Ultrabright Fluorescent Polymeric Nanoparticles with Stealth Pluronic Shell for Live Tracking in Mouse Brain.
Fiche publication
Date publication
juillet 2020
Journal
ACS nano
Auteurs
Membres identifiés du Cancéropôle Est :
Dr KLYMCHENKO Andrey
Tous les auteurs :
Khalin I, Heimburger D, Melnychuk N, Collot M, Groschup B, Hellal F, Reisch A, Plesnila N, Klymchenko AS
Lien Pubmed
Résumé
Visualizing single organic nanoparticles (NPs) in vivo remains a challenge, which could greatly improve our understanding of the bottlenecks in the field of nanomedicine. To achieve high single-particle fluorescence brightness, we loaded polymer poly(methyl methacrylate)-sulfonate (PMMA-SO3H) NPs with octadecyl rhodamine B together with a bulky hydrophobic counterion (perfluorinated tetraphenylborate) as a fluorophore insulator to prevent aggregation-caused quenching. To create NPs with stealth properties we used the amphiphilic block copolymers pluronic F-127 and F-68. Fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) revealed that pluronics remained at the NP surface after dialysis (at one amphiphile per 5.5 nm2) and prevented NPs from non-specific interactions with serum proteins and surfactants. In primary cultured neurons, pluronics stabilized the NPs preventing their prompt aggregation and binding to neurons. By increasing dye loading to 20 wt% and optimizing particle size, we obtained 74-nm NPs showing 150-fold higher single-particle brightness with two-photon excitation than commercial Nile Red-loaded FluoSpheresTM of 39-nm hydrodynamic diameter. The obtained ultrabright pluronic-coated NPs enabled direct single-particle tracking in vessels of mice brain by two-photon intravital microscopy for at least 1h, whereas non-coated NPs were rapidly eliminated from the circulation. Following brain injury or neuroinflammation, which can open the blood-brain barrier, extravasation of NPs was successfully monitored. Moreover, we demonstrated tracking of individual NPs from meningeal vessels until their uptake by meningeal macrophages. Thus, single NPs can be tracked in animals at real-time in vivo in different brain compartments and their dynamics visualized with subcellular resolution.
Référence
ACS Nano. 2020 Jul 17;: