Imaging live cells grown on a three dimensional collagen matrix using Raman microspectroscopy

Area of Science:

• Biophysics
• Cell Biology
• Spectroscopy

Background:

• Live-cell imaging is crucial for understanding cellular dynamics.
• Raman spectroscopy offers label-free biochemical information.
• 3D cell culture models mimic in vivo environments.

Purpose of the Study:

• To develop and validate a Raman spectroscopy system for live-cell imaging within 3D collagen matrices.
• To investigate the subcellular molecular composition of human lung adenocarcinoma (A549) and keratinocyte (HaCaT) cell lines.

Main Methods:

• Utilized a Raman spectroscopy setup with <1.5 μm lateral resolution.
• Employed K-means clustering for subcellular compartment identification.
• Applied principal component analysis (PCA) to enhance spectral data and identify key molecular variations.

Main Results:

• Successfully imaged live A549 and HaCaT cells within 3D collagen gels.
• Differentiated subcellular compartments (e.g., nucleus, cytoplasm) using K-means clustering.
• Identified distinct molecular signatures for different cellular structures through spectral analysis and PCA, correlating spectral variations with biochemical content.

Conclusions:

• 3D collagen gels are suitable matrices for high-resolution live-cell Raman spectroscopy.
• Raman spectroscopy, enhanced by clustering and PCA, can visualize subcellular biochemical heterogeneity.
• This technique provides a powerful tool for label-free molecular interrogation of live cells in a 3D context.