Ag Nanometallic Surfaces for Self-Assembled Ordered Morphologies of Zein.

Nanometallic surfaces of Ag nanoparticles (NPs) catalyzed the self-aggregation behavior of zein in different ordered morphologies such as cubes, rectangles, and bars. This was studied in a ternary in situ reaction (AgNO + zein + water), where zein performed the reduction as well as stabilization of Ag NPs. This reaction produced small Ag NPs of less than 10 nm predominantly bound with {111} crystal planes, which attracted the surface adsorption of zein. Surface-adsorbed zein initiated the protein seeding and converted the tertiary structure of protein into open β-pleated structure with aqueous exposed hydrophobic domains. A layered deposition of β-pleats on different crystal planes of Ag NPs derived them to nearly monodispersed cubic morphologies. The mechanistic aspects of self-aggregation of zein in the presence of nanometallic surfaces hold possible scenarios for simple and straightforward routes of protein crystallization.