Biofilms, which can occur in various places in the human body, can cause a range of infections. Made of microbes encased in a matrix that makes them resistant to external threats, they are notoriously hard to shift, especially when they accumulate on the surface of medical implants. New devices called “magnetic hydrogel micromachines”, developed by a CUHK team, are formidable weapons to resist and overcome the biofilm menace. It can be controlled by magnets, to precisely target the biofilm for removal.