Exonuclease III-assisted graphene oxide amplified fluorescence anisotropy strategy for ricin detection.
Graphene oxide (GO) is an excellent fluorescence anisotropy (FA) amplifier. However, in the conventional GO amplified FA strategy, one target can only induce the FA change of one fluorophore on probe, which limits the detection sensitivity. Herein, we developed an exonuclease III (Exo III) aided GO amplified FA strategy by using aptamer as an recognition element and ricin B-chain as a proof-of-concept target. The aptamer was hybridized with a blocker sequence and linked onto the surface of magnetic beads (MBs). Upon the addition of ricin B-chain, blocker was released from the surface of MBs and hybridized with the dye-modified probe DNA on the surface of GO through the toehold-mediated strand exchange reaction. The formed blocker-probe DNA duplex triggered the Exo III-assisted cyclic signal amplification by repeating the hybridization and digestion of probe DNA, liberating the fluorophore with several nucleotides (low FA value). Thus, ricin B-chain could be sensitively detected by the significantly decreased FA. The linear range was from 1.0μg/mL to 13.3μg/mL and the limit of detection (LOD) was 400ng/mL. This method improved the sensitivity of FA assay and it could be generalized to any kind of target detection based on the use of an appropriate aptamer.
Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing, PR China.
Xue
X
Xiao
Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing, PR China.
Jing
J
Tao
College of Pharmaceutical Sciences, Southwest University, 400715 Chongqing, PR China.
Hong Zhi
HZ
Zhang
Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing, PR China; College of Pharmaceutical Sciences, Southwest University, 400715 Chongqing, PR China. Electronic address: chengzhi@swu.edu.cn.
Cheng Zhi
CZ
Huang
Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, 400715 Chongqing, PR China. Electronic address: zsj@swu.edu.cn.
Shu Jun
SJ
Zhen
D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002619:Chemical Warfare Agents / Q000032:analysis*; D015342:DNA Probes / Q000737:chemistry; D005090:Exodeoxyribonucleases / Q000737:chemistry; D005454:Fluorescence Polarization / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D000067030:Fruit and Vegetable Juices / Q000032:analysis; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D010087:Oxides / Q000737:chemistry; D012276:Ricin / Q000032:analysis*
D052157:Aptamers, Nucleotide; D002619:Chemical Warfare Agents; D015342:DNA Probes; D005456:Fluorescent Dyes; D010087:Oxides; D006108:Graphite; D012276:Ricin; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III
Exonuclease III; Fluorescence anisotropy; Ricin B-chain