Nanoscale Chemical Imaging of Human Cell Membranes Using Tip-Enhanced Raman Spectroscopy.

Area of Science:

• Biophysics
• Cell Biology
• Spectroscopy

Background:

• Understanding cell membrane organization at the nanoscale is crucial for deciphering cellular functions.
• Existing visualization tools often lack the required resolution or necessitate invasive labeling, limiting insights into native membrane structures.

Purpose of the Study:

• To develop and apply a non-invasive, label-free nanoscale imaging technique for visualizing molecular distributions in pancreatic cancer cell membranes.
• To investigate the nanoscale organization and composition of BxPC-3 cell membrane domains.

Main Methods:

• Utilized tip-enhanced Raman spectroscopy (TERS) for high-resolution imaging of cell membranes under ambient conditions.
• Achieved spatial resolution down to approximately 2.5 nanometers without the need for molecular labels.

Main Results:

• TERS imaging revealed nanoscale segregation of molecular domains rich in phenylalanine, histidine, phosphatidylcholine, protein, and cholesterol within BxPC-3 cell membranes.
• Observed regions where cholesterol and protein were co-localized.
• Demonstrated that nanoscale molecular domains are not chemically pure, containing mixtures of various biomolecules.

Conclusions:

• Tip-enhanced Raman spectroscopy is a powerful tool for label-free, non-destructive imaging of cell membranes with nanoscale precision.
• The findings provide novel insights into the complex molecular organization of pancreatic cancer cell membranes.