Pluronic Organic Fluorescent Probes for Two-photon Vascularisation Imaging

Bio-compatible nanosized probes exhibiting high two-photon fluorescence efficiency were fabricated using oil-in-water micro-emulsification of a hydrophobic chromophore with polyethylene-polypropylene glycol (Pluronic). This process leads, after oil removal and mechanical filtration, to hydrophilic vehicles, with dimensions below 100 nm, trapping fluorescent organic dyes. The resulting amount of incorporated fluorescent material within particles was investigated for three chromophores (fluorene dimer, rubrene, a di-stryl benzene derivative) and two Pluronics copolymers. The fluorescence of the corresponding spherical particles, dispersed in thin Bovine Serum Albumin film, is also reported. The distryl benzene derivative, incorporated in the most hydrophobic Pluronic, was chosen for two-photon imaging of the microvasculature of the living mouse brain cortex.