Steady-State and Time-Resolved Spectroscopic Study of [Ru(phen) <sub>2</sub> (dpqa)] <sup>2+</sup> Showing Enantiomer-Dependent DNA Light-Switch Behavior in Solution and in Live Cells
Bibliographic record
Abstract
Ruthenium polypyridyl complexes are becoming increasingly important as probes for cellular investigations due to their luminescent properties and the possibility of exploiting the interaction with biomolecules due to the differing chirality of their enantiomers. In this study, a DNA light-switch metal complex comprising an intercalating polypyridyl ligand with an amide-linked pentyl chain [Ru(phen) 2 (dpqa)] 2+ ( 1 ) (dpqa = 2-pentylamidodipyrido[3,2- f:2′,3′- h ]-quinoxaline) that undergoes cell internalization is reported. The photophysical properties are dramatically impacted by the amide linker such that 1 is nonluminescent in aqueous media but strongly luminescent when bound to natural DNA. Transient visible absorption and time-resolved infrared measurements show that this is caused by the emissive MLCT excited state being rapidly deactivated in water (11 ps) to another nonemissive excited state with a characteristic infrared spectrum. In the presence of DNA, the delta enantiomer is about 9 times more emissive than the lambda. 1 is internalized by live HeLa cells, and luminescence is observed in hydrophobic pockets. In the presence of the polysorbate 80 nonionic surfactant (Tween 80), which is expected to permeabilize the cell and nuclear membranes, a strong enantiomer-dependent signal was seen from the nucleus.
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How this classification was reachedexpand
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) | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".