Paper-based enzymatic electrode with enhanced potentiometric response for monitoring glucose in biological fluids

A novel paper-based potentiometric sensor with an enhanced response for the detection of glucose in biological fluids is presented. The electrode consists on platinum sputtered on a filter paper and a Nafion membrane to immobilize the enzyme glucose oxidase. The response obtained is proportional to the logarithm of the concentration of glucose, with a sensitivity of −119±8 mV·decade−1, a linear range that spans from 10−4M to 10−2.5 M and a limit of detection of 10−4.5 M of glucose. It is shown that Nafion increases the sensitivity of the technique while minimizing interferences. Validation with human serum samples shows an excellent agreement when compared to standard methods. This approach can become an interesting alternative for the development of simple and affordable devices for point of care and home-based diagnostics.