Field amplified sample stacking of amyloid beta (1-42) oligomers using capillary electrophoresis

Abstract

Oligomeric forms of the amyloid beta (Aβ) protein have been indicated to be an important factor in the development of Alzheimer's disease (AD). Since the oligomeric forms of Aβ can vary in size and conformation, it is vital to understand the early stages of Aβ aggregation in order to improve the care and treatment of patients with AD. This is the first study to determine the effect of field amplified sample stacking (FASS) on the separation of oligomeric forms of Aβ1-42 using capillary electrophoresis (CE) with ultraviolet (UV) detection. UV-CE was able to separate two different species of Aβ1-42 oligomers (<7 mers and 7–22 mers). Although FASS required the use of a higher ionic strength buffer, Aβ1-42 oligomers had the same aggregation behavior as under the non-FASS conditions with only small changes in the amounts of oligomers observed. In general, FASS provided smaller peak widths (>75% average reduction) and increased peak heights (>60% average increase) when compared to non-FASS conditions. UV-CE with FASS also provided higher resolution between the Aβ1-42 oligomers for all aggregation time points studied. In addition, Congo red and Orange G inhibition studies were used to help evaluate the conformation of the observed species. This work demonstrates the ability of UV-CE employing FASS to provide higher resolution between oligomeric forms of Aβ1-42 without significantly altering their aggregation.

Recent developments in capillary and microchip electroseparations of peptides (2015–mid 2017)

“…Special reviews and papers deal with the particular sample clean‐up techniques, such as SPE , solid‐phase microextraction (SPME) , electromembrane extraction , selective electromembrane extraction based on isoelectric point , magneto‐immuno capture , and on‐line electrodriven sample‐stacking techniques . The latter electrodriven procedures include field amplified sample stacking , field enhanced or field‐amplified sample injection (FESI or FASI) ; large volume sample stacking (LVSS) , transient‐ITP (t‐ITP) , multiple capillary ITP (CITP) with repetitive hydrodynamic injection , dynamic pH junction , electrokinetic supercharging , and sweeping . The classical off‐line formats of SPE are nowadays being substituted by their on‐line modes.…”

Isolation and Self-Association Studies of Beta-Lactoglobulin

“…Capillary electrophoresis (CE) is one of such techniques and provides a rapid and efficient protein analysis with a low sample and buffer consumption [ 35 , 36 ]. The technique is typically applied for protein separation [ 37 , 38 , 39 ], but recently the use of CE as a screening method for the protein oligomers determinations is attracting attention [ 40 , 41 ]. Therefore, the potential use of CE for rapidly monitoring of β-LG forms at different pH conditions was studied in this paper.…”

A Simple Separation Method of the Protein and Polystyrene Bead-Labeled Protein for Enhancing the Performance of Fluorescent Sensor

“…Dielectrophoresis (DEP), resulting from inhomogeneous electric fields, has been utilized for the specific manipulation of the particles, cells, and viruses as well as biomolecules such as DNA and even single protein, because of its simplicity, efficiency, and usability [ 16 – 18 ]. The intensity of the DEP force is dominated by the size of the molecules and the strength of the electric fields, which occurred between the electrodes, so that various molecules are affected by a different intensity of the force according to the size of the molecules and the structure of the electrode.…”