Label-Free Single Cell Viability Assay Using Laser Interference Microscopy.

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Label-free methods are crucial for real-time single-cell research.
• Assessing mammalian cell viability is essential in various biological studies.
• Existing methods may require cell labeling, impacting cellular processes.

Purpose of the Study:

• To develop a sensitive and reproducible method for cell viability assessment using Laser Interference Microscopy (LIM).
• To investigate phase thickness fluctuations in viable and non-viable MCF-7 cells.
• To establish quantitative parameters for distinguishing cell viability.

Main Methods:

• Utilized Laser Interference Microscopy (LIM) for real-time investigation of MCF-7 cells.
• Analyzed phase thickness fluctuations and their power spectrum slopes.
• Developed signal processing techniques to interpret fluctuation data.

Main Results:

• Identified variable 'v' (exceeding 20 nm² for viable attached cells) as an indicator of viability in attached cells.
• Determined critical power spectrum slope values (β=1.00 for attached, β=0.71 for suspended cells).
• The power spectrum slope (β) was found to be the most appropriate indicator of cell viability.

Conclusions:

• The power spectrum slope (β) of phase thickness fluctuations is a reliable indicator of cell viability.
• An integrated criterion using 'v' and 'β' can effectively assay viability in attached cells.
• LIM provides a promising label-free tool for quantitative cell viability assessment.