abstract
MgCa and MgGd series of alloys are often reported as promising candidates for biomedical applications. In the present study, cytotoxicity and corrosion behavior of Mg1Ca and Mg10Gd alloys in different electrolytes (NaCl, PBS, MEM) have been investigated in order to make a direct comparison and understand the mechanisms behind their performance. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were employed to analyze corrosion processes depending on media composition, whereas X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to evaluate crystalline structure, phase composition and surface morphology of the corroded substrates after immersion in the different electrolytes. Moreover, cytotoxicity of the Mg alloys was assessed using the WST-1 reduction and lactate dehydrogenase (LDH) release assays in L929 mouse fibroblasts. The electrochemical results showed that Mg1Ca has a lower degradation rate when compared to Mg10Gd, due to the lower microgalvanic effects and the presence of Ca as an alloying element. Furthermore, the corrosion activity is reduced in MEM, for both alloys, when compared to NaCl and PBS. The cytotoxicity assays revealed that Mg10Gd was cytotoxic in all the conditions tested, while the toxicity of Mg1Ca was low. Overall, these findings show that Mg1Ca alloy presents a higher corrosion resistance and biocompatibility and is a promising material to be used in biomedical implants.
keywords
IN-VIVO CORROSION; MAGNESIUM ALLOYS; RARE-EARTH; MECHANICAL-PROPERTIES; DEGRADATION; VITRO; CYTOTOXICITY; BIODEGRADATION; BIOMATERIALS; PERFORMANCE
subject category
Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering
authors
Neves, CS; Sousa, I; Freitas, MA; Moreira, L; Costa, C; Teixeira, JP; Fraga, S; Pinto, E; Almeida, A; Scharnagl, N; Zheludkevich, ML; Ferreira, MGS; Tedim, J
our authors
Cristina Sofia dos Santos Neves
Junior Researcher
Isabel Cristina de Sá Correia de Sousa
Junior Researcher
João Tedim
Associate Professor
Mário Guerreiro Silva Ferreira
Retired Professor
Mikhail Zheludkevich
Invited Principal Researcheracknowledgements
This work was financed by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of Operational Competitiveness and Internationalization Programme (POCI), in the scope of the project MAGICOAT POCI-01-0145-FEDER-016597/PTDC/CTM-BIO/2170/2014 and in the scope of the project CICECO -Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. Furthermore, thanks are due to Portuguese Foundation for Science and Technology/MCTES for the financial support through national funds to EPI Unit (UIDB/04750/2020).