Water Models in Molecular Dynamics Simulation Prediction of Dielectric Properties of Biomaterials

To develop and reliably use diagnostic and therapeutic methods employing microwaves, we need to have an accurate knowledge of biological dielectric properties. Traditionally, dielectric properties of biosamples are determined experimentally. However, such measurements require dedicated hardware and physical availability of sufficient volume of biological samples of interest. Instead, here, we demonstrate the prediction of complex permittivity of a simple biomolecular sample using computational molecular dynamics simulations. We focus here on the role of a molecular model of water since it is the major compound determining microwave dielectric properties of biological tissues and wet samples. Here, for the first time, we analyze how the common molecular water models (SPC/E, TIP3P, and TIP4P) affect complex permittivity of biomolecular solutions predicted by molecular dynamics simulations. We found that the type of the molecular water model used in the simulation affects not only water contribution but also biomolecule contribution to the permittivity spectra. Our results contribute to in silico prediction and understanding of dielectric properties of biomaterials.