Positioning Formation and Controllable Fabrication of Lipid Vesicles Using Patterned Substrates

Trimethoxy-(octadecyl)-silane (TODS) was self-assembled on the surface of conductive indium tin oxide (ITO) substrates, and a patterned substrate with distinct hydrophilic and hydrophobic regions was constructed via deep ultraviolet (UV) light (254 nm) etching. The effect of this patterned substrate on lipid vesicle (LV) formation was investigated by using electroformation. Experimental results demonstrated that fluorescence-labeled LVs exhibited bright and dark regions corresponding to the mask design. Specifically, the UV-etched areas were hydrophilic, showing a high fluorescence intensity and a dense population of LVs. In contrast, the unetched regions coated with TODS remained hydrophobic, exhibiting low fluorescence intensity and minimal or no vesicle formation. The presence of bright and dark regions on the substrate, along with the distribution and localization of LVs in these regions, was systematically analyzed. Additionally, the reasons for the varying degrees of vesicle formation within the same dark region were discussed. Through precise surface modification and controlled patterning, it is anticipated that localized formation and spatial regulation of LVs can be achieved.