Performance of an electrochemical sensor with different types of liposomal mediators for the detection of hemolytic bacteria

A novel electrochemical method for the selective detection and enumeration of hemolytic bacteria was investigated by using different types of liposomal mediators. The hemolytic actions toward liposomes and the reducing action of bacteria on the mediator 2,6-dichlorophenolindophenol (DCPIP) were used as the basis of an amperometric measuring system. When three types of liposomal mediators including mediator-entrapped single unilamellar vesicles (SUVs), mediator-entrapped multilamellar vesicles (MLVs), and mediator-intercalated SUVs (DI-SUVs) were examined in a simple electrochemical cell, all of those liposomal mediators showed selectivity toward hemolytic bacteria, including Listeria monocytogenes. Correlations between initial rate of currents and bacterial concentration in the range of 5 × 105 to 2 × 107 cfu ml−1 were established by using DI-SUVs and a working electrode poised at 0.3 V (versus reference), pH 7.0, and a temperature of 30 °C.