Abstract
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+.
