Ammonia-containing dimethyl sulfoxide: An improved solvent for the dissolution of formazan crystals in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay

To reduce interference with the dissolution of formazan crystals in the 3-(4,5-dimethylthiazo1-2-yl)-2,5-diphenyl tetrazolium bromide (MU) assay, we conducted a systematic investigation to study the effects of various buffers, HCl, NaOH. and ammonia. As a result, we identified an improved solvent, alkaline dimethyl sulfoxide (DMSO) containing 8 to 800 mM ammonia, which could dissolve formazan crystals in approximately 10 min so as to give a stable spectrum by eliminating buffering effects of the residual medium. (C) 2011 Elsevier Inc. All rights reserved.