Luminescent CdSe-ZnS quantum dots as selective Cu2+ probe

Luminescent CdSe-ZnS quantum dots (QDs) were modified with bovine serum albumin (BSA) and used as selective copper ion probe. The fluorescence of the water-soluble QDs can be quenched only by Cu2+ and Fe3+ in physiological buffer solution. Approximate concentrations of other physiologically important cations, such as Zn2+, Na+ and K+ etc. have no effect on the fluorescence. Adding F- to form the colorless complex FeF63- can eliminate the interference of Fe3+. The detection limit Of Cu2+ ions was 10 nM. The results can be explained in terms of strong binding of Cu2+ onto the surface of CdSe resulting in a chemical displacement of Cd2+ ions and the formation of CuSe on the surface of the QDs. (C) 2004 Elsevier B.V. All rights reserved.