Three-dimensional elemental mapping of hollow Fe2O3@SiO2 mesoporous spheres using scanning confocal electron microscopy

Energy filtered scanning confocal electron microscopy (EFSCEM) in an aberration-corrected transmission electron microscope offers an approach for three-dimensional imaging and chemical analysis of nanoscale materials related to the well-established technique of confocal scanning optical microscopy. Here, we apply EFSCEM to the compositional analysis of the core structure in candidate structures for targeted drug delivery. Element-specific optical sectioning along the specimen depth direction demonstrates the presence of additional Si in a nominal Fe2O3 core. The presence of Si in the core is consistent with a specific formation mechanism for the hollow structure of the core. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714889]