Interaction of cholesterol with artificial bilayer lipid membrane system and development of an electrochemical sensor

Abstract

Interaction of Cholesterol with the bilayer arrangement of phospholipid molecules was studied using electrochemical impedance spectroscopy in Sodium Chloride (NaCl) bath solutions. The membrane resistance (Rm) was decreased from 3.35GΩ in 1.0M NaCl bath to 0.756GΩ in 0.01M NaCl bath. The cholesterol molecules were found to penetrate into Bilayer Lipid Membrane (BLM) and fluidized the BLM phase. Due to fluidization, the membrane resistance was decreased. The fluidization effect of cholesterol was dependent on the concentration of bath solutions. In 1.0M NaCl bath solution, the membrane was stable up to 200µM concentration of cholesterol. With the addition of cholesterol in NaCl bath solutions, the membrane capacitance was increased. An impedimetric sensor was developed based on the membrane resistance in the presence of cholesterol at various concentrations. The detection limit of cholesterol by impedimetric sensor was dependent on the concentration of NaCl in the bath.