Porous, hollow, and ball-in-ball metal oxide microspheres: preparation, endocytosis, and cytotoxicity

The use of ultrasonic spray pyrolysis (USP) for the preparation of porous, hollow, and ball-in-ball nanomaterials and the cell toxicity of the nanomaterials was investigated. The role of the metal ions in the method is to induce a phase separation within the aerosol particles during the reactions that occur as the particles are rapidly heated. The surface area increases after the silica nanoparticles template was dissolved using wet chemical techniques and thus generating the pore structure. The toxicity studies with cells revealed that silica and titania nanocomposites have substantially lower cytotoxicity compared to metal and semiconductor nanomaterials. The acoustic cavitation in liquids irradiated with high-intensity ultrasound produces high-energy chemistry through intense local heating inside the gas phase of collapsing bubbles in the liquid. The results show that USP silica and titania microspheres are sufficiently non-cytotoxic to be used as drug-delivery systems.