Hydrophobicity-modulating self-assembled morphologies of α-zein in aqueous ethanol

Protein fibrillation serves a broad range of biological functions from surface colonising to mechanically reinforcing structures; it is also associated with the development of neurodegenerative disorders. Although fibrillation is considered to be an inherent ability of polypeptides to form backbones, relevant studies have long concentrated on aqueous-soluble proteins rather than on insoluble structures. In this study, the self-assembly of hydrophobic proteins into amyloid nanofibrils was studied using -zein as a model protein. The self-assembled morphologies of -zein were determined by hydrophobic-hydrophilic characters of both the protein and the solvent. Upon thermally incubating in aqueous ethanol, -zein formed amyloid nanofibrils with lower ethanol compositions and near-neutral pHs, while acidic conditions and high ethanol compositions result in the formation of spherical aggregations. The fibrillation of -zein shows a great potential in serving as bio-based gels or reinforced fillers in food, cosmetic and pharmaceutical applications.