A wide variety of nanomaterials have been used as core materials for the subsequent construction of nanomedical systems. The core material is important in terms of the detection technologies that can be used for diagnostics. The core building blocks of a nanomedical system can have both structural and functional attributes. Structurally, it is a starting point for building multilayered nanomedical systems with a combination of genes or drugs, targeting molecules, and stealth molecules to evade the immune system in vivo. It is also the starting place in the manufacturing process.