Electrochemical impedance spectroscopy for detection of parasites in drinking water

We present here a new, label-free, real time and non-invasive method to detect parasites infecting water and quantify their concentration by Electrochemical Impedance Spectroscopy (E.I.S.). As far as we know, it is the first time parasites are directly detected by E.I.S.. This work comes within the scope of world water crisis whose one of main obstacles is parasite infection. As a model for waterborne parasite, Cryptosporidium parvum is studied. Sensors consist in interdigitated microelectrodes. It is shown that parasite detection requires low conductive buffer. Impedance spectrums from parasites suspended with various concentrations in purified water are fitted with an electric circuit to extract sample conductance. Sample conductance increases linearly with parasite concentration. This relation shows E.I.S. enables to know parasite concentration and can be used in water treatment process. A new method to achieve total diagnosis by identifying dead and living parasites is also presented.