The internal structure of gadolinium and perfluorocarbon-loaded polymer nanoparticles affects F MRI relaxation times.

F magnetic resonance imaging (F MRI) is an emerging technique for quantitative imaging in novel therapies, such as cellular therapies and theranostic nanocarriers. Nanocarriers loaded with liquid perfluorocarbon (PFC) typically have a (single) core-shell structure with PFC in the core due to the poor miscibility of PFC with organic and inorganic solvents. Paramagnetic relaxation enhancement acts only at a distance of a few angstroms.

In Vivo PET Imaging of Monocytes Labeled with [Zr]Zr-PLGA-NH Nanoparticles in Tumor and Infection Models.

The exponential growth of research on cell-based therapy is in major need of reliable and sensitive tracking of a small number of therapeutic cells to improve our understanding of the in vivo cell-targeting properties. In-labeled poly(lactic--glycolic acid) with a primary amine endcap nanoparticles ([In]In-PLGA-NH NPs) were previously used for cell labeling and in vivo tracking, using SPECT/CT imaging. However, to detect a low number of cells, a higher sensitivity of PET is preferred.

Characterization of Intrinsically Radiolabeled Poly(lactic--glycolic acid) Nanoparticles for ex Vivo Autologous Cell Labeling and in Vivo Tracking.

With the advent of novel immunotherapies, interest in ex vivo autologous cell labeling for in vivo cell tracking has revived. However, current clinically available labeling strategies have several drawbacks, such as release of radiolabel over time and cytotoxicity. Poly(lactic--glycolic acid) nanoparticles (PLGA NPs) are clinically used biodegradable carriers of contrast agents, with high loading capacity for multimodal imaging agents.