Controlled fabrication of collagen-zinc phosphate hierarchical hybrid nanoflowers via a biomineralization process

Abstract

Due to their extraordinary features such as large surface areas, high porosity, and active surface functional groups, protein-inorganic nanoflowers have gained increasing attention. We have for the first time synthesized collagen-zinc phosphate hybrid nanoflowers via a mild biomineralization process. The incubation of 1.8 mM Zn(NO₃)₂ with 0.2 wt% of collagen protein in 20 mM PBS at 25 °C for 24 hours leads to the formation of exquisite flower-like nanomaterials with branched petals. Collagen may initiate the nucleation of the zinc phosphate crystals to form a framework of petals, and then glue the petals together. The synthesized collagen-Zn₃(PO₄)₂ nanoflowers display catalytic activity towards water oxidation. The triple helical structure and repetitive (Gly-X-Y)_n sequence pattern may endow collagen with a distinct capability to provide a superior biotemplate for producing hierarchical hybrid nanomaterials. The creation of collagen-zinc phosphate hybrid nanoflowers by our facile and green tactics significantly enhances our capability to construct hopeite-based functional materials.