Seminar March 2022 – Professor Heerklotz
On Thursday, March 17, 2022, a seminar on "Lipid-Detergent Interactions: Fundamentals and Applications" was held at 3.30 p.m. (CET).
The speaker was Professor Dr. Heiko Heerklotz from the Univeristy of Freiburg, Germany.
„Detergere“ stands for cleaning and hence, detergents in the strict sense are amphiphilic molecules that can solubilize poorly soluble molecules in micellar structures. We all know that instead of dirt in the laundry, micelles can also disperse and transport poorly soluble drugs or extract biomolecules out of membranes. Detergents are emulsifyers and wetting agents. Many permeation enhancers and preservatives act by compromising lipid barriers in a detergent-like fashion, just like their natural examples such as amphiphilic peptides or lysolipids. Finally, amphiphilic active pharmaceutical ingredients (APIs) may associate and enter, cross and/or affect membranes in ways resembling detergent action.
The primary aim of this online seminar is to provide a basic, structural and thermodynamic introduction into the phenomena underlying what we call „detergent-like action“. A key concept governing both micelle structures and many membrane effects is that of spontaneous curvature, the balance between the lateral interfacial area requirement in a given environment and the hydrophobic volume. In the simple cases, it correlates with the hydrophilic-lipophilic-balance (HLB) but it avoids the misinterpretations of the latter. It also distinguishes detergents as discussed here from surfactants forming other non-lamellar phases. Crucial properties are also the critical micelle concentration (CMC) and, closely related, the membrane-water partition coefficient as well as the rate of transmembrane flip-flop. These properties account not only for the details of the legendary „three stage model“ of membrane solubilization put forward by Helenius and Simons almost half a century ago. They provide quantitative explanations for many, sometimes maybe counterintuitive findings in the current lipid-detergent field.
If you need the slides of the presentation, please get in touch with us!