G-Quadruplex DNA for Fluorescent and Colorimetric Detection of Thallium(I)
Why this work is in the frame
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Bibliographic record
Abstract
Thallium is a highly toxic heavy metal, but its sensing is underexplored compared to its neighboring elements in the periodic table: lead and mercury. Thallium has two oxidation states. A DNAzyme-based biosensor for Tl 3+ was reported recently, representing the first work in this area. However, the most environmentally abundant thallium is monovalent Tl +, which is the focus of this work. Since Tl + is similar to K + in terms of size and charge, G-quadruplex DNAs are herein tested for Tl + detection. First, nine dual fluorophore labeled DNA probes are screened. Among them, a DNA designated PS2.M has the largest increase in fluorescence resonance energy transfer (FRET) efficiency upon Tl + addition. This FRET-based assay is directly used as a biosensor yielding a detection limit of 59 μM Tl + . In comparison, K + had a much lower response and the other tested monovalent metals do not produce a significant signal increase. In addition, a colorimetric sensor was developed based on DNA protected gold nanoparticles. When folded by Tl +, the nonlabeled PS2.M DNA cannot effectively adsorb onto gold nanoparticles. This leads to a color change from red to blue upon salt addition. The detection limit is 4.6 μM Tl +, and Tl + spiked in a lake water sample can also be detected. CD spectroscopy is used to further understand Tl + binding to PS2.M. This study demonstrates that DNA can also be used for detecting Tl +, and this work gives rise to a highly effective probe for this purpose.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it