JoVE - Journal of Visualized Experiments
JoVE Visualize
Contact Us

pH-Sensitive Fluorescent Marker Based on Rhodamine 6G Conjugate with Its FRET/PeT Pair in "Smart" Polymeric Micelles for Selective Imaging of Cancer Cells

  • 0Faculty of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1/3, 119991 Moscow, Russia.
Pharmaceutics +

|

August 29, 2024

|

August 29, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Researchers developed a pH-sensitive fluorescent dye for cancer cell imaging. This smart micelle system targets tumor cells, enabling precise visualization with confocal laser scanning microscopy (CLSM).

Area Of Science

  • Biomedical Engineering
  • Chemical Biology
  • Materials Science

Background

  • Cancer cells create an acidic microenvironment due to the Warburg effect.
  • Fluorescent dyes are sensitive to pH, but practical imaging requires high quantum yield, low bleaching, and minimal quenching.
  • Existing fluorescent markers often lack pH sensitivity in the relevant biological range (5.5-7.5).

Purpose Of The Study

  • To develop a pH-sensitive fluorescent probe for selective cancer cell imaging.
  • To enhance the pH sensitivity of the R6G fluorophore for the acidic tumor microenvironment.
  • To enable improved visualization of cancer cells using confocal laser scanning microscopy (CLSM).

Main Methods

  • Covalent conjugation of R6G with NBD using a spermidine linker.
  • Incorporation of the R6G-NBD conjugate into "smart" polymeric micelles based on chitosan grafted with lipoic acid.
  • Evaluation of pH sensitivity and cellular uptake in cancer cells (A875, K562) and normal cells (HEK293T) using CLSM.

Main Results

  • The NBD-spd-R6G conjugate within chitosan-based micelles exhibited a sharp fluorescence increase (40% per pH unit) between pH 7.5 and 5.
  • The "smart" polymeric micelles demonstrated selective targeting and enhanced uptake in cancer cells compared to normal cells.
  • Efficient visualization of A875 and K562 cancer cells was achieved with minimal signal in HEK293T normal cells.

Conclusions

  • "Smart" polymeric micelles can effectively shift the pH-dependent fluorescence of probes to the desired biological range.
  • The developed pH-sensitive fluorophore and micelle system enables selective and efficient imaging of cancer cells.
  • This approach offers a versatile platform for regulating fluorescence pH dependence for visualizing various cellular structures.

Keywords: