Self-Assembly of Amyloid Beta Peptide Over Dialkoxy Disulfide Functionalized Nano Gold Colloidal Particles

Aiming to more stably produce an oligomer form of amyloid beta (i.e., a key intermediate of fibrillogenesis which eventually leads to Alzheimer’s disease), the surface of gold colloids were functionalized with nitro-, phenyl-, chloro-, and methoxy-dibenzyloxy disulfide, and molecular interactions were investigated in a dimethyl sulfoxide environment. The transition of color change was observed at pHo as the pH value was lowered externally. As evidence of disulfide being adsorbed on the colloidal surface, the pHo values were dependent of each substituent of the dibenzyloxy disulfide compounds. The trend of pHo exhibited a parabolic relationship as a function of F-value (Swain-Lupton Field constant). Functionalization of gold colloidal surface with methoxy-dibenzyloxy disulfide achieved larger amplitude in repetitive peak shift between pH 4 and 10 implying a formation of an oligomer under the reversible process