Tail-end amphiphilic dimethylaminopyridinium-containing polymethacrylates for gene delivery
Bibliographic record
Abstract
Amphiphilic dimethylaminopyridinium alkyl polymethacrylates (aPPs) were tested for gene complexation, cell cytotoxicity and in vitro gene expression for use as gene delivery agents. The aminopyridinium groups neutralized by bromide or octylsulfonate counterions were terminal moieties of side-chain spacers containing 8, 12 or 16 methylene units. This investigation measured the impact of the spacer length and the chemical nature of the counterion on the physicochemical properties and biological activity of the polyplexes formed by the complexation with DNA. The aPPs self-assembled with DNA by neutralizing the DNA phosphate charges through the pyridinium moieties. The degree of DNA condensation was higher for shorter spacer (n = 8, 12) and bromide-neutralized aPPs. Several aPP–DNA complexes formed well-defined nanoparticles, which were usually, but not always, positively charged. Their sizes ranged from 30 to 150 nm and in some cases had an internal lamellar structure visible by TEM. All of the aPPs were found to be much less cytotoxic than branched poly(ethyleneimine) [(PEI), 25 kDa]. The degree of cytotoxicity of the aPPs depended mildly on their spacer length and counterion: a longer spacer (n = 16) decreased the cell viability more than shorter spacers and, at the highest aPP concentrations tested, bromide counterions more than octylsulfonate counterions. The transfection efficiency also depended on the spacer length and counterion type. Polyplexes obtained from the bromide-neutralized aPPs with the n = 12 spacer at an aPP/DNA weight ratio of 2.5, for which negatively charged nanoparticles were formed, were found to be as efficient as PEI-based polyplexes. Interestingly, this demonstrates that endosomolytic fragments and positively charged polyplex surfaces are not required for efficient gene expression.
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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".