In order to study the interaction between different neurotransmitters and the vesicle membrane, we chose to study dopamine-loaded vesicles (DLL) and serotonin-loaded vesicles (SLL). These are both transmitters that are widely distributed in the nervous systems of mammals. These transmitters were loaded into liposomes of similar size as a model of biological vesicles without proteins and cargo with different membrane adsorption properties. The preparation process followed our previous work. Briefly, a mixed solution of phospholipids in chloroform was dried and formed a lipid film in a round-bottom flask. The lipid film was then hydrated in a hydration solution containing 150 mM DA or 5-HT, To prepare a population of DLL or SLL with various sizes. The sizes of vesicles were narrowed by use of reciprocating extrusion through double polycarbonate filter membranes in the same hydration solution and were measured to be 188 nm (polydispersity index=0.13) as the average radius via dynamic light scattering (see more details in Supporting Information). The DLL or SLL are stable in isotonic solution. To trigger and record the release of contents, VIEC was used according as described previously 33 (see Figure , and more details in Supporting Information). When a vesicle settles on the electrode, the high electric field near the surface induces electroporation of the liposome membrane allowing the contents to diffuse out through the pore in membrane at the electrode surface. Released DA and 5-HT are rapidly electrooxidized at the electrode generating a spike shaped current. Using Faraday's law, the charge passed for each current spike (Q, the charge) is proportional to the number of molecules oxidised. In addition, the dynamic parameters of each spike, including the rise time (t rise ), fall time (t fall ), and width at half spike height (t half ) can be used to evaluate release dynamics. 17