There is an invisible but inevitable ingredient that is being served on the tables all around the world: microplastics (MPs). Alarmingly, it is estimated that around 5 g of small sized particles (<1mm) are ingested weekly. These particles can accumulate in the gastrointestinal mucosa, which acts as the first biological barrier encountered by MPs up taken with diet. However, it is yet unknown how the presence of such pollutants affects the physiological functionalities of this highly selective barrier. In this study, a microfluidic setup was used to recreate a MPs contamination at the interface of reconstituted gastric mucus (MUC5AC). For this purpose, 300 nm sized differently charged polystyrene nanoparticles were chosen as a model for natural occurring plastic contamination in the sub-micrometer range.