Employing aqueous CdTe quantum dots with diversified surface functionalities to discriminate between heme (Fe(II)) and hemin (Fe(III)).

The discrimination of ferrous and ferric states in the human body is one of the basic issues for disease control and prevention because Fe(II) and Fe(III) are a crucial redox pair during the process of material and energy metabolism. Herein, aqueous CdTe quantum dots (QDs) with diversified surface functionalities are applied to discriminate between heme (Fe(II)) and hemin (Fe(III)) by virtue of their difference in quenching QD fluorescence. In aqueous media, the interaction between QDs and heme/hemin mainly involves electrostatic interaction, which is greatly determined by the surface functionalities of the QDs. Thus, by combining the different fluorescence quenching behavior of carboxyl- and/or hydroxyl-functionalized QDs, heme and hemin are discriminated between. In comparison to the discrimination using QDs with single surface functionality, the current method has improved reliability and accuracy.