Capturing the interaction potential of amyloidogenic proteins

Experimentally derived static structure factors obtained for the aggregation-prone protein insulin were analyzed with a statistical mechanical model based on the Derjaguin-Landau-Verwey-Overbeek potential. The data reveal that the protein self-assembles into equilibrium clusters already at low concentrations. Furthermore, striking differences regarding interaction forces between aggregation-prone proteins such as insulin in the preaggregated regime and natively stable globular proteins are found.     

Synthesis and Host-abilities of some New Corands Bearing Uncommon Chiral Spacer Units

Benzo- and naphtho-ethylene glycols are prepared from dihydroxy-benzenes or -naphthalenes and the corresponding chloroethoxyethanols using known procedures. Cyclocondensation reactions of these open-chain diols with the chiral and concave tetra-t-butyl-2,6,9-trioxabicyclo[3.3.1]nonadiene (“bridged bisdioxine”) bisacid chloride afford several new corands. In one case, besides the expected macrocycle, an open-chain podand is obtained and further cyclized to a large 2:2 macrocycle. The bridged bisdioxine spacer may also be converted into the tetraoxaadamantane scaffold as shown with an example. Extraction experiments employing selected corands towards various metal ions show a significant host-property towards Hg(II) salts for those macrocycles having o-disubstituted aryl groups incorporated, thus forming 1:1 complexes. NMR titration studies with sodium thiocyanate as well as with some organic guests do not exhibit significant host–guest interactions, in the case of Hg(II) thiocyanate a weak complexation was determined.     

Modeling and simulation of pH-sensitive hydrogels

Polyelectrolyte gels are ductile elastic electroactive materials. They consist of a polymer network with bound charged groups and a liquid phase with mobile ions. In water-based solutions, these gels show enormous swelling capabilities under the influence of different types of stimulation, such as chemical, electrical, or thermal. In the present work, a coupled multi-field formulation for polyelectrolyte gels using the finite element method is applied. Additionally to the three given fields??mechanical, electrical, and chemical fields??the dissociation reactions of the bound charges in the gel phase are considered. In this study, chemical stimulation (change of pH or salt concentration) is investigated for gels placed in solution baths. By changing the ambient conditions, we are able to simulate both pH stimulation and change of salt concentration, and to give the change of the mobile and bound ion concentrations, the electric potential, and the mechanical displacement.