Study of Amyloidogenic Peptide Aggregation via Dielectric Relalxation Spectroscopy

Recent studies suggest that Alzheimer's disease (AD) and Type II Diabetic Disease are interlinked. The Aβ amyloid, associated with the AD, and insulin modulate each other's functions in the brain. However, the underlying mechanism of Aβ-insulin interaction is not well understood.
Here, we present our results on the Aβ1-42 and Aβ42-1 scrambled and their interactions with a bovine serum albumin - glycerol solution and insulin to mimic in vivo conditions. We used dielectric relaxation spectroscopy to measure the dielectric permittivity as a function of frequency (10-3 Hz to 10-7 Hz), temperature (133K to 223K), and aggregation time (0h-24h). Multiple Havriliak-Negami dispersions plus an additional conductivity and electrode polarization term were used to fit the relaxation processes. We observed that the dielectric response of Aβ1-42 and Aβ42-1 scrambled can be detected and differentiated via the evolution of the relaxation peak over time.