Conjugates, Complexes, and Interlocked Systems Based on Squaraines and Cyanines - Advanced Fluorescence Reporters in Chemistry and Biology - page 181

(CH 2 ) 3 SO 3 H

N

N

DIR

RNA Aptamer

Fluoromodule

Fig. 12 Synthesis of the DIR-RNA-aptamer fluoromodule

intense absorbance in the red region of the visible spectrum with l max Ab ¼ 602 nm

134,000 M 1 cm 1 in methanol. The dye fluorescence is very low in
aqueous buffer but increases about 80-fold in a solution of 90% glycerol in water. In
the presence of double-stranded DNA, the fluorescence of DIR increases only
twofold. Binding to a specific RNA-aptamer strongly enhances DIR fluorescence,
whereas nonspecific RNA has no effect on the dye fluorescence. The developed
DIR-RNA-aptamer fluoromodule was proposed to have applications as a signaling
component for sensors. This approach is suggested to be used to design new
dye-aptamer complexes with improved properties.

and e M ¼

COOH HOOC

HOOC

COOH

COOH

HOOC

HOOC COOH

HOOC COOH

COOH

HOOC

HOOC

COOH

Polyphenylene dendrimer COOH HOOC

Dye-aptamer complexes can be used also to develop high specific and selective
colorimetric chemosensors. For example, the displacement of the heptamethine dye 26b