Atomistic modeling of hydration and antibiofouling of TMAO-polymer surfaces

Trimethylamine N-oxide (TMAO)-derived zwitterionic polymers have emerged as a next-generation sustainable material for avoiding biofouling on submerged surfaces in marine and biomedical applications. However, the underlying interactions between TMAO surfaces and proteins at the microscopic level remain unclear. We performed atomistic molecular dynamics simulations coupled with free-energy computations to provide insights into the hydration of TMAO-polymer brushes (pTMAO) and their interactions with proteins in pure and saline water. Our simulations show a condensed hydration water layer on the pTMAO surfaces, even in the presence of salt. The free energy calculations further quantify a smaller protein desorption energy for the pTMAO surfaces. However, their surface's hydration is strong enough to resist protein adsorption, upon creating an energy barrier, compared to other biofouling surfaces. Even the presence of salts has a negligible effect on their ability to resist protein adsorption. Our work thus provides a thorough understanding of hydration, protein adsorption, and anti-biofouling behavior of TMAO-derived polymer brushes.