Alzheimer's Amyloid-β (Aβ) peptide changes its conformation as it aggregates (1) and acquires toxicity, ultimately causing Alzheimer's disease. Since it is difficult to decouple conformational changes from aggregation, any cause-effect relationship between them remains poorly explored. Here we attach Alzheimer's Amyloid-β40 monomers to silver nanoparticles, preventing their aggregation, and study their conformation under aggregation-favoring conditions using SERS. Surprisingly, the α-helical character of the peptide remains unchanged between pH 10.5 and 5.5, while the solubility changes >100x. We infer that amyloid aggregation can start without significant conformational changes.A significant part of the aggregation / organization of this extra cellular peptide probably takes place in the in the lipid membrane. The affinity of the monomers and oligomers for the lipid membrane, and the conformation that they adopt there, remain open questions. We have recently found that Aβ exhibits a strong enhancement in its membrane-affinity as it transforms from monomers to oligomers (2). Using Fluorescence Correlation Spectroscopy, we have now established a rapid and quantitative assay for this affinity. Further, using SERS of lipid bilayer coated gold nano-particles, we are currently investigating the conformation of Aβ in lipid environments.1. Nag, S., Sarkar, B., Bandyopadhyay, A., Sahoo, B., Sreenivasan, V. K., Kombrabail, M., Muralidharan, C., and Maiti, S. (2011) Nature of the amyloid-beta monomer and the monomer-oligomer equilibrium. J Biol Chem 286, 13827-13833.2. Sarkar, B., Das, A. K., and Maiti, S. (2013) Thermodynamically stable amyloid-beta monomers have much lower membrane affinity than the small oligomers. Front Physiol 4, 84.