Interference of magnesium corrosion with tetrazolium-based cytotoxicity assays☆

Abstract

Magnesium (Mg) alloys are promising materials for the development of biodegradable implants. However, the current in vitro test procedures for cytotoxicity, cell viability and proliferation are not always suitable for this class of materials. In this paper we show that tetrazolium-salt-based assays, which are widely used in practice, are influenced by the corrosion products of Mg-based alloys. Corroded Mg converts tetrazolium salts to formazan, leading to a higher background and falsifying the results of cell viability. Tetrazolium-based assays are therefore not a useful tool for testing the cytotoxicity of Mg in static in vitro assays.

Porous magnesium-based scaffolds for tissue engineering

“…Therefore, using these assays should be conducted with high level of caution. It is suggested [100] to use luminescence-based (BrdU) cytotoxicity assays which do not have any interference with the corroding magnesium. cell proliferation and cell cycle progression [101][102][103][104].…”

Biodegradation of a magnesium alloy implant in the intercondylar femoral notch showed an appropriate response to the synovial membrane in a rabbit model in vivo

“…Immediately before the test, the extracts were replaced with cell culture medium because tetrazolium salts interfere with magnesium. 23 The extracts were incubated with the MTS salts for 2-3 h. The soluble formazan product was quantified by measuring the absorbance using a mQuant Microplate Spectrophotometer (BioTek Instruments, Bad Friedrichshall, Germany) at a wavelength of 490 nm (reference wavelength 650 nm). In accordance with DIN EN ISO 10993-5, relative metabolic activity below 70% was regarded as cytotoxic.…”

Evaluation of the Ability of Malassezia Species in Biofilm Formation

“…A vital MTT dye could be used for this purpose. The MTT test is a semi-quantitative colorimetric method to measure cell viability (23,24). This method was used in the current study.…”