Self-assembly of amyloid beta peptide (A�) is a crucial step of fibrillogenesis, a hallmark mechanism of Alzheimer's disease. We discovered that a reversible assembly process of A�1-40 monomer can be controlled over 20 nm gold colloid's surface, under an alternation of external pH, at room temperature. The observed reversible self-assembly is a reproduction of an initial reversible step of fibrillogenesis. It is notable that the conformation under pH 4 corresponds to an oligomer form, which is regarded as an intermediate of fibrillogenesis. Furthermore, there was reversible color change as temperature decreased lower than 5 �C for A�1-40-coated 30 nm and 40 nm gold colloid. The unit constructs an oligomer over 20 nm gold colloid is a dimer, whereas a trimer is the main unit for an oligomer constructed over 30 or 40 nm gold colloids' surfaces. During the process of self-assembly, temperature was shifted up or down and an effect of an initial temperature was investigated. The A�1-40 monomers situated over 20 nm gold colloid tend to maintain the conformational feature constructed at an initial temperature even after the temperature was altered. This study exhibited two distinctly different self-assembly paths in an initial stage of fibrillogenesis.

Controlling reversible self-assembly path of amyloid � peptide over gold colloidal nanoparticles' surfaces

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.