Electrochemical Impedance Spectroscopy Based Evaluation of Chlorophyll a Reconstitution within Tethered Bilayer Lipid Membrane

Abstract

This article reports electrochemical impedance spectroscopy-based evaluation of chlorophyll a (Chl-a) reconstitution within tethered bilayer lipid membrane (tBLM), formed on a gold surface by vesicle fusion. The self-assembled monolayer (SAM) consisting of a mixture of WC14 (20-tetradecyloxy-3,6,9,12,15,18,22-heptaoxahexatricontane-1-thiol) and β-mercaptoethanol (βME) mixed in a molar % ratio of 35:65 served as a molecular anchor for tBLMs. The fluorescence microscopy (FM) allowed direct observation of incorporation of Chl-a into membranes. The lipid composition consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol (Chol), was found to be highly compatible with the addition of Chl-a to the phospholipid membranes at different molar ratios. Moreover, the addition of Chl-a to DOPC yielding DOPC (50%)/Chol (40%)/Chl-a (10%) bilayers consistently decreased defect density in tBLMs, thus increasing dielectric integrity of the membranes. Also, we observed a significant structural stabilization of tBLMs subject to bias potential variation in experiments involving Chl-a containing bilayers.