 Magnetite nanoparticles, FE-304, are highly promising materials for medical applications due to their ability to carry drugs or enzymes. To reduce the saturation magnetization of these particles, they can be incorporated into mesoporous materials. Direct synthesis of mesoporous structures has also been investigated, with success achieved through coprecipitation reactions at room temperature. These reactions use various bases, including sodium hydroxide, potassium hydroxide, and cyclopentanone oxym, to produce magnetite nanoparticles with varying degrees of agglomeration. This agglomeration is believed to be responsible for the formation of mesoporous structures, which are influenced by the pH, the type of base used, the rate of addition of the base, and the drying method. This article was authored by Maria Cristina Mascallo, Yong Bing Pei, and Terry A. Ring.