Alkylated derivatives of poly(ethylacrylic acid) can be inserted into preformed liposomes and trigger pH-dependent intracellular delivery of liposomal contents
Bibliographic record
Abstract
Poly(ethylacrylic acid) (PEAA) is a pH-sensitive polymer that undergoes a transition from a hydrophilic to a hydrophobic form as the pH is lowered from neutral to acidic values. In this work we show that pH sensitive liposomes capable of intracellular delivery can be constructed by inserting a lipid derivative of PEAA into preformed large unilamellar vesicles (LUV) using a simple one step incubation procedure. The lipid derivatives of PEAA were synthesized by reacting a small proportion (3%) of the carboxylic groups of PEAA with C10 alkylamines to produce C10-PEAA. Incubation of C10-PEAA with preformed LUV resulted in the association of up to 8% by weight of derivatized polymer with the LUV without inducing aggregation. The resulting C10-PEAA-LUV exhibited pH-dependent fusion and leakage of LUV contents on reduction of the external pH below pH 6.0 as demonstrated by lipid mixing and release of calcein encapsulated in the LUV. In addition, C10-PEAA-LUV exhibited pH dependent intracellular delivery properties following uptake into COS-7 cells with appreciable delivery to the cell cytoplasm as evidenced by the appearance of diffuse intracellular calcein fluorescence. It is demonstrated that the cytoplasmic delivery of calcein by C10-PEAA-LUV could be inhibited by agents (bafilomycin or chloroquine) that inhibit acidification of endosomal compartments, indicating that this intracellular delivery resulted from the pH-dependent destabilization of LUV and endosomal membranes by the PEAA component of the C10-PEAA-LUV. It is concluded that C10-PEAA-LUV represents a promising intracellular delivery system for in vitro and in vivo applications.
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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".