Scanning ion-conductance microscopy for studying β-amyloid aggregate formation on living cell surface

Abstract

Alzheimers disease (AD) is the most common form of dementia, a progressive neurological disorder characterized by short and long-term memory loss, including cognitive and functional impairment, which is refractory to current therapy. It is suggested that the aggregation of {beta}-amyloid (A{beta}) peptide on neuronal cell surface leads to various deviations of its vital function due to myriad pathways defined by internalization of calcium ions, apoptosis promotion, reduction of membrane potential, synaptic activity loss etc. These are associated with structural reorganizations and pathologies of the cell cytoskeleton mainly involving actin filaments and microtubules, and consequently - alterations of cell mechanical properties. Thus, the effect of amyloid oligomers on cells Youngs modulus has been observed in a variety of studies. However, the precise connection between the formation of amyloid aggregates on cell membranes and their effects on local mechanical properties of living cells is still unresolved. In this work, we have used correlative scanning ion-conductance microscopy (SICM) to study cell topography, Youngs modulus mapping and confocal imaging of A{beta} aggregates formation on living cell surfaces with subsequent assessment of the reactive oxygen species levels inside single cells using platinum nanoelectrodes. We showed that correlative SICM technique, in conjunction with topography mapping and confocal imaging, can be used for Patch-Clamp recordings from living cells with evidently formed FAM-labeled A{beta} aggregates on its surface. As we demonstrated, SICM can be successfully applied to studying cytotoxicity mechanisms of A{beta} aggregates on living cell surface.