A Label-Free and Sensitive Fluorescent Qualitative Assay for Bisphenol A Based on Rolling Circle Amplification/Exonuclease III-Combined Cascade Amplification.
Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-combined cascade amplification strategy. First, the duplex DNA probe (RP) with anti-BPA aptamer and trigger sequence was designed for BPA recognition and signal amplification. Next, under the action of BPA, the trigger probe was liberated from RP to initiate RCA reaction as primary amplification. Subsequently, the RCA products were used to trigger Exo III assisted secondary amplification with the help of hairpin probes, producing plenty of "G-quadruplex" in lantern-like structures. Finally, the continuously enriched "G-quadruplex lanterns" were lightened by zinc(II)-protoporphyrin IX (ZnPPIX) generating enhanced fluorescence signals. By integrating the primary RCA and secondary Exo III mediated cascade amplification strategy, this method displayed an excellent sensitivity with the detection limits of 5.4 × 10-17M. In addition, the anti-BPA aptamer exhibits high recognition ability with BPA, guaranteeing the specificity of detection. The reporter signal probe (G-quadruplex with ZnPPIX) provides a label-free fluorescence signals readout without complicated labeling procedures, making the method simple in design and cost-effective in operation. Moreover, environmental samples analysis was also performed, suggesting that our strategy was reliable and had a great potential application in environmental monitoring.
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. lixia@lcu.edu.cn.|School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China. lixia@lcu.edu.cn.
Xia
X
Li
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. songjuan19910321@163.com.
Juan
J
Song
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. xueqingwang1983@163.com.
Qing-Wang
QW
Xue
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. youfuheng1993@sina.com.
Fu-Heng
FH
You
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. luxia2401012932@163.com.
Xia
X
Lu
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. kongyancong1212@163.com.
Yan-Cong
YC
Kong
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. mashuyi1212@126.com.
Shu-Yi
SY
Ma
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China. wjiang@sdu.edu.cn.
Wei
W
Jiang
Department of Chemistry, Liao Cheng University, Liaocheng 252059, China. licz@fiu.edu.|Nanobioengineering/Bioelectronics Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA. licz@fiu.edu.
Chen-Zhong
CZ
Li
Exo III; bisphenol A; cascade amplification; label-free; rolling circle amplification