Inhibition of Amyloid Aggregation and Toxicity with Janus Iron Oxide Nanoparticles

Amyloid aggregation is a ubiquitous form of protein misfolding underlying the pathologies of Alzheimer’s disease (AD), Parkinson’s disease (PD), and type 2 diabetes (T2D), three primary forms of human amyloid diseases. While much has been learned about the origin, diagnosis, and management of these neurological and metabolic disorders, no cure is currently available due in part to the dynamic and heterogeneous nature of the toxic oligomers induced by amyloid aggregation. Here, we synthesized β-casein-coated iron oxide nanoparticles (βCas IONPs) via a 2-(bis-((phosphonic acid)methyl)amino)ethyl-(poly(oligo ethylene glycol)methyl ether acrylate)-b-(poly(N-ethyl-2,3-dibromomaleimide)acrylate)-((butylthio)-carbonothioyl)thio propionate (BPA-P(OEGA-b-DBM)) block copolymer linker. Using a thioflavin T kinetic assay, transmission electron microscopy, Fourier transform infrared spectroscopy, discrete molecular dynamics simulations, and cell viability assays, we examined the Janus characteristics and the inhibition potential of βCas IONPs against the aggregation of amyloid β (Aβ), α synuclein (αS), and human islet amyloid polypeptide (IAPP), which are implicated in the pathologies of AD, PD, and T2D. Incubation of zebrafish embryos with the amyloid proteins largely inhibited hatching and elicited reactive oxygen species, which were effectively rescued by the inhibitor. Furthermore, Aβ-induced damage to the mouse brain was mitigated in vivo with the inhibitor. This study revealed the potential of Janus nanoparticles as a new nanomedicine against a diverse range of amyloid diseases.