Aβ-Targeting Bifunctional Chelators (BFCs) for Potential Therapeutic and PET Imaging Applications

Currently, more than 55 million people live with dementia worldwide, and there are nearly 10 million new cases every year. Alzheimer's disease (AD) is the most common neurodegenerative disease resulting in personality changes, cognitive impairment, memory loss, and physical disability. Diagnosis of AD is often missed or delayed in clinical practice due to the fact that cognitive deterioration occurs already in the later stages of the disease. Thus, methods to improve early detection would provide opportunities for early treatment of disease. All FDA-approved PET imaging agents for Aβ plaques use short-lived radioisotopes such as ¹¹C (t_1/2 = 20.4 min) and ¹⁸F (t_1/2 = 109.8 min), which limit their widespread use. Thus, a novel metal-based imaging agent for visualization of Aβ plaques is of interest, due to the simplicity of its synthesis and the longer lifetimes of its constituent isotopes. We have previously summarized a metal-containing drug for positron emission tomography (PET), magnetic resonance imaging (MRI), and single-photon emission computed tomography (SPECT) imaging of Alzheimer's disease. In this review, we have summarized a recent advance in design of Aβ-targeting bifunctional chelators for potential therapeutic and PET imaging applications, reported after our previous review.