In-depth electronic behavior of pentagraphene and pentagonal silicene sheets for DNA nucleobase detection: implications for genetic biomarker sensing

Abstract

Silicon-based chemical sensors are optimal for detecting biological entities due to their fast response, biocompatibility, and non-invasive nature. In this work, we proposed pristine and metal [gold (Au) and tungsten (W)]-doped pentagonal silicene (p-Si) and pentagraphene (PG) as materials for single DNA nucleobase sensors. Using first-principles calculations, we presented a comparative study of DNA nucleobases—adenine (A), guanine (G), cytosine (C), and thymine (T)—adsorbed on pristine and metal-doped PG and p-Si to determine their potential as nucleobase detectors or for detecting other chemical species. The calculated binding affinities on the PG and p-Si surfaces using the M062X/6-31G* level of theory and adsorption energies from DFT predicted higher sensitivity of PG towards DNA nucleobases compared to p-Si, with evident changes in their work function and band structure properties. In the later section, we showed that doping with Au and W significantly enhanced the sensitivity of both PG and p-Si towards DNA nucleobases, as evidenced by their electronic band structures and PDOS calculations. The significant changes in the electronic properties of PG and p-Si upon adsorption of nucleobases make them promising candidates for rapid sensing, sequencing, and identification of DNA nucleobase elements. This study provides new insights into the physical and chemical interactions between biomolecules and PG/p-Si, highlighting their potential as templates for nanobiological devices. Both Au and W doping enhanced the adsorption properties, suggesting that PG and p-Si could be effectively used for biomolecule sensing applications.