engleski

Electrode double layer charge displacement by liposome adhesion

Amperometry at the dropping mercury electrode (DME) is proposed as a new analytical method to study liposome adhesion at aqueous interfaces. DME serves as the adhesion sensor [1-3] where the electrical double-layer structure, surface charge density and interfacial tension can be precisely contolled by the applied potential. We present for the first time the electrical signals of liposomes at DME. The electrical signals of liposomes [4] (diameter 1-100  m) are well-defined current transients of ms duration and amplitudes in the range from +3 to – 3  A. At a given potential, amplitude of a signal reflects the liposome size, while the signal frequency depends on liposome concentration. The flow of current is caused by double-layer charge displacement at the mercury/aqueous electrolyte interface due to adhesion and spreading of a single liposome. Adhesion is confined to a broad potential range of positively and negatively charged electrode/ aqueous electrolyte interface (from +11.40 to – 15.32  C/cm2 in 0.1 M NaF). The shape and sign of liposome signals obtained by scanning potentials reveal the predominance of specific electrostatic interactions of fixed charge constituents that are not screend by counterions.

liposome; adhesion; electrical attachment signal; double-layer charge displacement

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