Tiered testing of micro- and nanoplastics using intestinal in vitro models to support hazard assessments

•Intestinal in vitro toxicity studies mainly use Caco-2, HT29 or HCT116 monocultures.•Cytotoxicity, barrier permeability and transport mechanisms are the main endpoints.•Co-cultures, organ on a chip and organoids might increase the physiological relevance.•Effects involving the microbiome or specific cell types are difficult to assess.•Hazard identification of microplastics in vitro requires a tiered testing approach.