Highly sensitive non-enzymatic lactate biosensor driven by porous nanostructured nickel oxide

Lactate sensors are increasingly used for applications in sports and clinical medicine, but currently have several shortcomings including low sensitivity. We demonstrate a highly sensitive and selective non-enzymatic lactate sensor based on porous nickel oxide by sol-gel based inverse micelle method. The porosity and surface area of nickel oxide depending on the calcination temperature (250, 350, and 450 degrees C) were compared using electron microscopy and a Brunauer-Emmett-Teller (BET) surface area analyzer. Furthermore, we also compared the chemical state of Ni3+ in porous nickel oxides, which is known to be strongly engaged with electrocatalytic lactate detection, with different calcination temperature. The sensing characteristics were assessed using an amperometric response with a three-electrode system. Owing to a relatively large surface area and high Ni3+/Ni2+ ratio, NiO calcined at 250 degrees C, exhibit maximum sensitivity at 62.35 mu A/mM (cm(2)), and a minimum detection of limit of 27 mu M, although, it has large amount of organic residue because of low calcination temperature. In addition to its sensitivity, a porous nickel oxide electrode also displays good selectivity against other interferents such as L-ascorbic acid, uric acid, and dopamine, further supporting its potential as a non-enzymatic lactate sensor.