Optical phase nanoscopy in red blood cells using low-coherence spectroscopy

Area of Science:

• Biomedical Optics
• Cellular Biophysics
• Medical Diagnostics

Background:

• Red blood cell (RBC) visco-elastic properties are crucial biomarkers for various diseases.
• Accurate, non-invasive methods are needed to monitor RBC health and disease progression.
• Current techniques may lack the sensitivity to detect subtle changes in RBC membrane dynamics.

Purpose of the Study:

• To introduce a novel low-coherence spectral-domain phase microscopy (SDPM) system.
• To enable accurate quantitative phase measurements of red blood cell (RBC) membrane fluctuations.
• To assess the potential of SDPM for disease prognosis and monitoring.

Main Methods:

• Developed and implemented a low-coherence spectral-domain phase microscopy (SDPM) system.
• Performed time-recordings of nano-scale cell membrane fluctuations in RBCs.
• Compared SDPM performance with wide-field digital interferometry (WFDI) for measuring low-amplitude fluctuations.

Main Results:

• SDPM accurately measured nano-scale fluctuations in RBC membranes.
• Glutaraldehyde-treated RBCs exhibited lower fluctuation amplitudes, indicating increased membrane stiffness.
• SDPM demonstrated superior optical-path-delay stability (<0.3 nm) compared to WFDI in liquid environments.

Conclusions:

• The SDPM system offers high accuracy and sensitivity for quantitative phase measurements of RBCs.
• The system's ability to detect changes in membrane stiffness holds promise for disease monitoring.
• SDPM's compact, robust, and inexpensive design makes it suitable for clinical applications.