Bacteria-nanoplastic interactions: mechanisms, ecological consequences, and advances in biodegradation technologies.

Nanoplastics (< 1 μm) represent a pervasive class of environmental contaminants with unique physicochemical properties that profoundly influence microbial ecosystems. Their high surface-area-to-volume ratio, weathering-induced functionalization, and ability to adsorb chemical pollutants and biomolecules facilitate intricate interactions with bacterial communities. This review systematically examines nanoplastic-bacteria interactions, highlighting mechanisms such as oxidative stress induction, membrane perturbation, DNA damage, metabolic reprogramming, biofilm modulation, and enhanced horizontal gene transfer, which collectively reshape microbial structure and function. Emphasis is placed on the plastisphere microbiome as a dynamic hotspot for pollutant accumulation, pathogen enrichment, and resistance gene exchange. Bacterial biodegradation pathways, including enzymatic hydrolysis, oxidative processes, biosurfactant-mediated interactions, and multispecies consortia activity, are analyzed in detail. Advanced analytical tools, such as nanoscale imaging, spectroscopy, flow cytometry, meta-omics, and AI-assisted computational modeling, are discussed for their role in elucidating nanoplastic-microbe dynamics. Environmental and human health implications, including microbiome disruption, immunotoxicity, and ecological perturbations, are evaluated. Finally, emerging biotechnological strategies for enhancing biodegradation are explored, and critical research gaps are identified. This review provides a comprehensive framework for understanding nanoplastic-bacteria interactions, offering strategic insights for environmental monitoring, risk assessment, and bioremediation development.