Boron neutron capture therapy (BNCT), a binary
cancer therapeutic modality, has moved to a new phase since development of accelerator-based neutron sources and establishment of BNCT centers in Finland and Japan. That stimulated efforts for better
boron delivery agent development. As
liposomes have shown effective
boron delivery properties and sufficient
tumor retention, fluorescent
liposome labelling may serve as a rapid method to study initial ability of newly synthesized
liposomes to be captured by
tumor cells prior to experiments on
boron accumulation and neutron irradiation. In this work, we studied the accumulation and biodistribution of pegylated
liposomes with encapsulated borocaptate (BSH) and a fluorescent label (
Nile Red) in U87 (human
glioblastoma), SW-620 (human colon
carcinoma), SK-MEL-28 (human
melanoma), FetMSC (mesenchymal human embryo stem cells), and EMBR (primary embryocytes) cell lines as well as an orthotopic xenograft model of U87
glioma in SCID mice. Results indicate that fluorescent microscopy is effective at determining the intracellular localization of the
liposomes using a fluorescent label. The synthesized, pegylated
liposomes showed higher accumulation in
tumors compared to normal cells, with characteristic concentration peaks in SW-620 and U87 cell lines, and provided in vivo
tumor selectivity with several-fold higher
tumor tissue fluorescence at the 6-h timepoint. Graphical abstract Fluorescent images of U-87
glioma cells after 24 hours of incubation with BSH-containing
liposomes labeled with lipophilic
Nile Red (red color)and water-soluble
FITC-Dextran (green color); cell nuclei in blue color (
DAPI-staining) (×400). Scale bar is 50 μm. Fluorescent labelling serves as anexpress method to study
liposome delivery efficiency prior to
boron accumulation evaluation and BNCT irradiation experiments.