A hemicyanine derivative for near-infrared imaging of β-amyloid plaques in Alzheimer's disease

The formation of amyloid- β (A β ) plaques in the brain is one of the main pathological features of Alzheimer's disease (AD). The imaging probes, capable of detecting A β deposition, are important tools for early diagnosis of AD. In this article, we designed, synthesized and evaluated a cyanine-based near-infrared fluorescence (NIRF) probe ZT-1 for the detection of A β deposits in the brain. The probe had excellent fluorescent properties with an emission maximum above 720 nm upon binding to A β aggregates with affinity of 445.0 nM ( K d ). Furthermore, ZT-1 exhibited good biostability, photostability, and binding selectivity toward A β 1-42 aggregates by in vitro fluorescence staining experiments. In vivo NIRF imaging result also revealed that our probe could efficiently differentiate transgenic and wild-type mice. All these studies indicated that ZT-1 is a promising fluorescent probe for A β plaques in the AD brains.