DNA nanosensor based on biocompatible graphene quantum dots and carbon nanotubes

• Specific fluorescence “on-off-on” process between GQDs-probe and CNTs is achieved.
• FRET between GQDs and CNTs was employed to achieve quantitative analysis of DNA.
• The nanosensor can identify DNA sequence with high sensitivity and selectivity.
• The nanosensor shows excellent performance in trace analysis of DNA.
• All the materials involved in the sensing system are of excellent biocompatibility.

An ultrasensitive nanosensor based on fluorescence resonance energy transfer (FRET) between biocompatible graphene quantum dots and carbon nanotubes for DNA detection was reported. We take advantage of good biocompatibility and strong fluorescence of graphene quantum dots, base pairing specificity of DNA and unique fluorescence resonance energy transfer between graphene quantum dots and carbon nanotubes to achieve the analysis of low concentrations of DNA. Graphene quantum dots with high quantum yield up to 0.20 were prepared and served as the fluorophore of DNA probe. FRET process between graphene quantum dots-labeled probe and oxidized carbon nanotubes is easily achieved due to their efficient self-assembly through specific π–π interaction. This nanosensor can distinguish complementary and mismatched nucleic acid sequences with high sensitivity and good reproducibility. The detection method based on this nanosensor possesses a broad linear span of up to 133.0 nM and ultralow detection limit of 0.4 nM. The constructed nanosensor is expected to be highly biocompatible because of all its components with excellent biocompatibility.