Based On Carbon Nanotubes Attached To Pairs Of Enzyme System Of Lactic Acid Electrochemiluminescence Biosensor

This paper studied the application of luminol's electrochemiluminescent (ECL) in enzymatic reaction in alkaline solution. Because of H2O2 produced by enzymatic reaction can increase the ECL of luminol, with this it can be used to fabricate different enzyme biosensor. It can detect the lower concentration of samples due to the highly sensitivity of ECL and highly selectivity of enzyme.The first part studied the fabrication of Dual enzyme biosensor with Pt electrode. An ECL-based Lactic acid (LA) biosensor is developed which signaled with luminol. LA could be oxidized under the catalysis of immobilized lactic dehydrogenase (LDH) and pyruvate oxidase (PyOD) to produce hydrogen peroxide with nicotinamide adenine dinucleotide (NAD) as coenzyme. The enzymatic generated hydrogen peroxide can enhance the ECL intensity of luminol. The ECL-based biosensor showed excellent character for LA measurement. Its linear detection limit decreased to 8.9×10-12mol/L with relative standard deviation of 4.13% (CLA 1.34×10-10mol/l, n = 6) and average recovery of 101.3%. This ECL-based LA biosensor has reached a lower detection limit. It can be applied to detect the concentration of LA in the sweat of athletes during the exercitation for evaluation of exercise degree, and get a good result.The second part studied that the ECL mechanism of luminol on ITO electrode in the alkaline solution.The results indicated that the phenomenon that ECL of luminol on the ITO electrode could occurre under a lower voltage, and ITO was cheap and convenient. We modified the Dual enzyme in the ITO electrode, obtained satisfactory results, high reproducibility, and good stability.