Study of-amyloid adsorption and aggregation on graphite by STM and AFM

Alzheimers disease is the major cause of dementia and the fourth leading cause of death in the developed world after heart disease, cancer and stroke. Pathologi-cally, one of major hallmarks of Alzheimers disease is the formation of insoluble deposits of -amyloid (A) both as diffuse and senile plaques in the brain tissue. The plaques are fibrous masses composed primarily of the 40-42 resi-due A peptides. The two most abundant forms of A are, respectively, the 40 and 42 residue peptide -amylo…

Study of-amyloid adsorption and aggregation on graphite by STM and AFM

The scanning tunneling microscopy (STM) and the atomic force microscopy (AFM) have been applied to the direct study of the adsorption and aggregation of -amyloid(1-42)(A42) on the hydrophobic graphite surface. It was found that A42 were preferentially adsorbed on graphite defects such as the edges. A42 peptides self-assembled into intermediate protofibrils, which in turn self-associated to form fibrils. Usually, two or more fibrils intertwined to form the helical structure. These results will provide an important clue to studying the aggregation proc-ess of -amyloid.