Fluorescence Reporting Based on FRET Between Conjugated Polyelectrolyte and Organic Dye for Biosensor Applications - Advanced Fluorescence Reporters in Chemistry and Biology - page 440

350

Goat IgG
BSA
Thrombin

300

250

200

150

100

50

0

540 560 580 600 620 640

Wavelength (nm)

Fig. 9 PL spectra of the NP suspension in the presence of 10 (8 M) for antigoat IgG-NPs

m

(0.2 mg) incubated with various proteins (1 g/mL) and subsequent treatment with antigoat

m

IgG-Cy3 (0.18 mg/mL), excitation at 370 nm

compared to that upon direct excitation of Cy3 in the absence of 10, as a result of
efficient FRET. This study highlights that utilization of CPE as the energy donor
can impart signal amplification and eliminate cross-talking fluorescence for protein
immunoassays, which provides an opportunity to minimize the experimental errors
and to improve the detection sensitivity.

3.2 Aptamer-Based Sensor

The specific aptamer-protein interaction has recently been used for protein detec-
tion with high selectivity [ 99 ]. Aptamers are artificial nucleic acids selected in vitro
with high affinity to proteins and other biological compounds. In comparison with
traditional specific antibody-antigen recognition, the application of aptamer as the
probe has several advantages, which include easy preparation, stability, reusability
and general availability for almost any protein. Recently, we reported a strategy for
lysozyme detection that took advantage of specific aptamer/protein interaction and
aptamer/protein complexation mediated FRET between an ACP and a dye-labeled
aptamer [ 100 ]. The working mechanism for the assay is displayed in Scheme 11 ,
which involves poly[9,9-bis(4 0 -sulfonatobutyl)fluorene- co -alt-1,4-phenylene] sodium
salt (5) and a 6-carboxylfluorescein (FAM) labeled lysozyme aptamer as the energy
donor and acceptor, respectively. ACP 5 was chosen as the light-harvesting
molecule because of its high quantum yield in water (

0.9 in water) and