Designing BODIPY-based probes for fluorescence imaging of β-amyloid plaques

Alzheimer's disease (AD) is an important neurological disorder that affects mostly the elderly by diminishing the quality of life to a drastic extent. It is under study worldwide as it is considered to be one of the most important diseases. Nevertheless, an effective treatment remains elusive. Today, more than 24 million people have been affected by AD worldwide and it is estimated that number will reach 100 million people by 2050. Considering the lack of a cure, early detection and monitoring are therefore very signicant for satisfactorily managing this disease. Accurate diagnosis rests on the detection of b-Amyloid (Ab) plaques since the progression of disease is linked to the appearance and accumulation of these plaques. Ab plaques are formed by the amyloid precursor proteins (APP) which are mainly composed of Ab40 and Ab42(43) peptides that are deposited early, andmost likely, selectively in the senile plaques following cleavage with b-(BACE) and g-secretases. These plaques may play a role in other neurodegenerative diseases such as Creutzfeldt–Jakob and carpal tunnel syndrome, it is also possible to observe Ab plaques formation in the brains of the patients with those diseases. Ab40 and Ab42 are known to be the main amyloid peptides in humans. Although Ab40 is more abundant one, Ab42 forms aggregates more rapidly. It is thought that, free radicals result in oxidative stress, which play important role in protein metabolism, may be the major reason for the Ab aggregation. Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used conventional techniques