Characterization of Fluorescent Phospholipid Liposomes Entrapped in Sol−Gel Derived Silica
Bibliographic record
Abstract
Bilayer lipid membranes (BLMs) have been widely examined as sensing elements for a variety of analytes, in both the vapor and solution phases, using electrochemical, acoustic wave, and fluorescence methods. For successful development of stable sensing devices, it is necessary to be able to immobilize the BLMs in a manner that allows long-term retention of the membrane structure and still permits large-scale structural reorganizations such as phase transitions. In this work, small unilamellar liposomes were formed from either 1,2-dipalmitoyl- sn -glycero-3-phosphocholine (DPPC) or l -a-phosphatidylcholine (egg PC) and were doped with 1−5 mol % of the fluorescent probes diphenylhexatriene (DPH) or nitrobenzoxadiazole-labeled dipalmitoylphosphatidylethanolamine (NBD-PE). The liposomes were entrapped in a series of different sol−gel derived silicate materials and the stability and phase-transition behavior of the liposomes was characterized. DPPC was observed to undergo reversible phase transitions when entrapped in glasses derived from either sodium silicate or a diglyceryl silane precursor; however, liposomes did not undergo phase transitions when entrapped in tetraethyl orthosilicate derived glasses, indicating that they had likely ruptured during the encapsulation process. As a practical demonstration of the use of the immobilized membranes for sensing applications, we have examined the use of pH-induced phase transitions as a means of generating a fluorescence signal that is based on changes in self-quenching of NBD-PE within liposomes composed of DPPC and dipalmitoylphosphatidic acid (DPPA). The results show that such pH-induced phase transitions occur for the entrapped vesicles and that the fluorescence responses follow the pH dependence of DPPA.
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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 | 0.000 |
| 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 | 0.000 |
| 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 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".