Label-free visualization and quantification of single cell signaling activity using metal-clad waveguide (MCWG)-based...

Area of Science:

• Biophysics
• Cell Biology
• Biosensing Technology

Background:

• Label-free biosensing is crucial for studying cell signaling but often assumes homogeneous cell responses.
• Evidence suggests significant cell-to-cell variability even in genetically identical populations.
• Traditional assays averaging signals may obscure individual cell behavior.

Purpose of the Study:

• To demonstrate metal-clad waveguide (MCWG)-based microscopy for label-free, real-time monitoring of individual cell signaling and morphology.
• To quantify apoptosis in individual cells and assess endothelial cell layer integrity.
• To highlight the limitations of population-averaged data in cell-based assays.

Main Methods:

• Utilized metal-clad waveguide (MCWG)-based microscopy for label-free, real-time imaging.
• Monitored intracellular activity during apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).
• Visualized and quantified extracellular changes in endothelial cell layer integrity upon proteinase-activated receptor 1 (PAR1) activation by thrombin.

Main Results:

• MCWG microscopy successfully resolved and monitored individual cell responses in real-time.
• Quantified apoptosis-induced intracellular activity and extracellular layer integrity changes at the single-cell level.
• Demonstrated that population-averaged signals can significantly misrepresent individual cell morphology and kinetics.

Conclusions:

• Label-free MCWG microscopy enables precise monitoring of individual cell behavior, overcoming limitations of population-based assays.
• Cellular heterogeneity is significant and must be considered in biosensing and signaling studies.
• This technique offers a powerful tool for understanding cell responses with high resolution.