Effect of Fe3O4 magnetic nanoparticles on lysozyme amyloid aggregation

Peptide amyloid aggregation is a hallmark of several human pathologies termed amyloid diseases. We have investigated the effect of electrostatically stabilized magnetic nanoparticles of Fe3O4 on the amyloid aggregation of lysozyme, as a prototypical amyloidogenic protein. Thioflavin T fluorescence assay and atomic force microscopy were used for monitoring the inhibiting and disassembly activity of magnetic nanoparticles of Fe3O4. We have found that magnetic Fe3O4 nanoparticles are able to interact with lysozyme amyloids in vitro leading to a reduction of the amyloid aggregates, thus promoting depolymerization; the studied nanoparticles also inhibit lysozyme amyloid aggregation. The ability to inhibit lysozyme amyloid formation and promote lysozyme amyloid disassembly exhibit concentration-dependent characteristics with IC50 = 0.65 mg ml(-1) and DC50 = 0.16 mg ml(-1) indicating that nanoparticles interfere with lysozyme aggregation already at stoichiometric concentrations. These features make Fe3O4 nanoparticles of potential interest as therapeutic agents against amyloid diseases and their non-risk exploitation in nanomedicine and nanodiagnostics.