Imaging of Amyloidβ Aggregation Using a Novel Quantum dot Nanoprobe and its Advanced Applications

It has been proposed that amyloid β peptide (Aβ) aggregation in the brain plays a major role in the pathogenesis of Alzheimer's disease (AD). Real-time imaging technology for monitoring Aβ aggregation is a valuable approach for understanding the pathogenesis of AD. Quantum dots (QDs), which are fluorescent semiconductor nanocrystals, have evolved over the past decade as highly useful fluorescence probes for bio-nanoimaging due to their specific characteristics, such as nano-scale size, bright emission spectrum, long-term photostability, and multi-wavelength fluorescence emission by a single excitation. We have recently developed QD-labeled Aβ (QDAβ) nanoprobes which enable real-time imaging of Aβ aggregation, including oligomerization and fibrilization in vitro and in an intact cell system. In this chapter, we present the method for the preparation of QDAβ, as well as imaging and quantification of Aβ aggregation in vitro and in cultured cells. Furthermore, we also introduce a high-throughput microscopic drug-screening system for inhibiting Aβ aggregation.