Exposure to high concentration of Hg2+ can cause irreversible damage to human tissues. Although a variety of sensors have been exploited for the detection of Hg2+, quantitatively monitoring heavy metal ions in vitro and in vivo remains a major challenge, because of cell-to-cell variations and background signal. We report here a Janus nanoparticle-DNA conjugate (JNP-DNA) as a novel probe that can quantify intracellular Hg2+ concentrations in living cells. JNPs were fabricated with half of the particle covered with gold and the other half loaded with fluorophores, serving as an internal standard. A DNA-based Hg2+ sensor featuring a thymine-rich sequence was attached to the gold half. In the presence of Hg2+, the fluorescence signal from DNA sensor increased accordingly while the internal control fluorescence signal remained unchanged. The JNP-DNA probes respond quantitatively and ratiometrically to Hg2+ in aqueous solution. Moreover, the JNP-DNA probes are demonstrated to be cell permeable and can be used to quantitatively monitor real-time Hg2+ uptake by cells.

Using Janus nanoparticle-DNA conjugates as ratiometric probes for quantitative detection of mercury ions in live cells

245th National Meeting (2013)

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