(a) Schematic of preparing platelet membrane-coated Si particles. (b) Detection of membrane protein-associated lipid layer in discontinuous sucrose gradient solution by dot blot assay. Lipid fractions were identified as translucent layers in between two sucrose concentrations. (c) SEM and TEM characterization. SEM images: (1) Activated platelets, (3, 5) APTES-Si particles, (4, 6) PMDV-coated Si particles. TEM images: (2) PMDVs, (7) APTES-Si particles, (8) PMDV-coated Si particles. Arrow head identifies the hollow structure of PMDVs.