Doctoral students seminar (January 29, 2019)

Location: 
Martin-Luther-Universität Halle-Wittenberg 
Von-Danckelmann-Platz 3, SR 1.06
06120 Halle (Saale) 

Time: 3.30pm - 5.00pm 

Link to OpenStreetMap

Low molecular weight aggregates of the amyloid-β-peptide (Aβ), so-called oligomers play a central role of the development of Alzheimer’s disease. One of the main techniques used to study them is fluorescence spectroscopy, for which peptides labeled with fluorescent tags are used. These tags are often covalently bound to the disordered N-terminus of the peptide assuming that hence they will not alter the aggregation process. However, we could find significant differences in the oligomer size distributions depending on the chosen dye. This talk will discuss the effect of four of the most commonly used fluorophores on the formation of oligomers of Aβ_1-40.

The origin of a number of neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, and prion diseases, is associated with the fibrillation of amyloid peptides. It has been widely described in the literature that fibril formation in vitro strongly depends on experimental conditions such as pH, temperature, concentration, or additives, such as nanoparticles, other peptides and proteins, lipids, surfactants, and polymers. In this contribution, we monitor amyloid-b 1-40 peptide (Aβ₄₀) fibril formation in a mixture with thermoresponsive poly(oligo(ethylene glycol)m acrylates), in which the polymer’s hydrophobicity is tuned by variation of the number of ethyleneglycol-units in the side-chain (m = 1-9). The polymers are prepared via RAFT-polymerization, obtaining a broad range of molecular weights (M_n = 1.5 to 35 kDa, polydispersity index PDI = 1.10 to 1.18) and tuneable cloud point temperatures (Tcp), ranging from 0 to 100 ^oC, respectively. The influence of the number of ethylene glycol units (m) within the polymer-backbone of (m = 1-9), allows to alter the hydrophilicity of these polymers, which is shown to modulate Aβ₄₀ aggregation.