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Colorimetric Detection of Hg 2+ Based on the Growth of Aptamer‐Coated AuNPs: The Effect of Prolonging Aptamer Strands
Author(s) -
Tan Lulu,
Chen Zhengbo,
Zhang Chi,
Wei Xiangcong,
Lou Tianhong,
Zhao Yan
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201603370
Subject(s) - aptamer , detection limit , colloidal gold , adsorption , desorption , chemistry , selectivity , nanoparticle , nanotechnology , combinatorial chemistry , analytical chemistry (journal) , chromatography , materials science , organic chemistry , biology , microbiology and biotechnology , catalysis
Herein, a versatile and sensitive colorimetric sensor for Hg 2+ based on aptamer–target specific binding and target‐mediated growth of AuNPs is reported. The 15 T bases are first designed to detect Hg 2+ through T–Hg 2+ –T coordination. Aptamer–target binding results in the desorption of the aptamer from AuNP surface, the remaining aptamers adsorbed on AuNP surface trigger the growth of AuNPs with morphologically varied nanostructures, and then different colored solutions are formed. On this occasion, the limit of detection (LOD) of 9.6 × 10 −9 m is obtained. The other two aptamer strands (25‐ and 59‐mer) are designed by increasing A bases on either side and both sides of 15 T, respectively. The interaction of the binding domain and Hg 2+ makes desorption of 15 T from AuNP surface, whereas excess bases not committed to the binding domain still adsorbed on AuNP surface. These excess bases control the growth of AuNPs, and enhance the sensitivity. The LODs are 4.05 and 3 × 10 −9 m for 25‐ and 59‐mer aptamers, respectively. In addition, the 59‐mer aptamer system is applied to identify Hg 2+ in real river samples, the LOD of 6.2 × 10 −9 m is obtained.