Local-flexible coupling optical-resolution photoacoustic microscopy with enhanced sensitivity

Area of Science:

• Biomedical Engineering
• Optical Imaging
• Acoustic Physics

Background:

• Acoustic coupling is critical for optical-resolution photoacoustic microscopy (OR-PAM) performance.
• Existing coupling methods can limit practicability, sensitivity, and stability.

Purpose of the Study:

• To develop and evaluate a local-flexible acoustic coupling scheme for OR-PAM.
• To enhance OR-PAM sensitivity and imaging capabilities for biomedical applications.

Main Methods:

• Designed a combiner integrating an objective lens and transducer with water level control and bubble drainage.
• Implemented a circulating system for sustained, steady water flow.
• Constrained flowing water to create a stable, local acoustic coupling between sample and transducer.

Main Results:

• Phantom experiments showed a 1.9-fold increase in detection sensitivity compared to dry coupling, maintaining high optical resolution.
• In vivo imaging of mouse eyegrounds demonstrated improved visualization of microvasculature details.
• The system proved practical for biomedical imaging.

Conclusions:

• The local-flexible acoustic coupling scheme significantly enhances OR-PAM sensitivity and stability.
• This improved OR-PAM offers greater detail in biomedical imaging, especially for microvasculatures.
• The proposed method shows potential for broad applications in biomedical fields.