Mechanized Silica Nanoparticles Based on Pillar[5]arenes for On-Command Cargo Release

Mechanized silica nanoparticles, equipped with pillar[5]arene‐[2]pseudorotaxane nanovalves, operate in biological media to trap cargos within their nanopores, but release them when the pH is lowered or a competitive binding agent is added. Although cargo size plays an important role in cargo loading, cargo charge‐type does not appear to have any significant influence on the amount of cargo loading or its release. These findings open up the possibility of using pillar[n]arene and its derivatives for the formation of robust and dynamic nanosystems that are capable of performing useful functions.