Real-time Amyloid Aggregation Monitoring with a Photonic Crystal-based Approach

We propose the application of a new label-free optical technique based on photonic nanostructures to real-time monitor the amyloid-beta 1-42 (A?(1-42)) fibrillization, including the early stages of the aggregation process, which are related to the onset of the Alzheimer's Disease (AD). The aggregation of A? peptides into amyloid fibrils has commonly been assocd. with neuronal death, which culminates in the clin. features of the incurable degenerative AD. Recent studies revealed that cell toxicity is detd. by the formation of sol. oligomeric forms of A? peptides in the early stages of aggregation. At this phase, classical amyloid detection techniques lack in sensitivity. Upon a chem. passivation of the sensing surface by means of polyethylene glycol, the proposed approach allows an accurate, real-time monitoring of the refractive index variation of the soln., wherein A?(1-42) peptides are aggregating. This measurement is directly related to the aggregation state of the peptide throughout oligomerization and subsequent fibrillization. Our findings open new perspectives in the understanding of the dynamics of amyloid formation, and validate this approach as a new and powerful method to screen aggregation at early stages. [on SciFinder(R)]