Quantum-yield-optimized fluorophores for site-specific labeling and super-resolution imaging

Area of Science:

• Biochemistry and Molecular Biology
• Microscopy and Imaging Technologies
• Chemical Biology

Background:

• Advanced microscopy techniques like STED microscopy require highly fluorescent and photostable dyes.
• Existing fluorophores often have limitations in brightness and stability for demanding single-molecule applications.
• Site-specific labeling of proteins is crucial for studying biological processes in vivo.

Purpose of the Study:

• To synthesize and characterize novel, quantum-yield-optimized fluorophores for reversible, site-specific protein labeling.
• To enhance fluorescence signals using rigid polyproline-II (PPII) helices as spacers.
• To demonstrate the utility of these new fluorophores in super-resolution microscopy of neuronal structures.

Main Methods:

• Synthesis of trisNTA-fluorophores with varying lengths of polyproline-II (PPII) spacers.
• Characterization of fluorophore properties using steady-state and fluorescence lifetime analyses.
• In vivo protein labeling and imaging of His-tagged AMPA receptors (GluA1) in living neurons using confocal and STED microscopy.

Main Results:

• Demonstrated improved quantum yields and fluorescence signals of trisNTA-PPII-fluorophores.
• Successfully achieved in vivo labeling and super-resolution imaging of synaptic proteins.
• STED microscopy revealed superior resolution compared to confocal microscopy for synaptic cleft imaging.

Conclusions:

• Developed small, biocompatible, and photostable trisNTA-PPII-fluorophores.
• These novel fluorophores significantly enhance performance in super-resolution microscopy.
• The findings offer advantages for imaging biological structures at the nanoscale.