Tuning phenolic hemicyanines for ratiometric DNA sensing and live cell nuclear bioimaging applications
Bibliographic record
Abstract
Activatable fluorescent probes with turn-on emission in response to a biological target can reduce the background signal and improve the detection limit needed for biosensor and bioimaging resolution. Turn-on probes with dual emission (ratiometric probes) have further advantages, as they have self-calibration ability for more reliable detection. Herein, we demonstrate the tunability of the phenolic hemicyanine (HC) scaffold for both DNA biosensing and bioimaging applications using the quinine-binding DNA aptamer (MN4) as a host-guest biosensor platform and live ovarian cancer cells for nuclear imaging. The DNA aptamer MN4 contains a three-way junction (3WJ) consisting of a hydrophobic branch point connecting three double-stranded stems. Phenolic HCs bearing electron-withdrawing halogen substituents (FPhOBtz and Cl 2 PhOBTz) bind to the 3WJ of MN4 as the phenolate with strong turn-on emission. Subsequent displacement of the phenolate by the quinine target causes a turn-off emission response. In contrast, the parent phenolic HC (PhOBtz) and those bearing electron-donating groups (Me 2 PhOBtz and (MeO) 2 PhOBtz) exhibit dual (phenol and phenolate) fluorescence upon MN4 binding. Phenol excitation generates phenolate emission by an excited-state proton transfer (ESPT) process with DNA components serving as the proton acceptor. Quinine displacement of PhOBtz from the 3WJ of MN4 affords a turn-on ratiometric response with preferential light-up of phenol emission. The ability of the phenolic HCs to serve as cellular nuclear stains further highlights the tunability of the phenolic HC probes with the Cl 2 PhOBtz analog displaying superior staining ability. The simplicity and tunability of phenolic HCs make them attractive fluorescent probes for DNA sensing and bioimaging applications.
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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) | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".