The reversible self-assembly process of amyloid beta peptide (A�) or albumin coated gold colloid is known to be sensitive to pH in an aqueous environment. However, no detail study of aggregation process under different solvent environment has been conducted up to now. Using Transmission Electron Microscopy, we directly observed the self-assembly process of the A� or albumin coated gold nanocolloids diluted in dimethyl sulfoxide (DMSO). We found that self-assembly process in DMSO was irreversible after a change in pH from 10 to 4 for both albumin and A� coated gold colloids. We interpreted that water environment prepared a weak interaction between protein and gold colloidal surface and enabled the proteins to undergo a reversible process. On the other hand, DMSO must interact relatively strongly with proteins and restricted a structural transformation required in the self-assembly process. It clarified that the solvent environment significantly contributed to a reversibility of the aggregation process.

Solvent dependent aggregation of gold nanocolloids

246th National Meeting (2013)

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