Predicting biomolecule adsorption on MoS2 nanosheets with high structural fidelity

Abstract

A new force field, MoSu-CHARMM, for the description of bio-interfacial structures at the aqueous MoS₂ interface is developed, based on quantum chemical data. The force field describes non-covalent interactions between the MoS₂ surface and a wide range of chemistries including hydrocarbon, alcohol, aldehyde, ketone, carboxylic acid, amine, thiol, and amino acid groups. Density functional theory (DFT), using the vdW-DF2 functional, is employed to create training and validation datasets, comprising 330 DFT binding energies for 21 organic compounds. Development of MoSu-CHARMM is guided by two criteria: (i) minimisation of energetic differences compared to target DFT data and (ii) preservation of the DFT energetic rankings of the different binding configurations. Force-field performance is validated against existing high-quality structural experimental data regarding adsorption of four 26-residue peptides at the aqueous MoS₂ interface. Adsorption free energies for all twenty amino acids in liquid water are calculated to provide guidance for future peptide design, and interpret the properties of existing experimentally-identified MoS₂-binding peptides. This force field will enable large-scale simulations of biological interactions with MoS₂ surfaces in aqueous media where an emphasis on structural fidelity is prioritised.