Fluorescence Reporting Based on FRET Between Conjugated Polyelectrolyte and Organic Dye for Biosensor Applications - Advanced Fluorescence Reporters in Chemistry and Biology - page 425

3.5

3

2.5

2

1.5

1

0.5

0

400 450 500

Wavelength, nm

550 600 650

Fig. 2 PL spectra of 1I with complementary ssDNA 3 -F1/ssDNA 4 ( red ) and noncomplementary
ssDNA 3 -F1/ssDNA 5 ( black ) in saline-sodium citrate buffer. The spectra were normalized to the
polymer emission [ 50 ]

Compl. vs Nocompl.

C

C

Scheme 5 Schematic illustration of the working mechanism of CCP/intercalating dye/DNA
sensor

To overcome the nonspecific interactions between ssDNA-C* and CCP, Fan
et al. introduced a magnetic microparticle assisted assay [ 54 ], which allows DNA
detection in human serum with 0.1 nM sensitivity. In addition, DNA intercalating
dyes were introduced for DNA detection as shown in Scheme 5 . These special dyes
have much higher fluorescence quantum yields upon intercalation with dsDNA
relative to those in the presence of ssDNA or in their free states. As a result, when
complementary ssDNA strands (target and probe) are present, the intercalating dye