Lysozyme orientation and conformation on MoS

Two-dimensional molybdenum disulfide (MoS2) has attracted intense interest owing to its unique properties and promising biosensor applications. To develop effective biocompatible platforms, it is crucial to understand the interactions between MoS2 and biological molecules such as proteins, but little knowledge exists on the orientation and conformation of proteins on the MoS2 surface at the molecular level. In this work, the lysozyme adsorption on the MoS2 surface was studied by molecular dynamics simulations, wherein six different orientations were selected based on the different faces of lysozyme. Simulation results showed that lysozyme tends to adsorb on the MoS2 surface in an "end-on" orientation, indicating that orientations within this range are favorable for stable adsorption. The end-on orientation could be further categorized into "bottom end-on" and "top end-on" orientations. The driving forces responsible for the adsorption were dominated by van der Waals interactions and supplemented by electrostatic interactions. Further, the conformations of the lysozyme adsorbed on the MoS2 surface were basically preserved. This simulation study promotes the fundamental understanding of interactions between MoS2 and proteins and can guide the development of future biomedical applications of MoS2.