I have used two wavelengths for MTT assay. so i want to ask which wavelentgth i have to take ? or average ? I have taken at 562 and 592 nm

hi

normally MTT should be read at 570nm or in between 550-600nm, i have read mine at 595nm before and compared to that in 570nm, they are all around more or less than 0.002 different in OD. You have to set up a standard curve for your experiment anyway, if you can't use the recommended wavelength (570nm), i would recommend you to choose one (either 562nm or 592nm) and stick with it.

You may take any one of them. But stick with one wavelength for whole study which would be much better for your analysis.

Dear Smriti,

In our studies toxicity evaluations were performed using two cytotoxicity assays instead of just one and ABSORBANCE WAS DETERMINED AT 540nm. This is because certain chemicals have been reported to give divergent results in different toxicity tests including the NRU and MTT assays (Olivier et al 1995; Chiba et al 1998). Besides, Evans et al (2001) have recently found that in some cases one of the NRU or MTT assays can be more sensitive in detecting the toxicity of non-viral transfection reagents.

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Evans, A.R., Alexander, D., Burke, P. and Reed, C.J. (2001) Toxicity and transfection efficiency: comparison between four commercially available non-viral transfection reagents in a human bronchial epithelial cell line. British Pharmaceutical Conference Science Proceedings 2001,  106.

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Evans, A. (2003) In Vitro and Ex Vivo Studies on the Toxicity and Efficacy of a Selection of Non-Viral Transfection Reagents.  PhD Thesis, Liverpool John Moores University, Liverpool, UK.

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Please also see attached paper.