Detection of Aβ Aggregation by Aggregation-Induced Emission (AIE) Probes in Alzheimer’s Disease

Alzheimer’s disease (AD) remains one of the most challenging neurodegenerative disorders, characterized by the extracellular accumulation of amyloid-β (Aβ) plaques and intracellular tau tangles. Among these, soluble Aβ oligomers are now recognized as the most neurotoxic species, disrupting synaptic function, calcium homeostasis, and neuronal survival. Conventional diagnostic methods, including antibody-based assays, electrochemical sensors, and classical fluorescent dyes such as Thioflavin T and Congo Red, suffer from limited sensitivity, poor selectivity, and incompatibility with early-stage or in vivo detection. Aggregation-induced emission (AIE) probes have emerged as transformative tools to overcome these barriers. AIE luminogens remain non-emissive in their monomeric state but exhibit strong fluorescence upon aggregation, offering high signal-to-noise ratios and minimal background interference. Recent advances include AIE nanoparticles and supramolecular assemblies capable of penetrating the blood–brain barrier, enabling real-time visualization of Aβ oligomers, fibrils, and plaques. Moreover, multifunctional AIE probes integrate detection with therapeutic functions, including inhibition of aggregation and photodynamic therapy. These developments highlight the potential of AIE-based systems for early diagnosis and theranostic applications in AD.