Sweat as energy source using an enzymatic microfluidic fuel cell

An enzymatic microfluidic fuel cell was constructed to produce energy from lactate and oxygen preset in the sweat. In this case, laccase (Lc) connected to anthracene modified carbon nanotubes (An-MWCNT) to facilitate the direct electron transfer (DET) as the biocathode and lactate oxidase (LOx) as the bioanode, both enzymes were immobilized on Toray Carbon Paper (TCP). The oxygen reduction reaction (ORR) showed better results in a pH acid, which agrees with the slightly acid pH of sweat. On the other hand, the Lc showed to have good catalytic activity towards ORR in the presence of sweat, since only about 10% was inhibited after having added 660 µl of sweat. Finally, the enzymatic microfluidic fuel cell was capable to generate 64 µW cm-2 when sweat was fed into both electrodes, this confirms the high selectivity of the LOx and Lc towards lactate oxidation and oxygen reduction, respectively. These results are the first step to design an stamped device to produce energy in real time taking advantage of the sweat produced during workouts. (paper)