Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density

Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer‐modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram‐negative and ‐positive bacteria (E. coli and methicillin‐resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies. Polymer‐modified graphene oxide sheets are presented as novel 2D antibacterial. These polycationic sheets match the size and charge density of Escherichia coli cells, wrap around, immobilize, and slowly kill them. This novel multivalent antibacterial strategy is based on unspecific electrostatic binding and could be employed as adsorber material for bacteria in purification, analysis, or sensor technologies.