Electrochemical Behaviors Of Lipid Bilayers Absorbed On Self‐assembled Monolayers On Gold

Cell membrane is a kind of carrier for the exchange of matter, energy and informationbetween inside and outside of a cell. Therefore, it is important to study the properties of amembrane for understanding some life processes. People often adopt hybrid bilayermembranes or hybrid self-assembed monolayers as models of cell membranes, to study theionic channel, trans-membrane electron transfer and drug delivery through the interactionsbetween ion, molecules or nanoparticles, and them. Meanwhile, the combination ofelectrochemical technique with the self-assembed membranes provides a wonderfulopportunity to study many fundamental problems of biomembrane, for example, thedynamic mechanism of the trans-membrane electron transfer, adsorption and desorptionprocesses, the defects of a membrane, to name a few.This thesis mainly consists of two parts. In the first part, the electrochemicalbehaviors of octadecanethiol （OTS） monolayers and hybrid monolayers composed ofoctadecanethiol and cysteamine were studied. The electrochemical characteristics of thefilms were investigated by both cyclic voltammetry and electrochemistry impedancemethods. It is shown that a compact film has formed on the electrode in24h. In contrast tothe OTS monolayers, the cysteamine in the hybrid monolayers makes the Fe（CN）₆^3-/4-probe reach the electrode surface easier. Furthermore, the impedance spectroscopy can beinterpreted in terms of an equivalent circuit based on the dot corrosion model of adouble-component monolayer. A series of pH values of the Fe（CN）₆^3-solution wereemployed in the experiment, which demonstrated a better CV behavior of the film in acidconditions compared with the alkaline cases.In the second part, the interactions between the hybrid bilayer membranes （HBMs） composed of octadecanethiol and lipid with Ca²⁺or mesoporous silica nanoparticles （MSN）were investigated, by the methods of cyclic voltammetry and quartz crystal microbalance.It was shown that with the increase of Ca²⁺concentration, the capacitance of the HBMsincreased; however, with the same Ca²⁺concentration, the capacitance of the HBMsincreased slightly with the immersion time of the electrode in the CaCl₂solution. It wasfound that the changing pH values （from3to10） hardly affected the property of the HBMs.The interactions between the HBMs and the amino-modified MSN was found the strongestat pH5, however, when the carboxyl-modified MSN were exposed to the HBMs, nosignificant deviations were observed at various pH values.