Polymer-Stabilized Lanthanide Fluoride Nanoparticle Aggregates as Contrast Agents for Magnetic Resonance Imaging and Computed Tomography
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Poly(acrylic acid) consisting of 25 monomer units (PAA 25 ) was used to stabilize nanoparticle aggregates (NPAs) consisting of either NaGdF 4 or 50/50 mixtures of GdF 3 and CeF 3 . The resulting polymer-stabilized nanoparticle aggregates (NPAs) were developed and tested for their application as contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT). The PAA 25 -stabilized NPAs exhibit low polydispersity and are colloidally stable at concentrations of 40 mg/mL, while their sizes can be be controlled by choosing a specific ratio of Gd 3+ to Ce 3+ . Scanning transmission electron microscopy (STEM) reveals that NaGdF 4 NPAs possess an average diameter of 400 nm. High-resolution STEM and powder X-ray diffraction (XRD) both show that these NPAs consist of a stable aggregate of smaller NPs, whose diameters are 20−22 nm. PAA 25 -stabilized NPAs consisting of a 50/50 mixture of GdF 3 and CeF 3 possess an average diameter of 70 nm, while the fundamental unit size is estimated to be 10−12 nm in diameter. The PAA 25 -stabilized GdF 3 /CeF 3 NPAs possess mass relaxivities of 40 ± 2 and 30 ± 2 s −1 (mg/mL) −1 at 1.5 T and 3.0 T, respectively. Their effectiveness as contrast agents for CT X-ray imaging at various X-ray energies was also tested and compared to that of equivalent mass concentrations of Gd 3+ -diethylene triamine pentaacetic acid (Gd 3+ -DTPA) and iopromide. Gd-based NPAs exhibit superior CT contrast to equal-mass concentrations of either iopromide or Gd 3+ -DTPA below 30 keV and above 50 keV. Finally, PAA 25 was functionalized by folic acid to explore targeted imaging. Confocal microscopy revealed that, by functionalizing the PAA 25 -stabilized NaGdF 4:Tb 3+ NPAs with ∼0.8 folates per polymer, binding and endocytosis occurred in SK-BR-3 human breast cancer cells. The utility of the PAA 25 -stabilized GdF 3 /CeF 3 NPAs for MRI is demonstrated in rat perfusion MRI experiments, where T 1 -weighted MRI images of equivalent concentrations of either Gd 3+ -DTPA or the above NPAs are directly compared. The high relaxivities provide an opportunity to conduct perfusion MRI experiments with significantly lower concentrations than those needed for current commercial agents.
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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 | 0.000 | 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) | 0.002 | 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 it