(619f) Spin-Polarized Calculations of Hydrated Magnetite Surfaces: Implications for Biomedical Applications

Magnetite (Fe₃O₄) is a commonly used material for biomedical applications, such as bioseparations, drug delivery and diagnostics, including magnetic resonance imaging. In each of these cases, the magnetite-water interface is expected to play a key role in controlling surface chemistry and reactivity, yet the structure of this interface remains elusive. In this study, the surface structure and energetics of both clean and hydrated Fe₃O₄ (1 0 0) and Fe₃O₄ (1 1 1) are calculated using spin-polarized density functional theory and are compared with experimental characterizations. The energetics of the clean (1 0 0) surface are measured against the (1 1 1) surface in order to obtain a fundamental understanding of water ordering at the interface. Water is both molecularly adsorbed and heterolytically dissociated on the two surfaces, and the energetics of these hydrated surfaces are examined. The implications of water ordering at magnetite surfaces will be discussed in the context of surface reactivity for the aforementioned biomedical applications.