In Situ Amperometric Characterization of Liposome Suspensions with Concomitant Oxygen Reduction

Amperometry of oxygen reduction at the dropping mercury electrode (DME) was applied for in situ characterization of liposome suspensions in terms of concentration, level of polydispersity and potential range of adhesion. Liposomes prepared from egg‐phosphatidylchloline/cholesterol/dicetylphosphate in the molar ratio of 7 : 5 : 1 were suspended in phosphate‐buffered saline (PBS). Adhesion signals of single liposomes in air‐saturated suspensions were detected in the broad potential range (from −100 to −1200 mV vs. 0.1 M Ag/AgCl reference electrode) as transient enhacements of oxygen reduction. Measured concentration range in air‐saturated suspensions was 106–108 liposomes/L.