Single-Cell Analysis with Silver-Coated Pipette by Combined SERS and SICM

Area of Science:

• Nanotechnology
• Cell Biology
• Spectroscopy

Background:

• Investigating intracellular and cell surface processes is crucial for medical drug development, cytology, and cell technologies.
• Existing methods often have limitations in analyzing living cells non-invasively.
• A need exists for integrated techniques enabling simultaneous topographical and molecular analysis of cells.

Purpose of the Study:

• To develop and demonstrate an original silver-coated pipette for combined surface-enhanced Raman spectroscopy (SERS) and scanning ion-conducting microscopy (SICM) cell analysis.
• To enable detailed molecular composition analysis of living cells, including cytoplasm and nucleus.
• To evaluate the performance and enhancement factor of the SERS-active pipette.

Main Methods:

• Fabrication of a silver-coated pipette using vacuum-thermal evaporation and annealing to create SERS-active nanoparticles.
• Utilizing scanning ion-conducting microscopy (SICM) for cell surface topography and mechanical property evaluation.
• Employing surface-enhanced Raman spectroscopy (SERS) with the pipette for molecular analysis of intracellular components.
• Characterizing nanoparticle morphology and calculating the theoretical enhancement factor using a two-particle model.

Main Results:

• Successfully fabricated SERS-active silver nanoparticles on the pipette with a diameter of ~36 nm and spacing of 12 nm.
• Achieved an enhancement factor (EF) of 7 × 10^5 for the SERS-active pipette.
• Demonstrated simultaneous SICM analysis and SERS molecular profiling of cytoplasm and nucleus in HEK-293 cancer cells.
• Confirmed successful probe localization within living cells.

Conclusions:

• The developed silver-coated pipette is an effective tool for integrated SICM and SERS analysis of living cells.
• This technique allows for detailed molecular mapping of cellular components, advancing cell biology research.
• The method holds promise for applications in drug discovery and diagnostics requiring high-resolution cellular analysis.