

鈥淐ongo red鈥� is not the name of a famous African explorer, but a dye that dates to 1883. It was synthesized by P. B枚ttiger as a textile dye, but it subsequently became more important as a pH indicator. It colors aqueous solutions blue below pH 3.0 and becomes red above pH 5.0.
Recently, I. A. Buhimschi and co-workers at Nationwide Children鈥檚 Hospital (Columbus, OH) found a new use for Congo red. Taking a cue from Alzheimer鈥檚 disease researchers who found that the dye can be used to detect misfolded proteins, they showed that proteins in the urine of pregnant women who suffer from preeclampsia cause Congo red to change color. An Alzheimer鈥檚 researcher not involved in the study says, 鈥淭he diagnostic potential is really big鈥攄epending on how specific it turns out to be for preeclampsia.鈥�

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