Table 2.

Comparison between conventional and controlled DDS. Created based on information from [12, 13]

Layer	Role
Surface layer	▪ The outermost layer that can be functionalized to allow the attachment of different entities ( i.e. , metal ions, small molecules, surfactants); ▪ NP’s interactions with its environment are mostly determined by the functionalized surface.
Shell layer	▪ Lying below the surface layer; ▪ It affects the NP’s general characteristics, acting as a barrier, and also affecting the stability, biocompatibility, and interactions of the NP with its surroundings.
Core	▪ Vital section of the NP located in its center; ▪ Determines the basic characteristics of the NP and is frequently used interchangeably with the particle itself; ▪ Influences the optical, magnetic, or catalytic properties of the NP.

DDS: Drug delivery systems; NP: Nanoparticle