Redox-Based Photostabilizing Agents in Fluorescence Imaging: The Hidden Role of Intersystem Crossing in Geminate Radical Ion Pairs
Bibliographic record
Abstract
Here we report transient absorption studies on the ground-state recovery dynamics of the single-molecule fluorophore Cy3B in the presence of four different photostabilizing agents, namely β-mercaptoethanol (β-ME), Trolox (TX), n-propyl gallate (n-PG), and ascorbic acid (AA). These are triplet-state quenchers that operate via photoinduced electron transfer (PeT). While quantitative geminate recombination was recorded following PeT for β-ME (∼100%), for Trolox, n-propyl gallate, and ascorbic acid the extent of geminate recombination was >48%, >27%, and >13%, respectively. The results are rationalized in terms of the rates of intersystem crossing (ISC) in the newly formed geminate radical ion pairs (GRIPs). Rapid spin relaxation in the radicals formed accounts for quantitative geminate recombination with β-ME and efficient geminate recombination with TX. Our results illustrate how the interplay of PeT quenching efficiency and geminate recombination dynamics may lead to improved photostabilization strategies, critical for single-molecule fluorescence and super-resolution imaging.
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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 | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".