Magnetic Field Remotely Controlled Selective Biocatalysis

Many applications for medical therapy, biotechnology and biosensors rely on efficient delivery and release of active substances. Here, we demonstrate a platform that explores magnetic-field-responsive compartmentalization of biocatalytic reactions for well-controlled release of chemicals or biological materials on demand. This platform combines two different kinds of core–shell magnetic nanoparticle: one loaded with enzymes and another with substrate-bound therapeutic (bio)chemicals. Both cargos are shielded with a polymer brush structure of the nanoparticle shell, which prevents any enzyme–substrate interactions. The shield’s barrier is overcome when a relatively weak (a fraction of 1 T) external magnetic field is applied and the enzyme and the substrate are merged and forced to interact in the generated nanocompartment. The merged biocatalytic nanoparticles liberate the substrate-bound therapeutic drugs when the enzymes degrade the substrate. The developed platform provides a proof of concept for the remotely controlled release of drugs or (bio)chemicals using the energy of a non-invasive, weak magnetic field.Biocatalysis, if selective, offers great potential for the well-controlled release of drugs and other payloads. Here, Minko and co-workers separate enzymes and substrates by loading them onto individual, polymer-coated nanoparticles, and show that a magnetic field switches on the catalytic activity by merging the polymer shells.