Fig. 5: Interfacial interaction between GOs and the phospholipids on the outer layer of LDL.

a Morphological images of LDL and GO/LDL complexes observed by AFM. Scale bar represents 500 nm. b, c X-ray liquid interface scattering results of structures between phospholipid (SOPC) and GOs. b XRR data of GOs adsorption and the SOPC thickness. c Electron density profiles derived from the XRR data in b. POPC self-assembles to form a monolayer on the air-water surface and GOs at 20 μg/mL are incubated with SOPC monolayer under a surface pressure of 20 mN/m for XRR characterization. d–f Molecular interaction between graphene or GO nanosheets and a model lipid droplet (representing LDL particles) based on coarse-grained molecular dynamics. d Schematic diagrams showing the structure of a lipid droplet. The outer layer of the lipid droplet includes POPC monolayer (in cyan) and free cholesteryl (in orange). The inner components contain cholesteryl ester (in yellow) and triglyceride (in red). e Snapshots of the lipid droplet structure depositing on graphene and GOs. For the GO models, the hydrophilic carbon is assigned as carbonyl groups, while the hydrophobic carbon is assigned as sp² and sp³ carbon. For graphene (GRA), GO1, and GO2, the percentage of carbonyl carbon among all carbons is assigned as 0, 30%, and 50% beads, correlating to the hydrophilicity of pristine graphene, L-GO, and H-GO, respectively. f Illustration of POPC lipids at the edge of lipid droplet bound to graphene/GOs. Each panel contains 40 POPC molecules. g–j Density profiles of the lipids along the vertical direction to graphene/GOs. k–n Interaction energy between the lipid components and the graphene/GOs. Each simulation is performed for at least 2 μs when the interaction energy between POPC and the graphene/GOs increases slowly, indicating that no more POPC molecules spread on the surface. Source data are provided as a Source Data file.