Capturing Amyloid-β Oligomers by Stirring with Microscaled Iron Oxide Stir Bars into Magnetic Plaques to Reduce Cytotoxicity toward Neuronal Cells.

Soluble amyloid-β oligomers (oAβ)-induced neuronal death and inflammation response has been recognized as one of the major causes of Alzheimer's disease (AD). In this work, a novel strategy adopting silica-coated iron oxide stir bar (MSB)-based AD therapy system via magnetic stirring-induced capture of oAβ into magnetic plaques (mpAβ) and activation of microglia on cellular plaque clearance was developed. With oAβ being effectively converted into mpAβ, the neurotoxicity toward neuronal cells was thus greatly reduced. In addition to the good preservation of neurite outgrowth through the diminished uptake of oAβ, neurons treated with oAβ under magnetic stirring also exhibited comparable neuron-specific protein expression to those in the absence of oAβ. The phagocytic uptake of mpAβ by microglia was enhanced significantly as compared to the counterpart of oAβ, and the M1 polarization of microglia often occurring after the uptake of oAβ restricted to an appreciable extent. As a result, the inflammation induced by pro-inflammatory cytokines was greatly alleviated.