Biomineralization of Fine Selenium Crystalline Rods and Amorphous Spheres

A simple aqueous phase method containing a water-soluble carrier protein, bovine serum albumin (BSA), has been presented for the synthesis of well-defined morphologies of nanobiomaterials. BSA has been used as a shape-directing agent to synthesize crystalline Se nanobars (NBs) and amorphous nanospheres in aqueous phase at a relatively low temperature of 85 °C. Na 2 SeO 3 is used as the Se source to achieve nanoselenium following hydrazine reduction. Well-defined multifacet NBs are produced when the amount of Na 2 SeO 3 is at least 6 times greater than that of BSA (on the basis of per residue), while amorphous spheres are formed with nearly a 1:1 ratio. Both morphologies have been fully characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopic (XPS) analysis. Results have shown that the shape-directing ability of unfolded BSA helped to achieve the formation of crystalline NBs, while its soft template effect directed the nanosphere formation.