On the adsorption of magnetite nanoparticles on lysozyme amyloid fibrils

• MNP and amyloids have been characterized by TEM, SAXS and magneto-optical methods.
• The extent of adsorption is determined by the MNP concentration.
• The formed aggregates of MNP repeat the general rod-like structure of the fibrils.
• Aggregation is not observed when MNP are mixed with solution of lysozyme monomers.
• Amyloid fibrils affect magnetic properties of MNP + LAF mixtures.

An adsorption of magnetic nanoparticles (MNP) from electrostatically stabilized aqueous ferrofluids on amyloid fibrils of hen egg white lysozyme (HEWL) in 2 mg/mL acidic dispersions have been detected for the MNP concentration range of 0.01–0.1 vol.%. The association of the MNP with amyloid fibrils has been characterized by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) and magneto-optical measurements. It has been observed that the extent of adsorption is determined by the MNP concentration. When increasing the MNP concentration the formed aggregates of magnetic particles repeat the general rod-like structure of the fibrils. The effect is not observed when MNP are mixed with the solution of lysozyme monomers. The adsorption has been investigated with the aim to clarify previously found disaggregation activity of MNP in amyloid fibrils dispersions and to get deeper insight into interaction processes between amyloids and MNP. The observed effect is also discussed with respect to potential applications for ordering lysozyme amyloid fibrils in a liquid crystal phase under external magnetic fields.

Adsorption of magnetic nanoparticles on amyloid fibrils follows the bulk particle concentration in mixed dispersions and affects their magnetic properties.Figure optionsDownload as PowerPoint slide