In Situ and Individual-Based Analysis of the Influence of Polystyrene Microplastics on

The impact of microplastic particles of micro- and nanometer sizes on microbial horizontal gene transfer (HGT) remains a controversial topic. Existing studies rely on traditional approaches, which analyze population behavior, leading to conflicting conclusions and a limited understanding. The present study addressed these limitations by employing a novel microfluidic chamber system for in situ visualization and precise quantification of the effects of different concentrations of polystyrene (PS) microbeads on microbial HGT at the single-cell level. The statistical analysis indicated no significant difference in the division times of both the donor and recipient bacteria across different PS microbead concentrations. However, as the concentration of PS microbeads increased from 0 to 2000 mg L