Analytical Sciences

Visual and On-site Detection of Mercury(II) Ions on Lateral Flow Strips Using DNA-functionalized Gold Nanoparticles

Fei YANG, Jing DUAN, Min LI, Zebo WANG, and Zhiyong GUO

Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, P. R. China

A test strip for detection of Hg²⁺ in aqueous solution based on the DNA-functionalized gold nanoparticles (DNA-AuNPs) was developed and evaluated. When Hg²⁺ ions were introduced, the biotinylated DNA₂ hybridized with thiolated DNA₁ functionalized on the AuNPs (DNA₁-AuNPs) to form mismatch complexes through thymine-Hg²⁺-thymine (T-Hg²⁺-T) coordination. The formed mismatch complexes and excess DNA₁-AuNPs could be captured on the test line formed by streptavidin and the control line formed by DNA₃-BSA, respectively. Two red lines appeared due to the accumulation of AuNPs, enabling visual detection of Hg²⁺ with a detection limit of about 6 nM. The assay results can be obtained within 5 min. The results show that the test strip has excellent sensitivity and selectivity for detection of Hg²⁺; thus it holds a great potential for rapid, on-site and real time detection of Hg²⁺.

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