Designing nanostructured microspheres with well-defined outlines by mixing carboxyl-functionalized amylose and magnetite via ultrasound

Magnetite-nanostructured amylose (AMY) microspheres with well-defined outlines were developed through an ultrasound-induced hydroalcoholic emulsion in 30 s. The formation of sphere-shaped polysaccharide particles occurred, upon ultrasound, via a complexation of iron ions from magnetite with carboxyl groups from carboxylated AMY at the interior of the benzyl alcohol-confined water droplets, within which the polysaccharide chains would have been fine-tuned. The introduction of magnetite into the microspheres under ultrasonic irradiation produced sub-1.78 μm size spheres and also rendered a narrower sphere size distribution. Spherical crystalline structures of magnetite with diameters ranging from 28 nm to 140 nm were observed in the AMY microspheres, indicating an excellent dispersion of the iron oxides if compared to its initial diameter (<5 μm). We supposed that both the strong interactions resultant from complexation of iron ions with carboxyl groups and the ultrasound waves have effectively contributed to disaggregate magnetic particles, dispersing them into smaller crystals. This work offers a self-healing, readily synthesized, friendly environmentally device that can be used in important fields of the health science and material technology.

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► Magnetite-nanostructured amylose microspheres were developed in 30 s.
► The spheres were formed at the interior of the oil-confined water droplets.
► The introduction of magnetite produced sub-1.78 μm size spheres.
► The amylose–Fe interactions effectively contributed to disaggregate magnetite.