title: Cytotoxicity studies of AZ31D alloy and the effects of carbon dioxide on its biodegradation behavior in vitro.
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.
authors.affiliation: Center for Translational Medicine Research and Development, Institute of Biomedical and Health Engineering, Chinese Academy of Sciences, Shenzhen 518055, China. wangjialicsu@yahoo.cn
authors.forename: Jiali
authors.initials: J
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Qin
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Ye
authors.initials: Y
authors.lastname: Yue
authors.forename: Yangde
authors.initials: Y
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Tang
authors.forename: Weirong
authors.initials: W
authors.lastname: Li
mesh_terms: D000497:Alloys / Q000494:pharmacology*; D000818:Animals; D001673:Biodegradation, Environmental / Q000187:drug effects; D001696:Biomechanical Phenomena / Q000187:drug effects; D002245:Carbon Dioxide / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003343:Corrosion; D017097:Electric Impedance; D004560:Electricity; D005269:Femur / Q000187:drug effects / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D006859:Hydrogen / Q000032:analysis; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology*; D008422:Materials Testing; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D011199:Potentiometry; D051381:Rats; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D002245:Carbon Dioxide; D006859:Hydrogen; D008274:Magnesium
keywords: Absorbable; Cytotoxicity; In vitro; Internal fixation; Magnesium and its alloys