Viewing the Interaction Between Double Strand Deoxyribonucleic Acid and Graphene Oxide via Atomic Force Microscopy

Area of Science:

• Biomaterials Science
• Nanotechnology
• Molecular Biology

Background:

• The interaction between DNA and graphene-oxide (GO) is crucial for various biomedical applications.
• While the strong interaction between single-stranded DNA (ssDNA) and GO via π-π stacking is understood, the weaker interaction between double-stranded DNA (dsDNA) and GO is less clear.
• Understanding dsDNA-GO interactions is essential for developing novel biosensors and drug delivery systems.

Purpose of the Study:

• To investigate the coupling behavior and adsorption mechanisms of double-stranded DNA (dsDNA) on graphene-oxide (GO) surfaces.
• To elucidate the structural implications of dsDNA binding on GO sheets.
• To explore the stability of dsDNA-GO complexes under different conditions.

Main Methods:

• Atomic Force Microscopy (AFM) was employed to visualize and analyze the interaction between dsDNA and GO at the nanoscale.
• Controlled experimental conditions were used to observe adsorption preferences and structural formations.
• Stability tests involving rinsing and heating were performed on the resulting dsDNA-GO structures.

Main Results:

• AFM imaging revealed a preferential adsorption of dsDNA onto the GO surface.
• dsDNA molecules were observed to aggregate on the GO, forming distinct patterns.
• GO sheets were found to stack into multi-layer structures facilitated by dsDNA, indicating simultaneous interaction with both sides of the GO sheet.
• These dsDNA-induced multi-layer GO structures were found to be unstable, collapsing upon rinsing or heating.

Conclusions:

• dsDNA exhibits a tendency to aggregate on GO surfaces, driven by specific interaction mechanisms.
• dsDNA can mediate the formation of unstable multi-layer GO structures, suggesting a role in GO assembly.
• The observed instability of these structures highlights the dynamic nature of dsDNA-GO interactions and has implications for their application in responsive biomaterials.