A Highly Sensitive and Selective Competition Assay for the Detection of Cysteine Using Mercury-Specific DNA, Hg2+ and Sybr Green I

Sensors

Hui Xu¹  Shuli Gao¹  Quanwen Liu¹  Dun Pan²  Lihua Wang²  Shuzhen Ren³  Min Ding³  Jingwen Chen³ 

[1] School of Chemistry and Material Sciences, Ludong University, Yantai 264025, China; E-Mails:;Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; E-Mails:;Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, China; E-Mails:

关键词: cysteine;    competition assay;    mercury-specific DNA;    Hg²⁺;    Sybr Green I;   

DOI  :  10.3390/s111110187

来源: mdpi

【 摘 要 】

We here report a rapid, sensitive, selective and label-free fluorescence detection method for cysteine (Cys). The conformation of mercury-specific DNA (MSD) changes from a random coil form to a hairpin structure in the presence of Hg²⁺ due to the formation of a thymine-Hg²⁺-thymine (T-Hg²⁺-T) complex. Cys can selectively coordinate with Hg²⁺ and extract it from the thymine-Hg²⁺-thymine complex. The hairpin structure dehybridizes and the fluorescence intensity of Sybr Green I (SG) decreases upon addition of Cys because SG efficiently discriminates mercury-specific DNA and mercury-specific DNA/Hg²⁺ complex. The detection can be finished within 5 min with high sensitivity and selectivity. In addition, we can obtain variable dynamic ranges for Cys by changing the concentration of MSD/Hg²⁺.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.