Gold nanoparticle-based colorimetric sensor for studying the interactions of β-amyloid peptide with metallic ions

In this paper, a kind of beta-amyloid peptide (A beta 1-16) conjugated gold nanoparticles (A beta 1-16@GNPs) are prepared and employed as colorimetric indicator for studying the interaction of P-amyloid peptide with metallic ions (e.g. Zn2+ and Ca2+). In the presence of Zn2+, mono-dispersing A beta 1-16@GNPs enable to form aggregates or attach on the SHG-44 (human glioma cell) cellular surface which results in significant color change of the solution The experimental results indicate that Zn2+ can interact with A beta 1-16 and form Zn2+-3-amyloid peptide complexes In particular, in the presence of Zn2+, a time-dependent interaction of cells with A beta 1-16@GNP5 has been observed that may suggest different expression levels of p-amyloid peptide related proteins in various cell cycles In addition, the aggregating/binding process can be easily reversed by adding EDTA, a good chelated ligand of Zn2+, which gives further proof of the interaction mechanism. (C) 2009 Elsevier B.V All rights reserved.