3 research outputs found
An in vitro mechanism study on the proliferation and pluripotency of human embryonic stems cells in response to magnesium degradation.
Magnesium (Mg) is a promising biodegradable metallic material for applications in cellular/tissue engineering and biomedical implants/devices. To advance clinical translation of Mg-based biomaterials, we investigated the effects and mechanisms of Mg degradation on the proliferation and pluripotency of human embryonic stem cells (hESCs). We used hESCs as the in vitro model system to study cellular responses to Mg degradation because they are sensitive to toxicants and capable of differentiating into any cell types of interest for regenerative medicine. In a previous study when hESCs were cultured in vitro with either polished metallic Mg (99.9% purity) or pre-degraded Mg, cell death was observed within the first 30 hours of culture. Excess Mg ions and hydroxide ions induced by Mg degradation may have been the causes for the observed cell death; hence, their respective effects on hESCs were investigated for the first time to reveal the potential mechanisms. For this purpose, the mTeSR®1 hESC culture media was either modified to an alkaline pH of 8.1 or supplemented with 0.4-40 mM of Mg ions. We showed that the initial increase of media pH to 8.1 had no adverse effect on hESC proliferation. At all tested Mg ion dosages, the hESCs grew to confluency and retained pluripotency as indicated by the expression of OCT4, SSEA3, and SOX2. When the supplemental Mg ion dosages increased to greater than 10 mM, however, hESC colony morphology changed and cell counts decreased. These results suggest that Mg-based implants or scaffolds are promising in combination with hESCs for regenerative medicine applications, providing their degradation rate is moderate. Additionally, the hESC culture system could serve as a standard model for cytocompatibility studies of Mg in vitro, and an identified 10 mM critical dosage of Mg ions could serve as a design guideline for safe degradation of Mg-based implants/scaffolds
Recommended from our members
Bio-Resorbable Magnesium-Based Biomaterials for Neural and Orthopedic Applications
Magnesium (Mg)-based biomaterials have attracted increasing attention in biomedical applications, such as neural and orthopedic applications because of the biocompatibility, biodegradability, antibacterial properties, and excellent mechanical properties. However, rapid degradation of Mg is the major concern for many clinical applications. To address the challenge, the present dissertation developed the two approaches, including engineering proper surfaces and alloying Mg with other elements to control the degradation of Mg-based biomaterials and enhance the overall performances of Mg for neural and orthopedic applications. The first part of the dissertation developed a method to deposit a conductive polymer coating, poly(3,4-ethylenedioxythiophene) (PEDOT) onto the surface of Mg microwire for potential neural recording and stimulation applications. The optimized parameters were found for the first time. It was found that the corrosion rate of PEDOT-coated Mg microwire was much slower than the non-coated Mg microwire. The second part of the research reported the fabrication, characterization, degradation and electrical properties of biodegradable magnesium (Mg) microwires coated with two functional polymers, and the first in vivo evidence on the feasibility of Mg-based biodegradable microelectrodes for neural recording. The third part of the dissertation developed biocompatible, biodegradable Magnesium-zinc-calcium (Mg–Zn–Ca) alloys with similar mechanical properties to human bone for orthopedic applications. The objectives were to characterize Mg–2wt.% Zn–0.5 wt.% Ca (named ZC21) alloy pins microstructurally and mechanically, and determine their degradation and interactions with host cells and pathogenic bacteria in vitro and in vivo. Overall, the entire dissertation provided extensive knowledge regarding engineering proper surfaces and alloying Mg with other elements towards desired performances for neural and orthopedic applications
Biocompatible magnesium alloys for hard tissue engineering
Novel Mg-Zr-Sr and Mg-1Zr-2Sr-xDy/yHo alloys have recently been developed for use as biodegradable implant materials. These alloys are recommended to be promising biodegradable implant materials as they have enhanced corrosion resistance and excellent biocompatibility