Intercalation of DNA Nucleobases inside Bilayer Graphene and Bilayer MoS₂: A Comparative DFT Study

Abstract

The detection and discrimination of DNA bases (adenine, guanine, cytosine, and thymine) are foundational to genomics, diagnostics, and biotechnology. Two-dimensional (2D) layered materials, particularly bilayer graphene (BLG) and bilayer molybdenum disulfide (BLMoS 2 ), offer unique advantages for label-free DNA sensing due to their high surface sensitivity, tunable electronic properties, and ability to interact with biomolecules via non-covalent forces. In this study, we present a systematic density functional theory (DFT) investigation of the interaction between DNA bases and BLG/ BLMoS 2 , leveraging intercalation energy calculations, electronic band structure analysis, and topological bonding characterization. Results reveal that BLMoS 2 exhibits stronger intercalation energies with DNA bases (-1.00 to -1.02 eV) compared to BLG (-0.82 to -1.10 eV), driven by sulfur-mediated interactions alongside π-π stacking. Electronic band structure analysis shows significant band gap modulation in BLMoS₂ upon base intercalation, with shifts up to 0.5 eV, whereas BLG displays more subtle changes due to its semi-metallic nature.Topological analysis confirms non-covalent bonding in both systems, with BLMoS 2 showing higher electron density at bond critical points, indicating stronger intermolecular coupling. These findings highlight BLMoS₂ as a superior candidate for high-sensitivity DNA base detection, with implications for next-generation biosensors and DNA sequencing technologies.