Membrane Insertion of MoS₂ Nanosheets: Fresh vs. Aged

Fresh two-dimensional molybdenum disulfide (MoS₂) absorbs the hydrocarbon contaminations in the ambient air and makes surface aging. To understand how the surface aging influences the interactions between MoS₂ and biomolecules is important in the biomedical applications. Here, employing all-atom molecular dynamics simulations, we investigated the interactions of the fresh and aged MoS₂ nanosheets with the lipid membranes of different components. Our results demonstrate that both the fresh and aged MoS₂ nanosheets can spontaneously insert into the bilayer membranes. However, the fresh MoS₂ nanosheet displays significantly stronger interaction and then has a larger penetration depth than the aged counterpart, regardless of the lipid components. The calculations of potential mean forces through the umbrella sampling further confirm that the insertion of fresh MoS₂ into the lipid membranes is more energetically favorable. Moreover, we found that the fresh MoS₂ nanosheet can cause a larger damage to the integrity of lipid membranes than the aged one. This work provides insightful understandings of the surface-aging-dependent interactions of the MoS₂ nanosheets with biomembranes, which could facilitate the design of novel MoS₂-based nanodevices with advanced surface properties.