Nano Research

, Volume 8, Issue 4, pp 1169–1179 | Cite as

Colourimetric redox-polyaniline nanoindicator for in situ vesicular trafficking of intracellular transport

  • Eun Bi Choi
  • Jihye Choi
  • Seo Ryung Bae
  • Hyun-Ouk Kim
  • Eunji Jang
  • Byunghoon Kang
  • Myeong-Hoon Kim
  • Byeongyoon Kim
  • Jin-Suck Suh
  • Kwangyeol Lee
  • Yong-Min HuhEmail author
  • Seungjoo HaamEmail author
Research Article


Vesicular pH modulates the function of many organelles and plays a pivotal role in cell metabolism processes such as proliferation and apoptosis. Here, we introduce a simple colorimetric redox-polyaniline nanoindicator, which can detect and quantify a broader biogenic pH range with superior sensitivity compared to pre-established trafficking agents employing one-dimensional turn-on of the fluorescence resonance-energy-transfer (FRET) signal. We fabricated polyaniline-based nanoprobes, which exhibited convertible transition states according to the proton levels, as an in situ indicator of vesicular transport pH. Silica-coated Fe3O4-MnO heterometal nanoparticles were synthesised and utilised as a metal oxidant to polymerise the aniline monomer. Finally, silica-coated polyaniline nanoparticles with adsorbed cyanine dye fluorophores Cy3 and Cy7 (FPSNICy3 and FPSNICy7) were fabricated as proton-sensitive nanoindicators. Owing to the selective quenching induced by the local pH variations of vesicular transport, FPSNICy3 and FPSNICy7 demonstrated excellent intracellular trafficking and provided sensitive optical indication of minute proton levels.


redox pH intracellular compartments organic quencher conducting polymer nanoindicator 


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Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Eun Bi Choi
    • 1
  • Jihye Choi
    • 1
  • Seo Ryung Bae
    • 1
  • Hyun-Ouk Kim
    • 1
  • Eunji Jang
    • 1
  • Byunghoon Kang
    • 1
  • Myeong-Hoon Kim
    • 1
  • Byeongyoon Kim
    • 3
  • Jin-Suck Suh
    • 2
  • Kwangyeol Lee
    • 3
  • Yong-Min Huh
    • 2
    Email author
  • Seungjoo Haam
    • 1
    Email author
  1. 1.Department of Chemical and Biomolecular Engineering, College of EngineeringYonsei UniversitySeoulRepublic of Korea
  2. 2.Department of Radiology, College of MedicineYonsei UniversitySeoulRepublic of Korea
  3. 3.Department of ChemistryKorea UniversitySeoulRepublic of Korea

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