Real-time four-dimensional optical-resolution photoacoustic microscopy with Au nanoparticle-assisted...

Area of Science:

• Biomedical optics
• Microscopy
• Medical imaging

Background:

• Photoacoustic microscopy (PAM) provides label-free imaging based on optical absorption.
• High-resolution imaging is crucial for visualizing microcirculation dynamics.

Purpose of the Study:

• To develop and demonstrate a high-speed, high-resolution photoacoustic microscopy system.
• To achieve four-dimensional (4D) in vivo imaging of microcirculation in mouse skin.

Main Methods:

• An inverted microscope configuration was used with a 100 kHz laser pulse repetition rate.
• A stationary ultrasonic transducer and 2D raster scanning enabled high-speed data acquisition.
• The system achieved a 2D B-scan frame rate of 1800 Hz and an A-scan rate of 90,000 Hz.

Main Results:

• Four-dimensional in vivo imaging of mouse skin microcirculation was performed at 18 3D volumes per second.
• The system achieved a lateral resolution of 0.23 ± 0.03 microm for gold nanowire imaging.
• This resolution is 2.0 times below the optical diffraction limit.

Conclusions:

• The developed high-speed PAM system enables rapid, label-free 4D microcirculation imaging.
• Sub-diffraction-limit resolution is achievable with this advanced PAM technology.
• This system holds potential for in vivo studies of dynamic biological processes.