Electrochemical Impedance Spectroscopy of Tethered Bilayer Membranes: An Effect of Heterogeneous Distribution of Defects in Membranes

Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles

“…Namely, the presence of defects is manifested by a steplike feature on the total impedance curve and pronounced phase minimum observed at frequency ~1 Hz. However, the phase angle minimum of ~60° is quite shallow, which may indicate the heterogeneous distribution of defects within the membrane [ 42 ]. Such interpretation is supported by AFM results where numerous randomly distributed pinholes of different sizes were observed.…”

Alzheimer's disease-related amyloid β peptide causes structural disordering of lipids and changes the electric properties of a floating bilayer lipid membrane

“…The impedance vs. frequency curves are almost linear for fBLM and fBLM-AbMs, which is typical for capacitive systems. 33 Their respective phase angle vs. frequency plots (Fig. S2b † and 3c) display a plateau with the phase angle values exceeding 80 , thus indicating that the impedance is largely controlled by the membrane capacitance.…”

Electrochemical Biosensors Based on Membrane-Bound Enzymes in Biomimetic Configurations

“…More studies should be done in this direction in order to obtain more stable and specific biosensors for analysis in complex samples. Although sBLMs and tBLMs have shown to be very valuable as model systems for fundamental studies of cell membrane processes [9,25,29,45,48], we think that fBLMs are more adequate for biosensor development. The presence of a water cushion in the interface between the fBLM and the electrode facilitates the insertion of transmembrane proteins in the lipid bilayer and gives higher flexibility and mobility within the biomimetic construction [77,78,82].…”

“…A model that was developed by Valincius et al considering membrane defects has been employed to evaluate changes in capacitance and membrane resistance induced by the incorporation of protein or peptide molecules in the bilayer [47,48]. AFM imaging has allowed for determining the surface morphology of the tBLMs [9] as well as to provide visual images concerning the insertion of the protein or peptide [48]. Despite all of the advantages when compared to sBLMs, tBLMs still do not display long term stability and present a restrictive mobility.…”

“…Floating bilayer lipid membranes (fBLMs) ( Figure 2 c), which interact with the gold substrate by physical interactions, are able to mimic the quasi natural environment of real membranes. They show better lateral mobility of the bilayer [ 48 ] and reduce the risk of protein denaturalization, thus preserving it activity. fBLMs are composed by a bilayer that floats ∼2.4 nm over a supporting layer on the surface [ 21 , 49 ] or a monolayer of S-layer protein [ 50 ].…”