Intracellular O2 sensing probe based on cell-penetrating phosphorescent nanoparticles

Area of Science:

• Biomedical Engineering
• Cell Biology
• Analytical Chemistry

Background:

• Accurate measurement of intracellular oxygen (icO(2)) is crucial for understanding cellular metabolism and disease.
• Existing methods for icO(2) sensing often face limitations in sensitivity, stability, or applicability to live-cell imaging.

Purpose of the Study:

• To develop and characterize a novel nanoparticle-based probe for quantitative intracellular oxygen sensing.
• To evaluate the probe's performance in live mammalian cells, including uptake, localization, and signal stability.

Main Methods:

• Fabrication of nanoparticles (NPs) using Eudragit RL-100 and a phosphorescent dye (PtPFPP).
• Investigation of NP cellular uptake via confocal microscopy and flow cytometry.
• Calibration of phosphorescence lifetime signals to determine icO(2) concentration.
• Monitoring of cellular metabolic responses in mouse embryonic fibroblast cells.

Main Results:

• NPs are efficiently internalized by cells via energy-dependent endocytosis and localize near the nucleus.
• The probe provides stable, reproducible signals across various cell types.
• Phosphorescence lifetime measurements accurately correlate with intracellular oxygen levels.
• The probe successfully monitors metabolic responses to ambient and hypoxic conditions.

Conclusions:

• The developed nanoparticle probe offers a robust and quantitative method for intracellular oxygen sensing in live cells.
• Its high brightness and photostability make it suitable for both high-throughput screening and single-cell analysis.
• This tool has significant potential for advancing research in cellular physiology and disease diagnostics.