biophysical chemistry and spectroscopy group

Hore group

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The conformation of proteins is well-recognized as being of paramount importance to their function in living systems and synthetic bio-devices. We are interested in the interaction of proteins with hydrophobic solid surfaces. Does the protein change its structure upon adsorption on the surface? What are the molecular-level chemical features of the protein and surface that are responsible for these changes? An increased understanding of these questions is vital to ensure the continued development of biomaterials such as implants and biosensors. Our group tackles these questions using a combination of experimental and theoretical approaches.  In general, these questions require an investigation not only of the adsorbed molecule structure, but also of the surrounding solvent and surface characteristics of the solid surface.

adsorbed molecule structure

Hydrophobic surfaces are ubiquitous in medical implants, biosensors, and chromatographic supports.  The natural conformation of proteins is such that their hydrophobic residues are buried in their cores, suitable for aqueous environments in vivo.  When these molecules encounter hydrophobic surfaces such as polymers, they may alter their shape — often in an irreversible manner — in order to maximize surface contain of their hydrophobic residues.  This may have a significant impact on the function of the proteins.

Our group develops methods to probe the molecular-level interactions that occur between the biomolecules, the surface, and the interfacial solvent molecules.  Among these are experimental techniques such as nonlinear vibrational spectroscopy and ellipsometery.  We also employ electronic structure calculations and molecular dynamics simulations to complement and assist in the interpretation of the spectra.

interfacial water structure

When water molecules find themselves adjacent to a solid surface, they adopt a surprisingly well-ordered structure that extends over several molecular dimensions into the bulk water phase.  This is a consequence of reduced hydrogen-bonding opportunities next to a surface.  These ordered arrangements depend sensitively on the surface and solution conditions, and are ultimately responsible for the attraction and subsequent ordering of other molecules at the solid-liquid interface.  One may consider that the structure proteins adopt at solid surfaces is first in response to the local water environment near the surface.  Once biomolecules are able to penetrate the first few water molecules, only then are specific interactions with the surface realized.  Understanding interfacial solvent structure is therefore a key aspect of biomolecule-surface interactions.

We employ many of the same experimental and computational tools towards characterization water structure near a variety of solid surfaces.

substrate surface structure

The detailed structure of the solid surface, including the density and types of chemical functional groups present, is critical to an understanding of the adsorbed molecular structure.  In the case of complex surfaces such as polymers, the surface structure may be significantly different from that in the bulk polymer phase.

© DK Hore, Department of Chemistry, University of Victoria.