Long-Term Quantitatively Imaging Intracellular Chloride Concentration Using a Core-/Shell-Structured Nanosensor and...

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Chloride ion concentration is critical for cellular functions.
• Existing methods for intracellular chloride sensing face limitations in stability and photobleaching.

Purpose of the Study:

• To develop a robust nanosensor for quantitative intracellular chloride ion detection.
• To utilize time-domain dual-lifetime referencing (td-DLR) for improved sensor performance.

Main Methods:

• Incorporation of a ruthenium dye ([Ru(1,10-phenanthroline)₃]) within silica nanoparticles.
• Surface functionalization with chloride-sensitive fluorescent dyes (N,N'-bis(carboxypropyl)-9,9'-biacridine) and amino groups.
• Utilizing pulsed excitation for time-domain dual-lifetime referencing (td-DLR) to analyze luminescence lifetime.

Main Results:

• Developed 52 nm monodispersed silica nanoparticles with enhanced intracellular uptake.
• Achieved stable and reproducible measurements by minimizing photobleaching using td-DLR.
• Quantitatively imaged intracellular chloride concentration variations in lysosomes with high spatial resolution (0-200 mM range).

Conclusions:

• Luminescence lifetime-based nanosensors offer a stable and sensitive platform for intracellular chloride monitoring.
• The td-DLR approach significantly enhances measurement reliability for long-term cellular studies.
• This technology enables precise quantitative imaging of chloride dynamics in subcellular compartments like lysosomes.