Fig. 4

Internalized PS-NH₂ formed lipids packing nanoplastics. a Confocal laser scanning microscopy on the localization and morphology of fluorescently labeled PS-NH₂ (green) and membrane lipids (red) in bacteria following exposure to PS-NH₂ (80 nm) for 3 h. Control, bacterial cells in the absence of PS-NH₂. Merge, an overlap of the images of lipids stained by Dil and PS-NH₂. Scale bars, 1 μm. b Molecular dynamics simulations of PS-NH₂ (16 nm) uptake by the mimic membrane bilayers. Top panel, front view; Bottom panel, top view. c Confocal laser scanning microscopy of 2 μm PS-NH₂ coated with lipids. The nanoparticles were incubated with or without a lipid mixture containing phospholipids in fatty acids. Dil dye was used for staining the phospholipid layer. SEM image was also recorded to show the different textures between the pure PS-NH₂ and PS-NH₂ coated with lipids. Scale bars, 2 μm. d Confocal laser scanning microscopy of the interaction and morphology of 2 μm PS-NH₂ with a synthetic unilamellar liposome following incubation for 15 min. Scale bars, 2 μm. e Time course of morphology changes of the macro artificial lipid membrane by dripping 1 µL PS-NH₂ (80 nm) from the top. The artificial lipid membrane (radius ≈ 0.5 cm) was constructed by dripping a drop of the mixture of phospholipids and fatty acids on the surface of deionized water in a plate (Additional file 1: Fig. S12). Scale bars, 5 mm. f Morphology changes of the artificial lipid membrane by dripping 1 µL PS-NH₂ (80 nm) from the membrane boundary. Control, lipid membrane in the absence of PS-NH₂. The red arrow indicates the internalized PS-NH₂. Scale bars, 0.3 mm