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 (T₁₃U_PAHT₁₉; T = thymine, U_PAH = 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 T₁₃U_PAHT₁₉ 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.