Liquid-bodied antibiofilm robot with switchable viscoelastic response for biofilm eradication on complex surface topographies.

Recalcitrant biofilm infections pose a great challenge to human health. Micro- and nanorobots have been used to eliminate biofilm infections in hard-to-reach regions inside the body. However, applying antibiofilm robots under physiological conditions is limited by the conflicting demands of accessibility and driving force. Here, we introduce a liquid-bodied antibiofilm robot constructed by a dynamically cross-linked magnetic hydrogel. Leveraging the viscoelastic response of the robot enables it to adapt to complex surface topographies such as medical meshes and stents. Upon actuation, the robot can mechanically destroy the biofilm matrix, chemically deactivate bacterial cells, and collect disrupted biofilm debris. The robot's antibiofilm performance is studied in vitro and demonstrated on a medical mesh and a biliary stent. Tracking and navigation under endoscopy and x-ray imaging in an ex vivo porcine bile duct are demonstrated. Last, in vivo antibiofilm treatment is conducted by indwelling infected stents into mice's abdominal cavity and clearing the biofilm infection using the proposed robot.