Post-Doctoral Position: Department of Chemical Engineering and Materials
Science, University of Minnesota
beginning immediately
Relating Monolayer Dynamics and Adsorption to Composition and Morphology An essential, function of LS is to prevent the Laplace instability, which drives gas out of smaller alveoli and into larger ones, effectively deflating smaller alveoli and thickening the alveolar lining fluid. The Laplace Instability occurs when the capillary pressure, ΔP=2γ/R, in small alveoli (radius RS) exceeds that of larger alveoli (radius RL): 2γ/RS > 2γ/RL. This post-doctoral position is designed to examine the hypothesis that the dynamic resistance of the LS monolayer to compression can reverse the Laplace instability. The dilatational modulus, 𝜀 𝜔 = 𝐴 𝜔 𝜕𝛾 𝜕𝐴 , relates the change in surface tension, γ, to the change in molecular area, A. For 𝜕 𝛾 𝑅 𝜕𝑅 = 2𝜀 – 𝛾 𝑅! > 0, or 2ε−γ >0, the Laplace pressure decreases with decreasing radius, suppressing the Laplace Instability. However, if 2ε−γ is negative, even small variations in inflation would drive spontaneous collapse of some alveoli, and hyper-extension of others. My group
has designed and built a novel capillary pressure microtensiometer to measure ε. The post-doc will map out ε for clinical and model lung surfactants as a function of surface pressure and frequency to determine the effects of solid phase fraction (related to saturated vs. unsaturated lipid fraction), domain morphology (related to lung surfactant proteins SP-B and SP-C, cholesterol and fatty acid fractions) and subphase compositions of lysolipids and/or albumin. If the Laplace instability does play a causative role in the progression of ARDS, then any successful therapy must reverse this instability. Reversing the Laplace instability requires understanding how to accelerate the interfacial adsorption of LS relative to albumin and lyso-PC, which we propose to
study using confocal microscopy.
The ideal applicant would be a trained experimentalist with a background in the physics and chemistry of interfacial phenomena. Prior experience with confocal or two-photon microscopy, design of experimental apparatus, Labview experience, handling and preparing lipid and protein mixtures, atomic force microscopy, Langmuir isotherms.
Previous students and post-docs on this project have gone on to careers in both industry and academia.
Salary: $42-45K depending on experience + benefits. Minimum duration one year, with extension depending on progress. Applications should be send to Joseph Zasadzinski (biosketch/CV + career plans + names of two referees or two recommendation letters). Position open until filled.
