Nanomaterials have emerged as valuable tools in biomedical imaging techniques, such as magnetic resonance imaging (MRI), fluorescence, positron emission tomography (PET), and others. Some have been designed to serve as multimodal imaging agents, combining seemingly disparate techniques such as fluorescence, photoacoustic tomography (PAT), or positron emission tomography (PET) with magnetic resonance imaging (MRI). Combining different imaging modalities into a single contrast agent enables one to capture meaningful images at different levels of spatial resolution from the same sample. Here, the one-step synthesis of a colloidally stable, fluorinated polymeric nanoparticle suitable for secondary ion mass spectrometry (SIMS) imaging and MRI is reported. The nanoparticles had a size distribution with maxima at 250 nm and 700 nm according to dynamic light scattering. After adding Tween-20 and sonicating for 4 hours, the distribution maxima shifted to 250 nm and 550 nm. Secondary ion mass spectrometry showed a strong fluorine signal, suggesting that the nanoparticles would be suitable for SIMS imaging techniques. Solid-state 19F-NMR (ssNMR) was used to help further elucidate the structure of the particles and validate their use as MRI contrast agents. The spectrum suggests that in vivo studies will require selective excitation due to the different fluorine chemical shifts present in the particles.
Citation: Macromolecular Rapid Communications
Pub Type: Journals
diagnostic imaging, fluorinated contrast agents, free radical polymerization, magnetic resonance imaging, SIMS