A Hybrid Molecule/Graphene van der Waals Heterostructure for DNA Immobilization and Detection

Graphene-based field-effect biosensors have attracted intensive interest due to the potential for realizing highly sensitive, selective, rapid, and multiplexed detection. To fabricate such a biosensor, graphene needs to be functionalized with a linker layer, to bridge the graphene channel with a biomolecular probe. This step is usually cumbersome and has limited material options. Given the advantages of graphene to seamlessly integrate with solution-processable organic molecules to form a hybrid van der Waals heterostructure, it is desirable to simplify and implement ways of generalizing the functionalization process. Herein, a diazirine-based molecule that self-assembles on graphene is reported to behave as a photoreactive anchoring layer to conveniently immobilize biomolecular probes, such as single-stranded DNA (ssDNA). The prototype sensor can hierarchically detect two "analyte" ssDNAs that are complementary to different regions of the immobilized nucleic acid within 15 min, with a sensitivity of 14 mV/decade and a dynamic range spanning over 9 orders of magnitude.