Delivery of nanoparticles to the brain detected by fluorescence microscopy

This study aimed to explore and extend the application potential of poly(n-butylcyano-acrylate) (PBCA) nanoparticles to cross the blood–brain barrier (BBB) and to deliver their content into the central nervous system. PBCA particles were prepared by a new and efficient mini-emulsion method with excellent yield and reproducibility. These nanoparticles were loaded with 1.5% (w/v) fluorescein-isothio-cyanate-dextran (FITC-dextran), 1.5% rhodamine-123 or 7.3% doxorubicin. Particles were characterized by dynamic light scattering determining particle size, polydispersity index and ζ-potential. They were coated with 10% w/v polysorbate 80 and administered to rats. Cryosections of the brain were prepared and time-dependent distribution of fluorescence was studied. After the administration of polysorbate 80-coated particles by carotic injection, fluorescence could first be detected in capillary lumina with a progressive shift to capillary endothelial cells at 30 min and a rather evenly spread distribution across the brain tissue at 60 min after administration. 60 min after administration into the tail vein, fluorescent particles could be assigned to endothelial cells, whereas after 2 h a rather evenly spread distribution across the brain tissue was seen. These observations indicate that surface-coated PBCA nanoparticles are able to cross the blood–brain barrier and to serve as a drug-delivery system to the central nervous system.