Journal of the Iranian Chemical Society

, Volume 16, Issue 3, pp 535–543 | Cite as

Nile red-doped fluorescent semiconducting polymer dots as a highly sensitive hydrophobicity probe: protein conformational changes detection and plasma membrane imaging

  • Ammar Chabok
  • Ali Yeganeh-FaalEmail author
  • Behnam Hajipour-Verdom
  • Behnaz Shojaedin-Givi
  • Mojtaba Shamsipur
Original Paper


One-pot synthesis of a photostable, hydrophobic and green fluorescent probe remains a challenge to develop luminescent biomaterials as well as biomedia technology. Semiconducting polymer dots (PDs) hold a great promise as fluorescence nanoprobes due to their photostability, biocompatibility and high quantum yield. Here, the synthesis and characterization of Nile red-doped PFBT PDs as a highly sensitive hydrophobicity probe has been reported. Nile red, a phenoxazone dye, fluoresces intensely in organic solvents and hydrophobic lipids and in varying color; however its fluorescence is totally quenched in water. First, Nile red-doped poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-(2,1′,3)-thiadiazole)] (PFBT) PDs were synthesized through a nano-precipitation technique. Energy transfer from PFBT to Nile red happens through FRET mechanism. The PDs exhibited a red fluorescence with a peak centered at 620 nm (photo-excited at 460 nm). In aqueous media, the fluorescence strongly quenched, but by increasing the hydrophobicity the fluorescence of PDs significantly enhances as the polarity of the medium decreases. This can happen by adding organic solvents or nonpolar species to the medium. The Nile red@PFBT PDs have remarkable specification over Nile red dye. Compared to Nile red, this probe is soluble in water, more photostable, and more brightness due to light-harvesting ability of PDs and less wavelength shift in different medium polarity. We used this probe to investigate polarity of different organic solvents, to study surface hydrophobicity changes of BSA and also Ca2+ determination due to conformational changes of calmodulin. Also we used this probe for imaging of lipid bilayers and cellular membrane.


Semiconducting polymer dots Nile red Polarity nanoprobe Hydrophobicity Cell membrane imaging, protein conformational changes 



The financial support of this work by Research Councils of Tarbiat Modares and Razi Universities is gratefully acknowledged. We also thank Payame Noor University, Qom Branch, for the laboratory support.


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Copyright information

© Iranian Chemical Society 2018

Authors and Affiliations

  • Ammar Chabok
    • 1
  • Ali Yeganeh-Faal
    • 2
    Email author
  • Behnam Hajipour-Verdom
    • 3
  • Behnaz Shojaedin-Givi
    • 4
  • Mojtaba Shamsipur
    • 5
  1. 1.Department of ChemistryTarbiat Modares UniversityTehranIran
  2. 2.Department of ChemistryPayame Noor UniversityTehranIran
  3. 3.Department of Biophysics, Faculty of Biological SciencesTarbiat Modares UniversityTehranIran
  4. 4.Department of Nanobiotechnology/BiophysicsTarbiat Modares UniversityTehranIran
  5. 5.Department of ChemistryRazi UniversityBākhtarānIran

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