Magnetic Hydrogel Micromachines with Active Release of Antibacterial Agent for Biofilm Eradication

Bacterial biofilms are widely found in nature, and they can be a major factor in many local chronic infections inside the human body. To date, effective elimination of biofilms is intractable for conventional antibiotic therapies due to the existence of bacteria‐protecting extracellular polymeric substances. For biofilm eradication in tiny tubular structures, magnetic hydrogel micromachines (MHM) are designed that are capable of performing mechanical disruption of biofilms while releasing antibacterial agents in a controllable fashion. Two modes of motion controlled by external magnetic fields, namely planar rotation and wobbling modes, have been investigated to drive the micromachines to interact and destruct biofilms. In addition, the presented micromachines are composed of thermosensitive PNIPAm hydrogel that can load with the antibacterial agent (H2O2) and release them upon heating. The Fe3O4 nanoparticles embedded in the hydrogel matrix act as catalysts for the Fenton reaction, generating bacteria‐killing free radicals. The synergetic biofilm elimination effect has been experimentally demonstrated in well plates and small tubes. The presented MHMs may provide a new design to treat biofilm‐related infections in narrow and confined spaces.