Quorum sensing on microplastics shapes biofilm function in wastewater systems

Microplastics (MPs) in wastewater treatment plants (WWTPs) represent novel ecological niches rather than passive contaminants. They rapidly acquire distinct microbial biofilms, forming the “Plastisphere”. This Perspective examines the underexplored role of quorum sensing (QS) within these complex synthetic microenvironments. We highlight how the intrinsic properties of MPs, such as surface hydrophobicity, chemical leachates, and aging states, create altered signaling landscapes. These distinct environments may decouple QS responses from classical population-density thresholds. Consequently, these dynamic interactions potentially enhance cooperative microbial metabolism and may indirectly facilitate the horizontal gene transfer of antibiotic resistance genes by fostering dense cellular proximity. Despite substantial methodological challenges in detecting active signaling in situ, MPs must be reconceptualized as quorum-modulating microscopes capable of reprogramming microbial communication. Advancing this field requires integrating high-resolution spatial imaging and functional genomics under operationally relevant conditions to bridge theoretical insights with empirical validation, ultimately informing future treatment designs and environmental risk assessments. Microplastics intensify quorum-sensing-mediated gene exchange in wastewater treatment plants, enabling their reconceptualization as quorum-modulating microscopes that reprogram microbial communication and function, based on their interplay with biofilms and quorum sensing within wastewater systems