title: Nile Blue-based nanosized pH sensors for simultaneous far-red and near-infrared live bioimaging.
abstract: Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance.
authors.affiliation: Department of Biomedical Sciences, University of Sheffield , Sheffield, S10 2TN, United Kingdom.
authors.forename: Jeppe
authors.initials: J
authors.lastname: Madsen
authors.forename: Irene
authors.initials: I
authors.lastname: Canton
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Warren
authors.forename: Efrosyni
authors.initials: E
authors.lastname: Themistou
authors.forename: Adam
authors.initials: A
authors.lastname: Blanazs
authors.forename: Burcin
authors.initials: B
authors.lastname: Ustbas
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Tian
authors.forename: Russell
authors.initials: R
authors.lastname: Pearson
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Battaglia
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Lewis
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004337:Drug Carriers / Q000737:chemistry; D005456:Fluorescent Dyes / Q000008:administration & dosage* / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007259:Infrared Rays; D053758:Nanoparticles / Q000737:chemistry; D061848:Optical Imaging / Q000379:methods*; D010078:Oxazines / Q000008:administration & dosage* / Q000032:analysis*; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D018874:Spheroids, Cellular; D014407:Tumor Cells, Cultured
chemical_list: D004337:Drug Carriers; D005456:Fluorescent Dyes; D010078:Oxazines; D011109:Polymethacrylic Acids; C578682:poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-(2-(diisopropylamino)ethyl methacrylate); D010767:Phosphorylcholine; C008619:Nile Blue