Analysis of Nano-Bio Interfaces with Multi-Scale Molecular Simulations

I’ll discuss our recent analyses of nano-bio interfaces with multi-scale molecular simulations. In particular, we will discuss the integration of coarse-gained and atomistic molecular dynamics simulations to analyze how nano-sized plastic particles (nanoplastics), which originate from the breakdown of microplastics, drive changes in the membrane structure and dynamics. Using uncrosslinked polystyrene nanoparticles as a model for nanoplastic particles, Laurdan fluorescence spectroscopy experiments have observed a concentration dependent blue shift that would typically be interpreted as a fluid to gel membrane phase transition for traditional nano-bio interactions. Our molecular simulations suggested instead that the flexible, hydrophobic nature, of polystyrene nanoparticles allows them to penetrate and dissolve into the membrane interior leading to a dehydration of Laurdan probe molecules that confounds traditional interpretation of Laurdan fluorescence. We then discuss the use of non-linear spectroscopies to further probe the mechanism at the molecular scale. Some of the computational approaches we develop might be applicable to the mechanistic analysis of nanoparticle assembly as well.