A Mitochondria-Targeted Ratiometric and Colorimetric Fluorescent Probe for Hg²⁺ Based on...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Cell Biology

Background:

• Accurate detection of mercury ions (Hg²⁺) is crucial due to their toxicity.
• Developing selective and sensitive probes for biological applications remains a challenge.
• Mitochondria are key organelles affected by heavy metal ions.

Purpose of the Study:

• To develop the first mitochondria-targeted ratiometric and colorimetric fluorescent probe for Hg²⁺ detection.
• To enable sensitive and selective imaging of intracellular Hg²⁺ fluctuations.
• To explore a novel design strategy for fluorescent probes.

Main Methods:

• Synthesis of a fluorescent probe (1) using coumarin, diphenylphosphinoselenoate, and a p-hydroxybenzyl moiety.
• Spectroscopic analysis (absorption and fluorescence) to characterize probe response to Hg²⁺.
• Cellular imaging experiments to assess mitochondria targeting and intracellular Hg²⁺ detection.

Main Results:

• Probe 1 exhibited a significant blue shift in absorption (492 to 426 nm) and fluorescence (570 to 498 nm) upon Hg²⁺ binding.
• A dramatic increase in emission ratio (F_498nm/F_570nm, up to 892-fold) and visible color changes were observed.
• The probe demonstrated high sensitivity (detection limit 16.7 nM), selectivity for Hg²⁺, and successful mitochondria targeting for intracellular Hg²⁺ imaging.

Conclusions:

• The developed probe is the first mitochondria-targeted ratiometric and colorimetric sensor for Hg²⁺.
• The probe enables sensitive, selective, and visual detection of Hg²⁺, with potential for monitoring intracellular metal ion dynamics.
• The novel design strategy offers a new avenue for developing advanced fluorescent probes.