In general, our study demonstrates that the Mg-6Zn alloy had good biocompatibility in vivo and performed better than titanium at promoting healing and reducing inflammation. It may be a promising candidate for stapler pins in intestinal reconstruction.

Comparison of the effects of Mg-6Zn and titanium on intestinal tract in vivo.

Magnesium (Mg) based alloys have been extensively considered for their use as biodegradable implant materials. However, controlling their corrosion rate in the physiological environment of the human body is still a significant challenge. One of the most effective approaches to address this challenge is to carefully select alloying compositions with enhanced corrosion resistance and mechanical properties when designing the Mg alloys. This paper comprehensively reviews research progress on the development of Mg alloys as biodegradable implant materials, highlighting the effects of alloying elements including aluminum (Al), calcium (Ca), lithium (Li), manganese (Mn), zinc (Zn), zirconium (Zr), strontium (Sr) and rare earth elements (REEs) on the corrosion resistance and biocompatibility of Mg alloys, from the viewpoint of the design and utilization of Mg biomaterials. The REEs covered in this review include cerium (Ce), erbium (Er), lanthanum (La), gadolinium (Gd), neodymium (Nd) and yttrium (Y). The effects of alloying elements on the microstructure, corrosion behavior and biocompatibility of Mg alloys have been critically summarized based on specific aspects of the physiological environment, namely the electrochemical effect and the biological behavior.

Effects of alloying elements on the corrosion behavior and biocompatibility of biodegradable magnesium alloys: a review

To evaluate the different effects of Mg-6Zn alloy and Ti-3Al-2.5V alloy implants in intestinal tract healing, we compared these two different alloys with respect to their effect on a rat's intestinal tract, using serum magnesium, radiology, pathology and immunohistochemistry in vivo. It was found using the scanning electron microscope that the Mg-6Zn alloy began to degrade during the first week and that the Ti-3Al-2.5V alloy was non-degradable throughout the process. The Mg-6Zn alloy did not have an impact on serum magnesium. Superior to the Ti-3Al-2.5V alloy, the Mg-6Zn alloy enhanced the expression of transforming growth factor-β1 in healing tissue, and promoted the expression of both the vascular endothelial growth factor and the basic fibroblast growth factor, which helped angiogenesis and healing. The Mg-6Zn alloy reduced the expression of the tumor necrosis factor (TNF-α) at different stages and decreased inflammatory response, which may have been related to the zinc inhibiting TNF-α. In general, the Mg-6Zn alloy performed better than Ti-3Al-2.5V at promoting healing and reducing inflammation. The Mg-6Zn alloy may be a promising candidate for use in the pins of circular staplers for gastrointestinal reconstruction in medicine.

http://iopscience.iop.org/article/10.1088/1748-6041/9/2/025011/pdf

Comparison of the effects of Mg-6Zn and Ti-3Al-2.5V alloys on TGF-β/TNF-α/VEGF/b-FGF in the healing of the intestinal tract in vivo.

Non-destructive purification of multi-walled carbon nanotubes produced by catalyzed CVD

Effects of Sr and Sn on microstructure and corrosion resistance of Mg–Zr–Ca magnesium alloy for biomedical applications

Enhancement of the bioactivity of titanium oxide nanotubes by precalcification

TiO2 coating was obtained by sol–gel method to improve the corrosion resistance of Mg–Ca alloy in human body environment. The corrosion behavior of Mg–1.0 Ca alloy with TiO2 coating was investigated by electrochemical tests and immersion tests in simulated body fluid (SBF). Bare Mg–1.0 Ca alloy suffered serious attack after immersed in simulated body fluid only for 48 h. While for the Mg–1.0 Ca alloy with TiO2 coating, the surface almost maintained intact with only several collapses after immersed in SBF for 168 h. The electrochemical test results showed that the free corrosion current (i
 corr) of Mg–1.0 Ca alloy substrate was 3.3275e−2A/cm2, while the i
 corr of TiO2 coating was only 1.58549e−5A/cm2. Therefore, TiO2 coating significantly improved the corrosion resistance of Mg–1.0 Ca alloy in SBF. This enhances the potential of Mg–Ca alloy used as biodegradable orthopedic material.

Corrosion behavior in SBF for titania coatings on Mg–Ca alloy

Iron-based nanoscale coordination polymers synergistically induce immunogenic ferroptosis by blocking dihydrofolate reductase for cancer immunotherapy.

Qian Chen

Papers

Non-destructive purification of multi-walled carbon nanotubes produced by catalyzed CVD

Effects of Sr and Sn on microstructure and corrosion resistance of Mg–Zr–Ca magnesium alloy for biomedical applications

Enhancement of the bioactivity of titanium oxide nanotubes by precalcification

Corrosion behavior in SBF for titania coatings on Mg–Ca alloy

Iron-based nanoscale coordination polymers synergistically induce immunogenic ferroptosis by blocking dihydrofolate reductase for cancer immunotherapy.