Reactive Molecular Dynamics Simulation on Plasma-induced Destruction of Fungal Cell Wall Components

Low-temperature atmospheric pressure plasmas are causing great attention for biomedical applications, the reactive species of which have been proven to be of great importance. However, there is very little basic research on the interaction mechanisms between the reactive species and biological components up to now. Simulating at the atomic level may be effective for acquiring a better insight in these processes. In this paper, reactive molecular dynamics simulations method is introduced to model the interaction of important reactive oxygen species, such as OH, O2 and O, with fungal chitin for a better understanding of plasma sterilization. It is found that among the reactive oxygen species mentioned above, OH radical and O atom can fracture important bonds of chitin (i.e., C-O, C-N, C-C), which subsequently results in the destruction of the fungal cell wall. All bond cleavages detected in the processes are initiated by a hydrogen-abstraction reaction from the chitin. Moreover, the OH radicals can react with each other and reduce the damage efficiency to the structure. It should also be mentioned that there is no bond cleavage events observed in the case of O2 molecules, which have only weak attractive non-bond interactions with the chitin. The simulation results are in good agreement with relevant experimental conclusions. This study can provide an important reference value for nonreversible destruction of the fungal chitin structure at the atomic level.