Graphene Fluorescence Resonance Energy Transfer Aptasensor for the Thrombin Detection

TLDR

Combining nanomaterials and biomolecule recognition units is promising for novel clinical diagnostics and protein analysis. The study develops a highly sensitive and specific FRET aptasensor for thrombin detection using a dye‑labeled aptamer assembled on graphene. The sensor relies on noncovalent aptamer–graphene assembly that quenches dye fluorescence via FRET, and thrombin binding restores fluorescence by forming quadruplex–thrombin complexes that detach the dye from graphene. The graphene FRET aptasensor achieves extraordinary sensitivity and specificity, detecting thrombin down to 31.3 pM—two orders of magnitude lower than carbon‑nanotube sensors—thanks to graphene’s high quenching efficiency and unique electronic properties.

Abstract

Combining nanomaterials and biomolecule recognition units is promising in developing novel clinic diagnostic and protein analysis techniques. In this work, a highly sensitive and specific fluorescence resonance energy transfer (FRET) aptasensor for thrombin detection is developed based on the dye labeled aptamer assembled graphene. Due to the noncovalent assembly between aptamer and graphene, fluorescence quenching of the dye takes place because of FRET. The addition of thrombin leads to the fluorescence recovery due to the formation of quadruplex−thrombin complexes which have weak affinity to graphene and keep the dyes away from graphene surface. Because of the high fluorescence quenching efficiency, unique structure, and electronic properties of graphene, the graphene aptasensor exhibits extraordinarily high sensitivity and excellent specificity in both buffer and blood serum. A detection limit as low as 31.3 pM is obtained based on the graphene FRET aptasensor, which is two orders magnitude lower than those of fluorescent sensors based on carbon nanotubes. The excellent performance of FRET aptasensor based on graphene will also be ascribed to the unique structure and electronic properties of graphene.