To build the nano-sized robots (10 of them lined up would span a red blood cell), researchers attached catalase enzymes to porous silica ... increase over passive diffusion of particles.

Colloids and Interfaces, Transport in porous/nonporous materials ... was enabled by these methods involves the ubiquitous intermittent motion (i.e. “hopping diffusion”) of molecules at interfaces, ...

Metal-organic frameworks (MOFs), recognized as ideal enzyme immobilization carriers owing to their high surface area and tunable porous structures, have been of considerable research interest.