Nile blue-based nano-sized pH sensors for simultaneous far-red and near-infrared live bioimaging

Jeppe Madsen, Irene Canton, Nicholas J Warren, Efrosyni Themistou, Adam Blanazs, Burcin Ustbas, Xiaohe Tian, Russell Pearson, Giuseppe Battaglia, Andrew L Lewis, Steven P Armes

Research output: Contribution to journalArticlepeer-review

86 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)14863-70
Number of pages8
JournalJournal of the American Chemical Society (JACS)
Issue number39
Early online date03 Sep 2013
Publication statusPublished - 02 Oct 2013

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

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