Trace Cu²⁺-Catalyzed Oxidative Fluorogenic Assay for Dopamine Imaging in Living Cells

Area of Science:

• Neuroscience
• Analytical Chemistry
• Biochemistry

Background:

• Dopamine (DA) is a critical neurotransmitter involved in numerous neurological functions and disorders.
• Real-time visualization of DA in cells is difficult due to limitations in current sensing technologies.
• Understanding DA dynamics is crucial for neurological research.

Purpose of the Study:

• To develop a novel, biocompatible, and high-fidelity sensing strategy for real-time dopamine imaging in living cells.
• To overcome the limitations of existing oxidant-dependent methods for DA detection.
• To investigate the role of DA in cellular states, including normal, inflammatory, and depressive conditions.

Main Methods:

• Developed a trace copper(II)-catalyzed oxidative fluorogenic assay for dopamine detection.
• Utilized a copper-mediated redox cycle to catalyze DA oxidation.
• Employed 8-hydroxyjulolidine for specific fluorogenic recognition of oxidized DA.
• Performed time-lapse imaging in PC12 cells under various conditions.

Main Results:

• The assay provides a robust fluorescence response at 510 nm with high sensitivity and selectivity for DA.
• Successfully detected endogenous DA dynamics in PC12 cells under normal, inflammatory, and depressive conditions.
• Observed suppressed DA release and altered DA reuptake kinetics in depressive cell models.

Conclusions:

• The novel assay is a powerful tool for selective, real-time imaging of dopamine in living cells.
• This method facilitates the elucidation of dopamine's complex roles in neural systems under physiological and pathological states.
• The findings offer new insights into dopamine dysregulation in neurological disorders like depression.