Thioflavin T behaves as an efficient fluorescent ligand for label-free ATP aptasensor.
Here, we for the first time demonstrated thioflavin T (ThT) as an efficient fluorescent ligand for 27-mer ATP-binding aptamer (ABA27), providing a novel signal readout mode for label-free selective ATP detection. ABA27 can promote the fluorescence emission of ThT with an unprecedentedly high efficiency, attributed to the specific structure of ABA27 rather than the G-tracts. Polyacrylamide gel electrophoresis, fluorescence spectroscopy, and fluorometric titration reveal that ThT interacts with ABA27 with a lower binding affinity (Kd ~89 μM) than ATP, which allows ATP to easily compete with ThT for the DNA binder. In the presence of ThT, adding ATP induces ABA27 to undergo a structural change, thereby not favoring the binding to ThT, verified by circular dichroism and UV-Vis absorption spectroscopy. As a result, the fluorescence intensity of ThT decreases dramatically, enabling the sensitive detection of ATP with high selectivity over other analogs. Such a sensing strategy may make ThT able to serve as a facile signal reporter for DNA nanomechanical devices fueled with ATP. Graphical Abstract The principle of the displacement of ThT by ATP.
Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui, 230026, China.
Huihui
H
Wang
Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui, 230026, China.
Pai
P
Peng
Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui, 230026, China.
Shuangna
S
Liu
Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Jinzhai Road 96, Hefei, Anhui, 230026, China. tlitao@ustc.edu.cn.
Tao
http://orcid.org/0000-0002-9724-3812
T
Li
D000255:Adenosine Triphosphate / Q000032:analysis*; D052157:Aptamers, Nucleotide / Q000737:chemistry; D052160:Benzothiazoles; D015374:Biosensing Techniques / Q000379:methods*; D002942:Circular Dichroism; D005456:Fluorescent Dyes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013844:Thiazoles / Q000737:chemistry*
D052157:Aptamers, Nucleotide; D052160:Benzothiazoles; D005456:Fluorescent Dyes; D013844:Thiazoles; C009462:thioflavin T; D000255:Adenosine Triphosphate
ATP; ATP aptasensor; Fluorescent ligand; ThT