Integrated Self-Powered Microchip Biosensor for Endogenous Biological Cyanide

Abstract

In this work we developed a fully integrated biofuel cell on a microchip, which consisted of glucose dehydrogenase supported (carbon nanotubes/thionine/gold nanoparticles)₈ multilayer as the anode, and the (carbon nanotubes/polylysine/laccase)₁₅ multilayer as the cathode. The as-obtained biofuel cell produced open circuit potential 620 mV and power density 302 μW cm⁻², showing great potential as a small power resource of portable electronics. Most importantly, for the first time we demonstrated the feasibility of developing a self-powered biosensor based on the inhibitive effect on microchip enzyme biofuel cell. With cyanide employed as the model analyte, this method showed a linear range of 3.0 × 10⁻⁷ to 5.0 × 10⁻⁴ M and a detection limit with 1.0 × 10⁻⁷ M under the optimal conditions. The detection limit was lower than the acceptable cyanide concentration in drinking water (1.9 × 10⁻⁶ M) according to the World Health Organization (WHO). This self-powered sensor was successfully used to detect the cyanide concentration in a real sample, cassava, which is the main carbohydrate resource in South America and Africa. This presented biosensor combined with a resistor and a multimeter demonstrated the general applicability as a fast and simple detection method in the determination of endogenous biological cyanide.