Smart integrated sensor for multiple detections of glucose and L-lactate using on-chip electrochemical system

Multiple sensor electrodes,a supplementary electrode,a reference electrode,and signal-processing circuits were integrated on a single chip to develop a chip-shaped electrochemical sensing system. l-lactate and glucose were measured using on-chip working electrodes modified by polyion complex to immobilize lactate oxidase and glucose oxidase,respectively. cyclic voltammetry measurements were conducted using an on-chip potentiostat. selective and quantitative detection of glucose and l-lactate and the interference behavior were studied. hydrogen peroxide generated by enzymatic reactions was detected by an increase in anodic oxidation current. reaction currents at +0.7v versus ag/agcl were used to obtain calibration plots. the measured dynamic ranges for l-lactate and glucose were 0.2-1.0mm and 2.0-8.0mm,respectively. the sensitivities were 65na/mm and 15na/mm,respectively,using a working electrode of 0.5mm2. the 3 detection limit was 0.19mm and 1.1mm,respectively. we have achieved multiple biomaterial detections on a circuit-equipped single chip. this integrated electrochemical sensor chip could be the best candidate for realizing point-of-care testing due to its portability and potential for mass production. © 2011 tomoyuki yamazaki et al.