Exploring the adsorption properties of doped phosphorene for the uptake of DNA nucleobases

Abstract

In pursuit of novel nanodevices for the manipulation of DNA constituents, layered phosphorene materials have emerged as promising candidates due to their excellent uptake properties, biocompatibility, and in vivo biodegradability. Here, a density functional theory (DFT) study is performed to explore the uptake of Watson–Crick DNA nucleobases onto metal/metalloid phosphorene nanoflakes (MPhos, M=Al, Si, Ti, Cu), providing microscopic insights to understand the molecular structure, adsorption stability, intermolecular forces, and effects on the electronic properties of the formed complexes in solution. Structural/stability analyses show that DNA nucleobases form stable complexes with doped-phosphorene by coordinate covalent bonding (chemisorption) in a mainly stacked adsorption pattern. Solvation effects considerably decrease the adsorption stability onto SiPhos, but (Al, Ti, Cu)Phos nanoflakes show adsorption energies higher than ~1 eV, acting as excellent uptake platforms of DNA biomolecules in solution. Binding and energy decomposition analyses (AIM, IGM, ALMO-EDA) reveal that the intermolecular forces (adsorption mechanism) are mainly driven by attractive electrostatic interactions (41–55%) and complemented with a balanced interplay between charge transfer, polarization, and dispersion driving forces. DNA nucleobases also act as n-dopants, inducing charge doping of the MPhos adsorbents. The latter cause considerable variations in the electronic structure of TiPhos and CuPhos nanoflakes, implying potential uses in the sensing of DNA constituents. Furthermore, electron-density and electron delocalization indexes reveal that the aromatic character of nucleobases is not affected upon chemisorption. These results provide an atomistic perspective on the potential use of doped-phosphorene materials for future adsorption, analysis, sensing, and/or resembling technologies of DNA constituents in solution.