Nanoparticles modulate membrane interactions of human Islet amyloid polypeptide (hIAPP)

The dramatic expansion of nanotechnology applications, particularly the advent of nanomaterials and nanoparticles (NPs) into the consumer economy, have led to heightened awareness of their potential health risks. This study examines the impact of several NPs upon membrane-induced aggregation and bilayer interactions of the human Islet amyloid polypeptide (hIAPP). We report that several NPs - polymeric NPs, TiO2 NPs, and Au NPs displaying coating layers exhibiting different electrostatic charges - did not significantly interfere with the fibrillation process and fibril morphology of hIAPP, both in buffer or in biomimetic DMPC:DMPG vesicle solutions. Spectroscopic and microscopic analyses suggest, in fact, that the NPs promoted membrane-induced fibrillation. Importantly, we find that all the NPs examined, regardless of composition or surface properties, gave rise to more pronounced, synergistic bilayer interactions when co-incubated with hIAPP. NP-enhanced bilayer interactions of hIAPP might point to possible toxicity and pathogenicity risks of amyloidogenic peptides in the presence of NPs.