Cu-containing stainless steel target quorum sensing to interfere with bacterial motility

• Cu-containing stainless steel can modulate bacterial motility trajectory. • Cu-containing SS interferes with bacterial motility through QQ effect. • Cu-containing stainless steel can target QS interfering bacterial motility to inhibit biofilms . Biofilms have been known to cause contamination of drinking water and reduce the efficiency of wastewater treatment. Despite there are many strategies about reducing surface adhesion or killing bacteria, stubborn biofilms are difficult to eradicate completely and still cause continuous contamination because of the difficulty to find comprehensive and effective targets. Here, we identify a new role for quorum sensing (QS) in regulating bacterial motility during biofilm development. We proposed a mechanism of quorum quenching (QQ) by Cu-containing stainless steel (SS), aiming to interfere bacterial motility which associated with surface-attached bacteria self-organizing into microcolonies in early biofilm and the growth and extension of developmental biofilm. A parallel cell-tracking process was conducted to extract the motility history of multiple cells on a newly colonized surface and movement trajectories of biofilm maturation in situ real-time. Results showed Cu-containing SS enhanced bacterial motility of early biofilm, therefore weakening the colonization. Moreover, the development of bacterial community self-organization was retarded by reducing “trajectory cross-over” during the mature stage. Using engineered strains with deleted QS signal, we confirmed QS played a key role in determining bacterial motility. The QQ by Cu-containing SS ultimately guided bacterial motility towards an unfavorable trend for biofilm development.