Amplitude and phase images of cellular structures with a scanning surface plasmon microscope

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Achieving nanometer-scale axial resolution in non-invasive cellular imaging remains a significant challenge.
• Existing fluorescence microscopy often requires staining, which can alter biological samples.

Purpose of the Study:

• To introduce the Scanning Surface Plasmon Microscope (SSPM) as a complementary technique to fluorescence microscopy.
• To demonstrate the capability of SSPM for high-resolution, label-free imaging of cellular internal structures.

Main Methods:

• Utilizing surface plasmon resonance for evanescent field enhancement.
• Employing a Scanning Surface Plasmon Microscope (SSPM) for amplitude and phase imaging.
• Imaging fibroblast cells (IMR90) to assess imaging performance.

Main Results:

• SSPM provides very high resolution in the Z-scanning axis (normal to the sample).
• The technique offers enhanced detection of refractive index gradient regions within cells.
• SSPM successfully visualized subcellular structures like cell compartments, nucleus, nucleoli, and membranes.

Conclusions:

• SSPM is a valuable, non-invasive tool for high-resolution cellular imaging without the need for staining.
• The ability to discriminate regions of variable density makes SSPM well-suited for detailed biological sample analysis.