Membrane fluidity of tetramyristoyl cardiolipin (TMCL) liposomes studied by chronoamperometric monitoring of their adhesion and spreading at the surface of a mercury electrode

Abstract

Giant unilamellar liposomes of the synthetic cardiolipin 1′,3′-bis[1,2-dimyristoyl-sn-glycero-3-phospho]-snglycerol give chronoamperometric current peaks at a stationary mercury electrode. The signals are due to the adhesion and spreading of the liposomes on the hydrophobic mercury surface. The potential dependence shows a minimum of the peak frequency at the point of zero charge, a large maximum of peak frequency at about −0.2 V and a second, however, smaller maximum at −0.8 V. The electrochemical behaviour of the liposomes indicates phase transitions of the cardiolipin which could be also observed in differential scanning calorimetry.

The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

“…Since the addition of 2.2 µmole all-trans MK-4 to TMCL has practically no effect on the phase transition temperatures of TMCL (40.7 °C and 23.8 °C) ( Fig. S1) determined previously in a chronoamperometry study (Zander et al 2012), it can be assumed that the two components do not form specific phases, and further, that the menaquinone does not alter the TMCL phases. Natural cardiolipins (nCL) and nCL containing all-trans MK-4 liposomes do not exhibit any phase transitions in the temperature range 7 to 90 °C.…”

The theory of metal electronucleation applied to the study of fundamental properties of liposomes

“…Analysis of macro-kinetic data (number of adhesion spreading events over time per surface area and how it changes with temperature) has been proven useful to perform qualitative studies of real cell membranes, such as thrombocytes and mitochondria, as well as to study the effect of foreign molecules and the liposome composition on the membrane properties [25][26][27][28]. what would be expected both from a pure diffusion- (Fig.…”