title: Intracellular uptake and trafficking of difluoroboron dibenzoylmethane-polylactide nanoparticles in HeLa cells.
abstract: In this study, nanoparticles based on difluoroboron dibenzoylmethane-poly(lactic acid) (BF(2)dbmPLA) are prepared. Polylactic acid or polylactide is a commonly used degradable polymer, while the boron dye possesses a large extinction coefficient, high emission quantum yield, two-photon absorption, and sensitivity to the surrounding environment. BF(2)dbmPLA exhibits molecular-weight-dependent emission properties and can be formulated as stable nanoparticles, suggesting that its unique optical properties may be useful in multiple contexts for probing intracellular environments. Here we show that BF(2)dbmPLA nanoparticles are internalized into cultured HeLa cells by endocytosis, and that within the cellular milieu, they retain their fluorescence properties. BF(2)dbmPLA nanoparticles are photostable, resisting laser-induced photobleaching under conditions that destroy the fluorescence of a common photostable probe, LysoTracker Blue. Their endocytosis is also lipid-raft-dependent, as evidenced by their significant colocalization with cholera toxin B subunit in membrane compartments after uptake and their sensitivity of uptake to methyl-beta-cyclodextrin. Additionally, BF(2)dbmPLA nanoparticle endocytosis utilizes microtubules and actin filaments. Internalized BF(2)dbmPLA nanoparticles do not accumulate in acidic late endosomes and lysosomes but within a perinuclear nonlysosomal compartment. These findings demonstrate the feasibility of using novel BF(2)dbmPLA nanoparticles exhibiting diverse emission properties for in situ, live cell imaging and suggest that their endogenous uptake occurs through a lipid-raft-dependent endocytosis mechanism.
authors.affiliation: Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90033.
authors.forename: Janette
authors.initials: J
authors.lastname: Contreras
authors.forename: Jiansong
authors.initials: J
authors.lastname: Xie
authors.forename: Yin Jie
authors.initials: YJ
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Pei
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhang
authors.forename: Cassandra L
authors.initials: CL
authors.lastname: Fraser
authors.forename: Sarah F
authors.initials: SF
authors.lastname: Hamm-Alvarez
mesh_terms: D001692:Biological Transport; D001896:Boron Compounds / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D055620:Optical Phenomena; D011091:Polyesters / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity
chemical_list: D001896:Boron Compounds; D011091:Polyesters; C522801:difluoroboron dibenzoylmethane polylactide