title: Deep in vivo two-photon imaging of blood vessels with a new dye encapsulated in pluronic nanomicelles.
abstract: Our purpose is to test if Pluronic® fluorescent nanomicelles can be used for in vivo two-photon imaging of both the normal and the tumor vasculature. The nanomicelles were obtained after encapsulating a hydrophobic two-photon dye: di-stryl benzene derivative, in Pluronic block copolymers. Their performance with respect to imaging depth, blood plasma staining, and diffusion across the tumor vascular endothelium is compared to a classic blood pool dye Rhodamin B dextran (70 kDa) using two-photon microscopy. Pluronic nanomicelles show, like Rhodamin B dextran, a homogeneous blood plasma staining for at least 1 h after intravenous injection. Their two-photon imaging depth is similar in normal mouse brain, using 10 times less injected mass. In contrast with Rhodamin B dextran, no extravasation is observed in leaky tumor vessels due to their large size: 20-100 nm. In conclusion, Pluronic nanomicelles can be used as a blood pool dye, even in leaky tumor vessels. The use of Pluronic block copolymers is a valuable approach for encapsulating two-photon fluorescent dyes that are hydrophobic and not suitable for intravenous injection.
authors: Laboratoire de Spectrométrie Physique, CNRS UMR 5588, Saint Martin d'Hères, France.
authors: Mathieu
authors: M
authors: Maurin
authors: Olivier
authors: O
authors: Stéphan
authors: Jean-Claude
authors: JC
authors: Vial
authors: Seth R
authors: SR
authors: Marder
authors: Boudewijn
authors: B
authors: van der Sanden
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000033:anatomy & histology*; D001811:Blood Volume Determination; D001921:Brain / Q000098:blood supply; D045744:Cell Line, Tumor; D003911:Dextrans; D003952:Diagnostic Imaging; D005456:Fluorescent Dyes; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008823:Micelles; D018613:Microscopy, Confocal / Q000379:methods*; D049329:Nanostructures; D009374:Neoplasms, Experimental / Q000098:blood supply; D055620:Optical Phenomena; D017785:Photons; D020442:Poloxamer; D012235:Rhodamines; D013343:Styrenes
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes; D008823:Micelles; D012235:Rhodamines; D013343:Styrenes; C507243:distyrylbenzene; C051311:rhodamine dextran; D020442:Poloxamer