Label-Free Detection and Self-Aggregation of Amyloid ?-Peptides Based on Plasmonic Effects Induced by Ag Nanoparticles: Implications in Alzheimer’s Disease Diagnosis

Plasmon-assisted effects were used in this work to study the dynamical behavior of amyloid ? peptides (A?), particular A?(25–35), on silver nanoparticles. Amyloid derive from proteolytic cleavage glycoprotein named precursor protein (APP). A?(25–35) represents sequence that concentrates biological active region all peptide family, being shortest fragment A? retains toxicity full length. The plasmon employed localized surface resonance (LSPR), hybridization resulting plasmonic NPs aggregation, and enhancement electric field leading so-called surface-enhanced Raman scattering (SERS) spectroscopy nanostructures. While LSPR nanoparticles are highly sensitive adsorption processes undergone by these metal surface, direct nonlabeled SERS spectra provided valuable information regarding secondary structure peptides. Specifically, revealed interaction mechanism with structural rearrangement involved self-aggregation fibrillation. These also followed at different concentrations. Plasmon results obtained transmission electron microscopy (TEM) images corroborated formation supramolecular aggregates Nanospheres protofibrils formed first stages assembly identified TEM. physicochemical will be great importance design plasmon-based nanoplatforms for simultaneous detection characterization. Furthermore, platforms have promising applications Alzheimer’s disease its treatment based bioaccumulation toxic NPs, where they can trapped removed systems, thus reducing their neurotoxicity.