Mechanical manipulation of Alzheimer’s amyloid β1–42 fibrils

Nanomechanics of Amyloid Materials Studied by Atomic Force Microscopy

“…All of the force curves exhibited non-linear elastic mechanical response followed by one or several rupture events. The absence of force plateau, which is a characteristic pattern of the unzipping of -sheets from the fibril, implies that the high packing density in mature glucagon amyloid fibrils allows a stable confinement of the peptide molecules in the twisted fibrillar structure, in contrast to A amyloid fibrils (Karsai et al, 2006;Kellermayer, et al, 2005). The stable structure is further confirmed by repeatedly stretching a single fibril for 1000 times.…”

Biophysical characterization of alpha-synuclein aggregates : Parkinson's disease at the nanoscale

“…Karsai et al (2006) performed force spectroscopy on Aβ 1−42 fibrils and found that some fibrils show plateaus of constant force while being extended, indicating the steady 'unzipping' of a filament from a fibril, while others display reversible non-linear elastic stretching without any hysteresis ( fig. 2.8).…”

“…Both of these phenomena are completely reversible: even the segment that is unzipped in fig. 2.8a re-attaches and can be unzipped again many times (Karsai et al, 2006). The unzipping force attributed to one Aβ 1−42 filament is 23 pN, and the distance between two Aβ molecules is 4.7Å (Serpell, 2000) so that the associated bond free energy is ∆G = F ∆x = 23 pN · 0.47 nm = 1 · 10 −20 J, corresponding to ∼ 6 kJ/mol, which is similar to the free energy of one hydrogen bond of ∼ 4 − 8 kJ/mol (see table 5.1 on page 84).…”

Nano-biomechanical investigation of living endothelial cells

“…It is suitable for applications at large scale range, from living cells (Bálint et al 2007a) through membranes (Végh et al 2011) down to single molecules (Bálint et al 2007b;Gad et al 1997;Karsai et al 2006), covering over four orders of magnitude.…”