Label-free hairpin probe for the rapid detection of Hg(II) based on T-Hg(II)-T

Development of a split G-quadruplex and DAPI-based fluorescent probe for Hg(ii) and Pb(ii) ions detection

“…As expected, this conclusion is consistent with previous studies. 24 In comparing ODN-1 and ODN-4 (Fig. 1(b)), there was almost no change in response to Hg( ii ) by adding DAPI after incubating for 20 minutes.…”

“…As expected, this conclusion is consistent with previous studies. 24 In comparing ODN-1 and ODN-4 (Fig. 1 S1.…”

“…The probe utilizes that DAPI can recognize T-Hg(II)-T mismatched pairs with the assistance of GC base pairs, giving the uorescence intensity as strong as intercalated into TA base pairs. 24 Moreover, Pb(II) triggers a conformational switch in G-quadruplex structures, 34 which has been utilized in other strategies for Pb(II) detection. 35,36 Here, we hypothesized that the G-quadruplex could also control the intercalation of DAPI into the T-Hg(II)-T mismatches, allowing for Pb(II) detection using the same principle as for Hg(II).…”

“…These biosensors capitalize on forming a stable T–Hg( ii )–T structure, which exhibits more excellent stability than natural TA/AT base pairs. DNA molecules can form stable structures like a hairpin, double helix, and triplex, which can be recognized by some intercalated days, such as DAPI, 24,25 NMM, 26 ThT, 27 Genefinder, 28 SYBR Green I, 29 and Berberine. 30 Our previous study discovered that DAPI could effectively intercalate into the T–Hg( ii )–T mismatched base pairs, especially with CG base pairs.…”

“…The fluorescence intensity of DAPI intercalating into T–Hg( ii )–T mismatches was comparable to its intercalation into the more commonly studied TA/AT base pairs. 24 When Hg( ii ) is present, it facilitates the formation of T–Hg( ii )–T structures. This interaction creates a strong fluorescence signal when introducing DAPI, allowing for Hg( ii ) detection.…”