Dynamic remodeling of pipe material interfacial properties: Intervention effects on biofilm in water distribution...

Biofilm contamination in water distribution networks (WDNs) persistently threatens water safety and operational efficiency, representing a critical public health challenge. Herein, we develop an environmentally adaptive, pH-responsive, and non-leaching antibacterial coating strategy to construct a durable bio-safe interface on pipe walls. Leveraging polydopamine (PDA) for robust interfacial adhesion, the coating incorporated chitosan and gelatin to form a stable composite layer. The engineered surface exhibited superhydrophilicity, low roughness, and elevated total pipe-bacteria interaction energy (ΔG^TOT), and reversible surface charge switching in response to pH variations. Such features enable environmentally triggered antibacterial responses, enhancing both bacterial repulsion and inactivation. Owing to its positively charged and structurally disruptive interface, the coating synergized with free chlorine (Cl₂) to potentiate antimicrobial efficacy. Under long-term flow conditions simulating actual WDNs operation, this combination achieved up to a 3-log reduction of adhered bacteria, effectively delaying colonization and suppressing biofilm matrix formation. Multi-omics analyses revealed that the coating molecularly inhibited biofilm establishment by downregulating key pathways such as quorum sensing, simultaneously limiting microbial exchange between the water and biofilm phases, thereby promoting pronounced inter-phase community divergence. This study establishes a new paradigm for constructing bio-safe interfaces and safeguarding water supply reliability.