Intracellular Zinc Quantification by Fluorescence Imaging with a FRET System

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Cell Biology

Background:

• Fluorescence imaging is widely used for cellular analysis, but intracellular metal quantification remains a significant challenge.
• Existing methods lack the precision required for accurate intracellular metal measurements.

Purpose of the Study:

• To develop a ratiometric probe for precise intracellular zinc quantification using fluorescence imaging.
• To establish a method for real-time monitoring of intracellular zinc dynamics.

Main Methods:

• Designed a ratiometric probe utilizing fluorescence resonance energy transfer (FRET) between carbon dots (CDs) and fluorescein (FAM).
• Employed a Zn2+ aptamer on CDs and a complementary DNA sequence on FAM for enhanced selectivity.
• Validated the probe in MCF-7 cells, correlating fluorescence imaging data with ICPMS measurements for intracellular zinc content.

Main Results:

• Achieved a linear correlation between the relative fluorescence ratio and intracellular zinc content measured by ICPMS.
• Demonstrated the probe's capability for real-time tracing of intracellular zinc during cell culturing.
• Quantified cellular uptake of Zn2+ in MCF-7 cells, observing a maximum uptake of 60.5 fg per cell at 60 min incubation.

Conclusions:

• The developed ratiometric probe enables accurate intracellular zinc quantification via fluorescence imaging.
• This approach offers a valuable tool for real-time monitoring of intracellular zinc in biological research and in vivo applications.