Stiff-FCS: Single-Cell Stiffness Profiling With Integrated Molecular and Functional Analysis.

Area of Science:

• Biophysics
• Cell Biology
• Microfluidics

Background:

• Cell stiffness influences cell deformation, migration, and adaptation to mechanical environments.
• Existing single-cell stiffness assays lack integration with molecular analysis and functional studies.

Purpose of the Study:

• Introduce a microfluidic platform, stiffness-based ferrohydrodynamic cell sorting (Stiff-FCS), for high-throughput single-cell stiffness quantification.
• Enable on-chip molecular analysis and post-assay cell recovery for comprehensive cell characterization.
• Link single-cell stiffness to molecular heterogeneity and cell behavior.

Main Methods:

• Utilize ferrofluid-driven actuation and graded confinement channels for cell sorting based on stiffness.
• Employ an inverse computational model to derive quantitative Young's modulus from cell position and morphology.
• Perform same-cell fluorescence-based protein analysis and cell recovery for downstream assays.

Main Results:

• Demonstrate stiffness profiling of thousands of cells within minutes.
• Identify Lamin A/C as consistently associated with cell stiffness across diverse cell lines.
• Observe that softer cells exhibit greater migratory capacity than stiffer cells.
• Resolve a stiff, less migratory subpopulation in cancer cells with a higher-molecular-weight Vimentin state.

Conclusions:

• Stiff-FCS provides a workflow for linking single-cell stiffness to molecular states and cell behavior.
• Cell stiffness is a critical factor in cell migration and can be modulated by molecular factors like Vimentin.
• The platform facilitates deeper understanding of cell mechanics in health and disease.