Nonlinear optical imaging of extracellular matrix proteins

Area of Science:

• Biomedical Optics
• Microscopy Techniques
• Tissue Imaging

Background:

• Nonlinear imaging methods, including multiharmonic imaging microscopy (MHIM), are crucial for label-free biological structure visualization.
• MHIM generates signals from molecular orientation and physical properties, complementing techniques like two-photon excitation (TPE).

Purpose of the Study:

• To present a methodology for integrated multiharmonic and TPE imaging of the mouse aorta.
• To demonstrate label-free differentiation of collagen fibrils and elastic laminae in the mouse aorta.

Main Methods:

• Implementation of an integrated multiharmonic and TPE imaging approach using a commercial two-photon microscope.
• Utilizing 820nm and 1230nm excitation wavelengths for imaging.
• Performing multiharmonic generation via reflectance of the forwardly propagating emission signal.

Main Results:

• Successful differentiation of mouse aorta microstructure, specifically collagen fibrils and elastic laminae.
• Demonstration of label-free visualization capabilities of the integrated imaging approach.

Conclusions:

• The integrated multiharmonic and TPE imaging method effectively visualizes mouse aorta microstructure without stains.
• This technique has potential applications for studying other collagen and elastin-rich tissues.