Molecular third-harmonic-generation microscopy through resonance enhancement with absorbing dye

Area of Science:

• Biophotonics
• Molecular Imaging
• Microscopy

Background:

• Three-dimensional (3D) molecular imaging is crucial for understanding cellular structures.
• Traditional fluorescence microscopy can suffer from photobleaching and background noise.
• Third-harmonic-generation (THG) microscopy offers label-free imaging capabilities.

Purpose of the Study:

• To develop a facile and effortless method for 3D molecular THG microscopy.
• To demonstrate resonance enhancement using an absorbing dye for improved contrast.
• To achieve selective enhancement of THG signals at specific cellular sites.

Main Methods:

• Utilized third-harmonic-generation (THG) microscopy.
• Employed resonance enhancement with an absorbing dye (hematoxylin).
• Used 1230 nm excitation light for multiphoton resonant enhancement.

Main Results:

• Achieved facile and effortless 3D molecular THG microscopy.
• Hematoxylin selectively enhanced THG yield at cell nuclear sites.
• Demonstrated the potential of hematoxylin as a cell nucleus contrast agent.

Conclusions:

• Combining THG microscopy with mature staining techniques enables 3D molecular imaging.
• Resonance enhancement with absorbing dyes provides a viable alternative to fluorescence imaging.
• This method offers a straightforward approach for high-contrast cellular imaging.