Graphene quantum dots mediated electron transfer in DNA base pairs

Area of Science:

• Nanotechnology
• Biochemistry
• Electrochemistry

Background:

• Graphene quantum dots (GQDs) offer unique electronic and optical properties.
• Sensing DNA-mediated charge transfer is crucial for molecular electronics.
• Ruthenium complexes like [Ru(bpy)3]2+ are often used as signal probes.

Purpose of the Study:

• To investigate the interaction between GQD-functionalized ruthenium complexes ([Ru(bpy)3-GQD]2+) and abasic site double-stranded DNA (Abasic-DNA).
• To evaluate the effect of GQD intercalation on DNA-mediated charge transfer.
• To explore the potential of this structure for developing molecular devices.

Main Methods:

• Absorption spectroscopy
• Gel electrophoresis
• Circular dichroism
• Melting temperature measurements
• Electrochemical and electrochemiluminescence measurements
• Immobilization of DNA on gold electrodes via Au-S bonds

Main Results:

• [Ru(bpy)3-GQD]2+ intercalates into double-stranded DNA.
• GQDs act as base analogs, intercalating into the DNA duplex.
• [Ru(bpy)3-GQD]2+ enhances DNA-mediated charge transfer when intercalated into abasic sites.
• The GQD-DNA structure shows improved charge transfer compared to [Ru(bpy)3]2+ alone.

Conclusions:

• Graphene quantum dots can effectively intercalate into DNA, acting as base analogs.
• This intercalation significantly enhances DNA-mediated charge transfer.
• The DNA-GQD structure holds promise for advancing molecular devices and broadening DNA charge transfer applications.