New Enzyme-Activated Solubility-Switchable Contrast Agent for Magnetic Resonance Imaging: From Synthesis to in Vivo Imaging
Bibliographic record
Abstract
We designed and synthesized a novel contrast agent (CA) to image the activity of matrix metalloproteinase-2 (MMP-2) in a tumor, noninvasively using magnetic resonance imaging (MRI). We exploited the concept of solubility-switchable CAs in the design of a protease-modulated CA (PCA), referred to as PCA2-switch. This PCA contains a paramagnetic gadolinium chelate (Gd-DOTA), which was attached to the N-terminus of a MMP-2 cleavable peptide sequence via a hydrophobic chain. The aqueous solubility of the CA depends on the presence of a polyethylene glycol chain (PEG) on the C-terminus of the peptide. Upon proteolytic cleavage of the peptide by MMP-2, the PEG chain is detached from the CA, which becomes less water soluble. This compound and control compounds were successfully tested in an animal model bearing two tumors with different levels of MMP-2 activity.
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".