Characterization of the Long-Range Internal Dynamics of Pyrene-Labeled Macromolecules by Pyrene Excimer Fluorescence
Bibliographic record
Abstract
The long-range internal dynamics (LRID) of 74 pyrene-labeled macromolecules (PyLMs) were characterized in four solvents representing a broad range of dielectric constants equal to 2.4 (toluene), 7.6 (tetrahydrofuran, THF), 37.8 ( N, N -dimethylformamide, DMF), and 46.7 (dimethyl sulfoxide, DMSO). The LRID of the PyLMs were quantified based on the parameters retrieved from the global model free analysis (MFA) of the time-resolved fluorescence (TRF) decays of the pyrene monomer and excimer. These parameters were combined to yield ⟨ k ⟩, the average rate constant of pyrene excimer formation in the PyLMs, and ( I E / I M ) TRF ( f free = 0), the ratio of excimer to monomer fluorescence intensity obtained in the absence of pyrene labels that do not form excimer. ( I E / I M ) TRF ( f free = 0) was found to increase linearly with increasing ⟨ k ⟩ values over 3 orders of magnitude in the four solvents studied with a slope that equaled the average lifetime of the pyrene excimer (τ E ). The ⟨ k ⟩ values obtained to build these master lines could be correlated back to the expected LRID of the macromolecules. The lowest ⟨ k ⟩ values were obtained for the end-labeled linear chains holding the pyrene groups far apart, whereas the branched macromolecules bringing the pyrene labels close to each other yielded the larger ⟨ k ⟩ values. Furthermore, the fact that these master curves were observed for so many different PyLMs in the four solvents covering such a broad range of solvent polarity suggests that this relationship represents a general physical phenomenon that applies to all PyLMs. Considering the importance of characterizing the LRID of macromolecules in solution, the ( I E / I M ) TRF ( f free = 0) vs ⟨ k ⟩ plots presented in this report can be viewed as calibration curves against which the LRID of any PyLM can now be compared. Thus, the 3 orders of magnitude range found for these master curves offers the scientific community an impressive analytical opportunity to gauge the LRID of macromolecules in solution.
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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 | 0.001 | 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".