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Updated: Jul 22, 2026

Flash Freezing and Cryosectioning E12.5 Mouse Brain
Published on: May 28, 2007
Observing a molecular knife at work
Xiaoyun Chen1, Haizhong Tang, Mark A Even
1Department of Chemistry, University of Michigan, Ann Arbor, 48109, USA.
Abstract:
Sum frequency generation (SFG) vibrational spectroscopy has been employed to study the molecular interactions between a single substrate supported lipid bilayer and an amphiphilic antibiotic compound 1, with a design based on the common structural motif of natural antimicrobial peptides. The interfacial sensitivity of SFG allows real-time in situ monitoring of ordering changes in both leaflets of the bilayer and orientation of 1 simultaneously. A critical concentration of about 0.8 microg/mL of 1 is found, above which the inner leaflet of the bilayer is significantly perturbed. This concentration corresponds well to the minimum inhibition concentration of 1 that is obtained from bacterial experiments. Orientation of 1 in the bilayer is shown to be perpendicular to the bilayer surface, in agreement with simulation results. SFG can be developed into a very informative technique for studying the cell membrane and the interactions of membrane-active molecules.
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