Electroresponsive Supramolecular Graphene Oxide Hydrogels for Active Bacteria Adsorption and Removal

Bacteria contamination in drinking water and medical products can cause severe health problems. However, currently available sterilization methods, mainly based on the size-exclusion mechanism, are typically slow and require the entire contaminated water to pass through the filter. Here, we present an electroresponsive hydrogel based approach for bacteria adsorption and removal. We successfully engineered a series of graphene oxide hydrogels using redox-active ruthenium complexes as noncovalent cross-linkers. The resulting hydrogels can reversibly switch their physical properties in response to the applied electric field along with the changes of oxidation states of the ruthenium ions. The hydrogels display strong bacteria adsorbing capability. A hydrogel of 1 cm³ can adsorb a maximum of 1 × 10⁸ E. coli. The adsorbed bacteria in the hydrogels can then be inactivated by a high voltage electric pulse and removed from the hydrogels subsequently. Owing to the high bacteria removal rate, reusability, and low production cost, these hydrogels represent promising candidates for the emergent sterilization of medical products or large-scale purification of drinking water.