A Novel Magnetic Nanoparticle for Early Detection of Amyloid Plaques in Alzheimer's Disease.

Early diagnosis of Alzheimer's disease (AD) remains challenging even with the assistance of imaging. Radiation exposure limits the application of positron emission tomography (PET) for amyloid imaging. Magnetic resonance imaging (MRI) offers superior spatial resolution without the disadvantage of radiation exposure. We developed Mn0.6 Zn0.4 Fe2 O4 (MZF) modified by Pittsburgh compound B (PiB) to specifically bind to amyloid plaques. Coated with amphiphilic nanopolymer 6sPCL-b-P(MEO2 MA-co-OEGMA), PiB-MZF was stable, biocompatible, and approximately 100 nm in size. The R2 relaxation rate of PiB-MZF was 169.93 mM-1 S-1 demonstrating excellent superparamagnetism as a T2 negative contrast agent. PiB-MZF also showed no cytotoxicity in two cell lines. Immunohistochemistry indicated successful in vitro binding of PiB-MZF with Aβ plaque on 6 months old AD mice brain sections. In conclusion, PiB-MZF nanoparticles are preliminarily proven to have the potential for early detection of amyloid plaques and diagnosis of AD.