Measuring the Content of a Single Liposome through Electrocatalytic Nanoimpact Titrations

We show the electrochemical determination of attomole glutathione contents within single individual liposomes at low overpotentials through mediated electron transfer by using copper (II) as a catalyst for the oxidation of liposomal glutathione. A titration-like behaviour of individual liposomes was observed when impacting with the electrode to quantify the content within single liposomes. The nanoimpacts titration strategy allows the characterisation of nanoparticles containing redox-inactive molecules at the single-nanoparticle level.