Biophysical Characteristics of Human Neuroblastoma Cell in Oligomeric $\beta $ -Amyloid (1–40) Cytotoxicity

Beta amyloid (Aβ) peptide, which is a common neuropathological hallmark deposit in the brain of patients with Alzheimer's disease, typically comprises 39-43 amino acid residues. Aβ peptides exist as isoforms of Aβ
_1-40
and Aβ
_1-42
with various lengths. In this research, atomic force microscopy (AFM) was applied to investigate Aβ
_1-40
aggregations in Hank's Balanced Salt Solution. Toxic effect of Aβ
_1-40
oligomer was investigated in live SH-SY5Y neuroblastoma cells by characterizing cell morphology and cell mechanics using high-resolution AFM scanning. Aβ
_1-40
oligomer-induced cytoskeleton reorganization was also observed under confocal microscopy, and it can account for reduction in Young's modulus of cells. Meanwhile, phosphorylation of tau increased after Aβ
_1-40
oligomer treatment, possibly resulting in microtubule disassembly. This paper demonstrates the linkage between cellular mechanical changes and neurodegeneration mediated by Aβ
_1-40
. The method used implies promising applications of real-time monitoring of cellular mechanical properties given the toxic effects of Aβ
_1-40
on living neuronal cells.