Highly sensitive naphthalimide-based fluorescence polarization probe for detecting cancer cells

Area of Science:

• Biochemistry
• Analytical Chemistry
• Cell Biology

Background:

• Fluorescence polarization (FP) offers advantages over fluorescence intensity due to its self-referencing nature and reduced susceptibility to environmental factors.
• Existing FP probes often use dyes with shorter excited-state lifetimes, limiting sensitivity and stability.
• Naphthalimide dyes possess longer excited-state lifetimes and higher photostability, making them promising for advanced FP probe development.

Purpose of the Study:

• To design and synthesize a novel naphthalimide-based fluorescence polarization probe (BIO) for selective and direct cancer cell detection.
• To evaluate the probe's sensitivity, accuracy, and response time for quantifying cancer cells.
• To demonstrate the probe's utility in live cell imaging and its specific interaction with CD44-overexpressing cells.

Main Methods:

• Synthesis of a naphthalimide-based fluorescence polarization probe (BIO).
• Quantitative analysis of HeLa cells in homogeneous solution using FP spectroscopy.
• Live cell imaging of cancer cells using confocal microscopy under continuous irradiation.

Main Results:

• The BIO probe achieved a sensitive detection limit of approximately 85 cells/mL for HeLa cells.
• A linear detection range from 2.5 × 10^2 to 1 × 10^6 cells/mL was established with a response time under 25 minutes.
• The probe enabled clear visualization of specific interactions with CD44-overexpressing cell lines, suitable for live cell imaging due to naphthalimide's photostability.

Conclusions:

• The developed naphthalimide-based FP probe (BIO) provides a sensitive, accurate, and direct method for cancer cell detection.
• BIO's superior photostability and longer excited-state lifetime enhance its performance for quantitative analysis and live cell imaging.
• This sensing platform represents a direct, real-time tool for cancer cell diagnosis and research.