Facile and green fabrication of multiple magnetite nano-cores@void@porous shell microspheres for delivery vehicles

Abstract

Multiple magnetite nano-cores@void@porous shell microspheres have been fabricated by using the algal cell wall as the hollow porous shell precursor and the intracellular substances as the reducing agents to form magnetite cores inside the microspheres via hydrothermal reactions. This method not only simplifies the fabricating steps and supersedes harmful chemical reagents, but also endows the microspheres with a uniform size (∼2.5 μm), porous shell (∼15 nm), multiple magnetite nano-cores (∼25 nm) and high void volume ratio (>70%). The product presents fast magnetic separation and redispersibility as well as pH-switched protein auto-loading (high capacity >600 mg g⁻¹) and unloading as high performance delivery vehicles.