Microplastics and its putative adverse effects on environmental and human health increasingly gain scientific and public attention. Systematic studies on the effects of microplastics are currently hampered by using rather poorly characterised particles, leading to contradictory results for the same particle type. Here, surface properties and chemical composition of two commercially available nominally identical polystyrene microparticles, frequently used in effect studies, were characterised. We show distinct differences in monomer content, ζ-potentials and surface charge densities. Cells exposed to particles showing a lower ζ-potential and a higher monomer content displayed a higher number of particle-cell-interactions and consequently a decrease in cell metabolism and proliferation, especially at higher particle concentrations. Our study emphasises that no general statements can be made about the effects of microplastics, not even for the same polymer type in the same size class, unless the physicochemical properties are well characterised.

微塑料及其对环境和人类健康的假定不利影响越来越受到科学和公众的关注。目前，由于使用特征相当差的颗粒，对微塑料影响的系统研究受到阻碍，导致相同颗粒类型的结果相互矛盾。在这里，表征了在效果研究中经常使用的两种市售名义上相同的聚苯乙烯微粒的表面性质和化学成分。我们在单体含量、ζ 电位和表面电荷密度方面表现出明显的差异。暴露于具有较低 ζ 电位和较高单体含量的颗粒的细胞表现出更多的颗粒-细胞相互作用，因此细胞代谢和增殖减少，尤其是在较高的颗粒浓度下。