A novel biofuel cell harvesting energy from activated human macrophages.

Macrophage phagocytosis activates NADPH oxidase, an electron transport system in the plasma membrane. This study examined the feasibility of utilizing electrons transferred through the plasma membrane via NADPH oxidase to run a biofuel cell. THP-1 human monocytic cells were chemically stimulated to differentiate into macrophages. Further they were activated to induce a phagocytic response. During differentiation, cells became adherent to a plain gold electrode which was used as anode in a two-compartment fuel cell system. The current production in the fuel cell always corresponded to the NADPH oxidase activity, which was evaluated by the amount of superoxide anion produced upon stimulation in combination with the expression levels of the different NADPH oxidase subunits in cells. Moreover, our results of different inhibitory tests let us conclude that (i) the current observed in the fuel cell originates from NADPH oxidase in activated macrophages and (ii) there are multiple electron transport pathways from the cells to the electrode. One pathway involves superoxide anions produced upon stimulation, additional not yet identified electron transport occurs independently of superoxide anions.This type of novel biofuel cell driven by living human cells may eventually develop into a battery replacement for small medical devices.

Label-free detection of Babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated flow cytometer.

Impedance spectroscopy is a powerful tool for label-free analysis and characterisation of living cells. In this work, we achieved the detection of Babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated flow cytometer. The cellular modifications caused by the intracellular parasite result in a shift in impedance which can be measured dielectrically. Thus, a rapid cell-by-cell detection with microliter amounts of reagents is possible. Unlike other diagnostic tests, this method does not depend on extensive sample pre-treatment or expensive chemicals and equipment.