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Heitz Group Research Projects

Dynamics of solvation in various media

Microheterogeneous Media...
A wide variety of polar molecules, such as proteins, enzymes, dyes, etc, can be hosted in the water pool of reverse micelles. Further, it is well known that a molecule's local microenvironment has a significant impact on it's physicochemical properties, which can change significantly depending on the amount of water present in the water pool. For example, the ability of an enzyme to retain functionality depends strongly on the surrounding environment. Entrapment may substantially alter the capability of the enzyme to function properly, if at all. Thus, solvation of these species within the water pool is highly dependent on the amount of water that is present.

Proteins...
The reversibility of protein binding to polymer surfaces is not well understood. Specifically, we are interested in the lysozyme sorption/desorption process. A distribution of protein binding is observed ranging from proteins that are irreversibly bound to a polymer to those that appear to bind reversibly with no mal effects upon desorption.

We are using a two-pronged approach to this system. Tryptophan (trp) residues serve as an intrinisic fluorescence source. However, since lysozyme contains six trp residues, each in its own microenvironment within the protein, deconvolving the contributions to the total signal from each trp is problematic. As an alternative approach we covalently attach an extrinsic fluorophore to the protein via the disulfide bridge chemistry. The labeling chemistry of acrylodan to free thiols has been documented.

Ionic Liquids...
Our group is interested in measuring the solvation dynamics in ILs and IL/solvent binary systems. Our recent work has focused on phosphonium ionic liquid-based mixed solvent systems. The cosolvent includes not only traditional organic solvents but supercritical fluids as well.

We are also interested in using ILs to studying protein denaturation and the impact of ILs on protein functionality.

Supercritical Fluids...
Another general interest of our group lies in the area of supercritical fluid technology. Supercritical fluids (particulary CO2) have gained much attention as a potential green solvents in recent years. We are focusing on determining the behavior of the unique solute/solvent interactions that occur near to the critical point.

Events

Fri, Dec 5

Major Exploration Day
9 am - 3:15 pm