Video-rate two-photon microendoscopy using second harmonic resonance fiber scanning.

Area of Science:

• Biomedical Optics
• Microscopy Engineering
• Medical Imaging Technology

Background:

• Traditional microendoscopy often suffers from motion artifacts, limiting real-time in vivo imaging.
• Existing fiber scanning techniques have limitations in frame rate, hindering dynamic tissue observation.

Purpose of the Study:

• To develop a high-frame-rate, hand-held two-photon microendoscope for artifact-free tissue imaging.
• To enhance fiber scanning methods for improved imaging speed without compromising resolution.

Main Methods:

• A 2.5-mm resonant fiber scanning two-photon microendoscope with a 30-mm rigid probe was designed.
• Higher-order harmonic oscillation scanning techniques were implemented to achieve video-rate imaging (20 Hz).
• 3D printed mounts were utilized for cost-effective and stable fabrication of the fiber scanner.

Main Results:

• The microendoscope achieved a 20 Hz frame rate, significantly faster than previous designs.
• Maintained field-of-view (~125 µm) and optical resolution (1.2 µm lateral, 10.9 µm axial).
• Demonstrated high stability (<0.3 µm drift over 84 hours) with cost-effective 3D printed components.

Conclusions:

• The developed microendoscope enables real-time, hand-held imaging of tissues with reduced motion artifacts.
• This technology advances multiphoton microendoscopy for in vivo applications.
• The use of higher-order harmonic scanning and 3D printing offers a practical solution for high-performance microendoscopy.