Nanoscale visualization of extracellular DNA on cell surfaces

Area of Science:

• Biophysics
• Cell Biology
• Forensic Science

Background:

• Extracellular DNA (eDNA) on cell surfaces is relevant to DNA transfer and forensic investigations.
• Bulk analysis methods lack nanoscale spatial and temporal resolution for eDNA dynamics.
• 3D visualization of surface-associated eDNA offers unique insights into cellular interactions.

Purpose of the Study:

• To develop and demonstrate integrated microscopy techniques for nanoscale visualization of surface-associated eDNA.
• To analyze the distribution and characteristics of eDNA at the single-cell level.
• To explore the potential of these methods for forensic and biological trace sample analysis.

Main Methods:

• Integration of Atomic Force Microscopy (AFM) with optical microscopy.
• Fluorescence microscopy using Diamond™ Dye for eDNA visualization and quantification.
• Overlaying fluorescence data with AFM-derived surface topography and cellular elasticity.
• Chemical Force Spectroscopy for molecular-level eDNA distribution analysis.

Main Results:

• Successful visualization of surface-associated eDNA distribution at the single-cell level.
• Quantification of eDNA using fluorescence microscopy.
• Combined AFM and fluorescence microscopy provided structural and spatial eDNA information.
• Chemical force spectroscopy revealed molecular-level distribution of surface eDNA.

Conclusions:

• Integrated AFM and optical microscopy techniques enable nanoscale visualization of surface-associated eDNA.
• These methods enhance the understanding of eDNA's biological role and dynamics.
• The approach is valuable for analyzing challenging trace biological samples with limited cellular material.