A biological/electrochemical reservoirs integrated microsensor for the determination of biochemical oxygen demand

In this paper, a novel Biochemical Oxygen Demand (BOD) microsensor consisted of a biological reservoir and an electrochemical reservoir was fabricated by Micro Electro-Mechanical System (MEMS) technology. The consumption of Dissolved Oxygen (DO) is occurred in biological reservoir by respiration of the microbial, and the change of DO was detected in the electrochemical reservoir by the integrated microelectrode array (MEA). Because of the hemispherical diffusion mode of the MEA, the increase in current densities, the enhancement in mass transport and the increase in signal-to-noise ratios were displayed. The fabricated microsensor showed linear response to DO ranging from 0.5 mg/L to 7.2 mg/L and linear response to BOD ranging from 0 to 20 mg/L. The satisfied results showed that the miniaturized BOD microsensor can be used to detect BOD in the solution, and this method can be applied in other microsystem fabrication.