Enzyme-containing nanoparticle. Illustration of the structure of a possible nanoparticle design for use in biocatalysis. This nanoparticle consists of a magnetic core (purple, lower left) and a polymer brush exterior (pink strands). The mobile enzyme vesicles (blue sphere) are shown in the polymer brush scaffold. Such nanoparticles could be used to deliver enzymes designed to catalyse biochemical reactions.