Unlike SNPs-18, SNPs-18@BSA induce a gradual shrinkage of the GUVs, which eventually result in considerably smaller vesicles with a thick, crumpled membrane. Realtime confocal microscopy images show that the size of the GUVs decreases over time while their membrane becomes thicker and its fluorescence more intense (Fig ). The increase in membrane thickness and fluorescence intensity likely denotes that SNPs-18@BSA are wrapped and generate highly curved sub-micrometre membrane invaginations. However, these curved membrane buds do not detach from the parent GUV as spots of fluorescence signifying lipid wrapped NPs were not observed in the vesicle lumen. Moreover, nano-sized pores are expected to form on the membrane allowing the contents in the lumen to be expelled from the GUVs while they shrink.