A novel β-Cyclodextrin-QDs optical biosensor for the determination of amantadine and its application in cell imaging

In this paper, a novel optical biosensor for amantadine (AD) determination has been constructed successfully based on the fluorescence resonance energy transfer (FRET) between water-soluble beta-Cyclodextrin (beta-CD)-functionalized CdTe quantum dots (QDs) and Rhodamine B (RB). RB could enter the cavity of beta-CD by hydrophobic interaction, and the process of FRET between QDs and RB occurred. However, the process of FRET was switched off with the addition of AD, due to its larger hydrophobic association constant with beta-CD than that of RB. The fluorescence intensity of CdTe QDs (donor) would increase gradually with the increasing concentration of AD, which shown a good linear relationship in the range of 1 x 10(-5)-1.6 x 10(-4) mol/L with a correlation coefficient R-2=0.998. We also obtained a satisfactory result using this spectrophotometric method for the determination of AD in pharmaceutical formulation. Furthermore, beta-CD-functionalized CdTe QDs with AD in the cavity were incubated with target HepG2 cells and could be observed in the cytoplasm of cells. The beta-CD-functionalized CdTe QDs could act as a visible biomarker for AD in cancer cells fluorescence imaging, which presents a potential application in biomedical field. (C) 2012 Elsevier B.V. All rights reserved.