Bibliographic record
Abstract
Non-viral delivery of genes involved in stimulation of bone formation has been pursued for clinical bone repair, but no effort has been made to assess protein expression levels after in vivo delivery. This is critical to better understand gene delivery efficiencies and to compare different modes of non-viral delivery. This study investigated expression levels of basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2) after delivering expression vectors (plasmid DNA) with polymeric carriers in a rat subcutaneous implant model. The polymers used were a 2 kDa molecular weight polyethylenimine modified with linoleic acid (PEI-LA) and the 25 kDa PEI (PEI25) used for non-viral gene delivery in animal models. The PEI-LA mediated delivery of the plasmid DNAs in 293T cells led to ∼3.5 and ∼13 ng/10(6) cells/day secretion of bFGF and BMP-2 in vitro, respectively. Using the reporter protein, Green Fluorescence Protein (GFP), transfection in implants was readily detected by the presence of GFP-positive cells and a polymeric carrier was needed for this GFP expression. No bFGF and BMP-2 were detected in the scaffolds due to high background in detection assays and/or rapid diffusion of the secreted proteins from the implant site. However, using an ex vivo culture system, significant levels of BMP-2, but not bFGF, secretion were observed from the scaffolds. The BMP-2 secretion from PEI-LA delivered expression vector was equivalent and/or superior to PEI25 depending on the plasmid DNA implant dose. Gelatin scaffolds were able to sustain ∼0.3 ng/sponge/day BMP-2 secretion as compared to collagen scaffolds (∼0.1 ng/sponge/day). These values were equivalent to secretion rates reported with some viral delivery systems from independent studies.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 0.002 |
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; both teacher heads agree on what is shown here.
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".