Synthesis of Nanographene-DNA Conjugates and Their Profiling with MoS2 Nanopores.

We demonstrate the possibility of covalently bonded hybrid DNA-graphene materials by synthesizing a model DNA-polycyclic aromatic hydrocarbon (PAH) conjugate comprising a 33mer oligonucleotide containing thymine and uridine modified with bispyrenyl benzene. This DNA-PAH conjugate (T13UPAHT19; T = thymine, UPAH = PAH-modified uridine) has an atomically thin nanographene protrusion extending by only about 1 nm from the single-stranded DNA (ssDNA). We show that DNA-PAH conjugates can be characterized with high resolution by profiling with a nanopore in a monolayer MoS2 membrane. The profiling experiments provided sufficient resolution to distinguish the thymine and PAH-modified regions of T13UPAHT19 and confirm the asymmetry of the PAH attachment relative to the 3' and 5' ends of the ssDNA due to different lengths of the T13 and T19 segments. This work provides the foundation for further exploration of DNA-graphene hybrids, demonstrating an example of their synthesis and the utility of nanopore profiling for their structural characterization with an ∼1 nm resolution.