Use of Merocyanine 540 for Photodynamic Inactivation of <i>Staphylococcus aureus</i> Planktonic and Biofilm Cells
Bibliographic record
Abstract
Photodynamic inactivation of Staphylococcus aureus planktonic and biofilm cells by a phtotosensitizer, merocyanine 540 (MC 540), was investigated. For the planktonic experiments, MC 540 binding efficiency to bacterial cells was found to increase with both increasing MC 540 concentration and increasing incubation time, but the binding became saturated following 10 min of incubation. The antimicrobial activity was enhanced with an increasing light dose, but an increase in the light dose could not further improve the antimicrobial activity if the maximum excitation level attainable was less than the necessary minimum threshold level. Complete inactivation was achieved when the excitation level of MC 540 was somewhere above the threshold level. The relationship between antimicrobial activity and the excitation level of MC 540 revealed that the more MC 540 was excited, the more S. aureus cells were killed. For the biofilm experiments, the antimicrobial activity was enhanced with an increase in the light dose. No viable cells were detected when organisms were exposed to 15 mug of MC 540 per ml and a light dose of 600 J/cm2 or to 20 mug of MC 540 per ml and a light dose of 450 J/cm2. A quantitative analysis of MC 540 bound to biofilms was also performed, and the images from confocal laser scanning microscopy provided direct evidence that revealed the difference between the MC 540 remaining in the biofilms prior to irradiation and the MC 540 remaining in the biofilms after irradiation. The results of both the planktonic and biofilm experiments suggest that the antimicrobial activity of photodynamic inactivation of S. aureus is closely related to the excitation level of MC 540.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.000 |
| 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 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".