Advertisement

A Fluorescent Flavonoid for Lysosome Imaging: the Effect of Substituents on Selectivity and Optical Properties

  • Keti Assor Bertman
  • Chathura S. Abeywickrama
  • Ashley Ingle
  • Leah P. Shriver
  • Michael Konopka
  • Yi PangEmail author
ORIGINAL ARTICLE
  • 65 Downloads

Abstract

Lysosome selective bright orange-red emitting flavonoid (2) was synthesized by attaching a strong donor (NPh2) group into flavonoid skeleton. As a result of efficient intra molecular charge transfer due to the strong donor group, a significant bathochromic shift was observed from the emission of 2b (with a –NPh2 group, λem ≈ 590 nm), in comparison that of 1b (with a –NMe2 group, λem ≈ 519 nm). The role of the substituent effect towards ICT was further studied by low temperature spectral analysis. Fluorescence spectra at low temperature confirmed that large Stokes shift for probe 2 (Δλ ≈ 150 nm) was due to strong ICT. Probe 2b exhibited exceptional selectivity towards cellular lysosomes in live cells studies thus generating bright orange-red emission upon localization. Intra-cellular pH analysis results confirmed that probe 2b did not participate in the elevation of lysosomal pH upon staining with different probe concentrations (0.5 μM – 2.0 μM) which is a potential advantage compared to acidotropic commercial LysoTracker® probes. This study further illustrated that the substituents in probe 2 play a significant role towards probe’s organelle selectivity since probe 2a (R = OH) did not show any lysosomal localization compared with 2b. In addition, the calculated cytotoxicity data further revealed that this new probe design is highly biocompatible (LC50 > 50 μM) and suitable for long term imaging.

Graphical Abstract

Keywords

Excited state intra-molecular proton transfer (ESIPT) Intra-molecular charge transfer (ICT) Stokes shift Flavonoid Substituent effect Lysosome probes 

Notes

Acknowledgments

We acknowledge partial support from Coleman Endowment from The University of Akron. We thank Nicolas Alexander from The University of Akron for acquiring mass spectra data. We also thank Hannah J Baumann from The University of Akron for conduction MTT cell viability assays. The NHLF cell line was a kind gift from Dr. Sailaja Paruchuri at The University of Akron.

Supplementary material

10895_2019_2371_MOESM1_ESM.docx (5.4 mb)
ESM 1 (DOCX 5.37 mb)

References

  1. 1.
    Johnson I, Spence MTZ (2010) The handbook: a guide to fluorescent probes and labeling technologiesGoogle Scholar
  2. 2.
    Zhang J, Campbell RE, Ting AY, Tsien RY (2002) Creating new fluorescent probes for cell biology. Nat Rev Mol Cell Biol 3:906–918CrossRefGoogle Scholar
  3. 3.
    Wiederschain GY (2011) The molecular probes handbook. A guide to fluorescent probes and labeling technologies. Biochem 76:1276–1276Google Scholar
  4. 4.
    McDonald L, Liu B, Taraboletti A, Whiddon K, Shriver LP, Konopka M, Liu Q, Pang Y (2016) Fluorescent flavonoids for endoplasmic reticulum cell imaging. J Mater Chem B 4:7902–7908CrossRefGoogle Scholar
  5. 5.
    Liu B, Shah M, Zhang G, Liu Q, Pang Y (2014) Biocompatible flavone-based fluorogenic probes for quick wash-free mitochondrial imaging in living cells. ACS Appl Mater Interfaces 6:21638–21644CrossRefGoogle Scholar
  6. 6.
    Havsteen BH (2002) The biochemistry and medical significance of the flavonoidsGoogle Scholar
  7. 7.
    Zhao C, Liu B, Bi X, Liu D, Pan C, Wang L, Pang Y (2016) A novel flavonoid-based bioprobe for intracellular recognition of Cu2+ and its complex with Cu2+ for secondary sensing of pyrophosphate. Sensors Actuators B Chem 229:131–137CrossRefGoogle Scholar
  8. 8.
    Pietta PG (2000) Flavonoids as antioxidants. J Nat Prod 63:1035–1042CrossRefGoogle Scholar
  9. 9.
    Hertog MGL, Feskens EJM, Kromhout D, Hertog MGL, Hollman PCH, Hertog MGL, Katan MB (1993) Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen elderly study. Lancet 342:1007–1011CrossRefGoogle Scholar
  10. 10.
    Litvinov VP (2007) Chemistry and biological activities of 1,8-naphthyridines. Russ Chem Rev 73:637–670CrossRefGoogle Scholar
  11. 11.
    Chahar MK, Sharma N, Dobhal MP, Joshi YC (2011) Flavonoids: a versatile source of anticancer drugs. Pharmacogn Rev 5:1–12CrossRefGoogle Scholar
  12. 12.
    Cushnie TPT, Lamb AJ (2005) Antimicrobial activity of flavonoids. Int J Antimicrob Agents 26:343–356CrossRefGoogle Scholar
  13. 13.
    Cooper G (2000) The Cell: A Molecular Approach, 2nd ed. Sinauer Associates, Sunderland (MA)Google Scholar
  14. 14.
    Chen X, Bi Y, Wang T, Li P, Yan X, Hou S, Bammert CE, Ju J, Gibson KM, Pavan WJ, Bi L (2015) Lysosomal targeting with stable and sensitive fluorescent probes (superior LysoProbes): applications for lysosome labeling and tracking during apoptosis. Sci Rep 5:9004–9013CrossRefGoogle Scholar
  15. 15.
    Bertman KA, Abeywickrama CS, Baumann HJ, Alexander N, McDonald L, Shriver LP, Konopka M, Pang Y (2018) A fluorescent flavonoid for lysosome detection in live cells under “wash free” conditions. J Mater Chem B 6:5050–5058CrossRefGoogle Scholar
  16. 16.
    Novakova V, Hladík P, Filandrová T, Zajícová I, Krepsová V, Miletin M, Lenčo J, Zimcik P (2014) Structural factors influencing the intramolecular charge transfer and photoinduced electron transfer in tetrapyrazinoporphyrazines. Phys Chem Chem Phys 16:5440–5446CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Keti Assor Bertman
    • 1
  • Chathura S. Abeywickrama
    • 1
  • Ashley Ingle
    • 1
  • Leah P. Shriver
    • 1
    • 2
  • Michael Konopka
    • 1
  • Yi Pang
    • 1
    • 3
    Email author
  1. 1.Department of ChemistryUniversity of AkronAkronUSA
  2. 2.Department of BiologyUniversity of AkronAkronUSA
  3. 3.Maurice Morton Institute of Polymer ScienceUniversity of AkronAkronUSA

Personalised recommendations