Benoit Dubertret, Michel Calame, and Albert J. Libchaber

Nat. Biotechnol. 19, 365–370 (2001).

Because of a printing error, Figures 3 and 4 on pages 368 and 369 were printed incorrectly. The corrected figures are printed below. We regret the error.

Figure 3. Efficiency of the quenching of gold nanoparticles. The emission spectrum of hairpin DNA coupled to gold and to (A) fluorescein, (B) rhodamine 6G, (C) Texas red, and (D) Cy5. For each spectrum, we distinguish three steps: (1) the cuvet is filled with buffer; (2) the dye–DNA–gold conjugates are introduced in the cuvet; (3) a 10-fold excess of target 1 is added. The transition between each regime is marked with an arrow. The oligonucleotide concentrations are 3 nM for fluorescein, 1.5 nM for Cy5, 3 nM for rhodamine 6G, and 5 nM for Texas red. The concentrations of gold present in each cuvet are 0.5 μM for fluorescein, 0.4 μM for Cy5, 0.5 μM for rhodamine 6G, and 1 μM for Texas red. The precise values of the fluorescence intensities for each dye and for each regime are reported in Table 1.
Figure 4. Comparison of single-mismatch detection with gold-quenched beacons versus DABCYL-quenched beacons. Titration of 5 μM of random target mixed with 4.2 nM of gold–DNA–rhodamine 6G conjugate and 0.6 μM of gold (A), and 5 μM of random target mixed with 10 nM of molecular beacon (B), with the perfect target (target 2) and the mismatch one (target 3). Target concentrations vary from 67 pM to 13 μM. For both probes, the perfect target (solid line) produces a faster and sharper increase of fluorescence than the target containing the mismatch (dashed line). Fluorescence intensities due to the buffer and the gold have been subtracted. The inset graphs in (A) and (B) show the evolution of the fluorescence as a function of time when the probe is mixed with 5 μM of random targets. In both cases, the random targets do not induce any change of fluorescence of the probe during the time of the titration. The hybridization is thus very specific to the matched or the mismatched targets. (C) Ratio between the titration curve with the perfect target (target 2) and the titration curve with the mismatched one (target 3). (D) Resolution of a matched and a mismatched target, competing for hybridization. Molecular beacon (dashed line), gold–DNA–dye conjugate (solid line). α is the population ratio of match to mismatch targets. The concentration of perfect target is fixed at 0.2 μM.