Joan E Curry

Joan E Curry

Associate Department Head, Environmental Science
Professor, Environmental Science
Member of the Graduate Faculty
Professor, BIO5 Institute
Primary Department
Contact
(520) 626-5081

Research Interest

Research Interest

Joan Curry, PhD, stands in the field of research related to interfacial chemistry, which is a focus within physical chemistry. Within interfacial chemistry, she focuses on chemistry of molecules at the interfaces where solids and liquids come together. The term solid here includes mineral and bacterial surfaces found in soils and sediments, metal and oxide machine surfaces and cell surfaces found in the human body. Molecules can be water and ions that bathe soil surfaces, organics that lubricate machine parts and large biomacromolecules, such as proteins and lipopolysaccharides, attached to cells that mediate cell adhesion. Her specific interests are: 1) determining the effect of confinement on liquids in general and lubricants in particular and 2) characterizing the adhesive properties of cell surface biomacromolecules. The primary goal of this work is to understand how biomacromolecules that cover cell surfaces influence the interaction and adhesion of cells with other cells and with solid surfaces. Cells can be either bacteria or human cells. It is important to understand bacterial adhesion because it is the first step in biofilm formation, which has numerous undesirable consequences ranging from heat exchanger fouling to medical implant infections. Currently, very little is known about how bacterial surface biomacromolecules mediate adhesion and therefore it is still not possible to control or manipulate the process. Human cell adhesion is also mediated by biomacromolecules, in particular proteins that bind to one another through specific lock and key mechanisms. The structure of many cell adhesion proteins is well known but their function is still poorly understood. In collaboration with Ronald Heimark (Surgery), Dr. Curry is working to understand how heavy metals such as cadmium affect the binding of cell adhesion proteins called cadherins. This work will help scientists understand better how heavy metals may lead to birth defects and in adults could accelerate cardiovascular disease. This work is experimental and involves direct force measurements between biomembrane covered mica surfaces with the Surface Forces Apparatus (SFA). With the SFA it is possible to measure the magnitude and distance dependence of molecular forces acting between two flat surfaces with angstrom and nanonewton resolution.

Publications

Curry, J. E., & McQuarrie, D. A. (1992). On dielectric saturation modeling in a continuum solvent. Journal of Colloid And Interface Science, 154(1), 289-294.

Abstract:

The linear Poisson-Boltzmann equation is solved with a variable dielectric constant to account for dielectric saturation. Two different spatially dependent forms of the dielectric constant are compared. It is shown that the electrostatic repulsion between two flat plates is decreased by dielectric saturation and that it depends in a complicated way on both the dielectric constant and the electric field. © 1992.

Curry, J., Kim, S., Cho, K., & Curry, J. E. (2005). Measurements of the thickness compressibility of an n-octadecyltriethoxysilane monolayer self-assembled on mica. Langmuir : the ACS journal of surfaces and colloids, 21(18).

The surface forces apparatus technique and the Johnson-Kendall-Roberts theory were used to study the elastic properties of an n-octadecyltriethoxysilane self-assembled monolayer (OTE-SAM) on both untreated and plasma-treated mica. Our aim was to measure the thickness compressibilities of OTE monolayers on untreated and plasma-treated mica and to estimate their surface densities and phase-states from the film compressibility. The compressibility moduli of OTE are (0.96 +/- 0.02) x 10(8) N/m(2) on untreated mica and (1.24 +/- 0.06) x 10(8) N/m(2) on plasma-treated mica. This work suggests that the OTE phase-state is pseudocrystalline. In addition, the results from the compressibility measurements in water vapor suggest that the OTE-SAM on both untreated and plasma-treated mica is not homogeneous but rather contains both crystalline polymerized OTE domains and somewhat hydrophilic gaseous regions.

Curry, J. E., Feller, S. E., & McQuarrie, D. A. (1991). A variational solution of the nonlinear poisson-boltzmann equation inside a spherical cavity. Journal of Colloid And Interface Science, 143(2), 527-531.

Abstract:

The nonlinear Poisson-Boltzmann equation is solved variationally to obtain the electrostatic potential profile in a spherical cavity containing an aqueous electrolyte solution. The variational solution is based on the linear solution to the Poisson-Boltzmann equation. It is found that a three-parameter trial function provides sufficient accuracy to make the variational potential profile indistinguishable from exact numerical results. The variational solution is valid over the concentration, size, and surface potential ranges typical of phospholipid vesicles. It is anticipated that this solution will be useful in determining the stability of membraneous vesicles and reverse micelles. © 1991.

Curry, J., Baughman, K. F., Maier, R. M., Norris, T. A., Beam, B. M., Mudalige, A., Pemberton, J. E., & Curry, J. E. (2010). Evaporative deposition patterns of bacteria from a sessile drop: effect of changes in surface wettability due to exposure to a laboratory atmosphere. Langmuir : the ACS journal of surfaces and colloids, 26(10).
BIO5 Collaborators
Joan E Curry, Raina Margaret Maier

Evaporative deposition from a sessile drop is a simple and appealing way to deposit materials on a surface. In this work, we deposit living, motile colloidal particles (bacteria) on mica from drops of aqueous solution. We show for the first time that it is possible to produce a continuous variation in the deposition pattern from ring deposits to cellular pattern deposits by incremental changes in surface wettability which we achieve by timed exposure of the mica surface to the atmosphere. We show that it is possible to change the contact angle of the drop from less than 5 degrees to near 20 degrees by choice of atmospheric exposure time. This controls the extent of drop spreading, which in turn determines the architecture of the deposition pattern.

Stroud, W. J., Curry, J. E., & Cushman, J. H. (2001). Capillary condensation and snap-off in nanoscale contacts. Langmuir, 17(3), 688-698.

Abstract:

When a surface is placed in a vapor, several layers of molecules may adsorb depending on the intermolecular forces involved. As two such surfaces are brought together, a critical point is reached at which the gas condenses between the surfaces, forming a capillary across the gap. A cohesive force is associated with the condensed bridge. The reverse process wherein the capillary bridge degenerates as the surfaces are moved apart is called snap-off. These processes play a profound role on scales from the nano to the macro. We have studied this phenomenon via isostrain grand canonical Monte Carlo statistical mechanical simulations for Lennard-Jones fluids. Specifically, we have examined capillary condensation and snap-off between nanocontacts, infinite rectilinear nanowires, and finite rectilinear nanoplatelets, where macroscale concepts and theories are just about impossible to apply. These results are compared to condensation between infinite parallel plates. We discuss our results in terms of the Kelvin equation and van der Waals film-thickening model.