Fluorescently Labeled Gold Nanoparticles with Minimal Fluorescence Quenching
Bibliographic record
Abstract
Minimal quenching of fluorescence emission was observed when the fluorescent dye AlexaFluor 514 (AF514) was covalently bound to gold monolayer protected clusters (AuMPCs) that have negligible plasmon bands (diameters <2 nm). The fluorescence emission of the conjugated dye was measured as a function of dye−AuMPC mixing ratio with a combination of steady-state and time-resolved ensemble spectroscopic measurements in conjunction with single-molecule fluorescence microscopy. Fluorescence emission of the conjugated samples decreased slightly as a function of dye mixing ratio, which, in combination with a negligible change in fluorescence lifetime, was attributed to static quenching of the dye by the AuMPCs. From the single-molecule fluorescence measurements, it was observed that luminescent conjugates could still be detected, and, at all loading ratios, almost all of the dye−particle conjugates photobleached in either a single- or double-step process, with a small subpopulation exhibiting more than two photobleaching events. Beyond simple, irreversible photobleaching, no additional blinking dynamics were detected at the single-molecule level within the time resolution of the experiment. Emission intensities of coupled fluorophores were comparable with those measured of dye molecules that had not been attached to the AuMPCs, suggesting that the statically quenched fluorophores are entirely nonemissive, whereas the remaining dyes are essentially unquenched. These results are discussed in the context of other dye−AuMPC coupled systems described in the literature.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".