Bacteriophage-Templated Assembly of Magnetic Nanoparticles and Their Actuation Potential

Magnetic chains are of fundamental and technological interest. However, 1D assemblies of magnetic nanoparticles are only metastable such that their controlled organization requires the use of templates. Bacteriophages are human-inoffensive viruses with a filamentous morphology that have been shown to exhibit great potential in materials research. Here, we thus utilized the M13 phage as a model for the formation of actuated magnetite nanoparticle superstructures. First, we built a sperm-like ensemble by covalently attaching magnetic nanoparticles to the head of the phage. Second, chain-like assemblies are obtained based on the electrostatic interactions between positively-charged magnetite nanoparticles attached to the negatively-charged phage surface. The nanoparticles-phages assembly is steered by external magnetic fields. We anticipate such materials can find applications in nanotechnology or nanomedicine.