The Research Of Electroimmunoassay Based On Heated Carbon Paste Electrode

With the development of the immunoassay, enhancing the sensitivity of immunoassay has become the common purpose of scientists. Heated carbon paste electrode (HCPE) technique is a fantastic way to accelerate reaction kinetic and, at the same time, improve the mass transport by changing temperature of electrode, thus leading to an enhanced electrochemical signal together with an higher signal-to-background ratio. Besides, the HCPE is of symmetric design and the 100kHz alternating current (AC) generated from a function generator is used to heat the electrode with no effect on the current response of the sensor, which has been testified theoretically and experimentally. At the same time, the apparatus of HPCE is very simple and environment friendly. In this thesis, HCPE was used in the construction of immunosensors, besides, novel immuno-lables and platform materials were also used in the immunoassays, which greatly improved the sensitivity of the prepared immunosensors. The main results were summarized as follows:1.Ultrasensitive immunoassay based on dual signal amplification of the electrically heated carbon electrode and quantum dots functionalized labels for the detection of MMP-9we developed a novel dual amplification method for sandwich immunosensor through combing the heated-electrode technique with QDs funcitionalized electroacitve labels to detect MMP-9. A super biocompatible and thermal steady material, carbon nanotube-doped Polypyrrole (MWNTs-PPy), was chosen to immobilize proteins. The proposed biosensor exhibited attractive advantages of ease of performance, high sensitivity and specificity for the ultrasensitive detection of MMP-9, revealing great potential towards early evaluation of cancer therapeutic effects.2. Ultrasensitive immunoassay of Human Interleukin 6 using a competitive immunosensor based on the electrically heated carbon electrode and silver nanoparticles functionalized labelsA facile one-step electrochemical reduction method was developed to prepare ERGO-AuPdNPs as the platform of immunosensor. The resulting hybrid material incorporated both the high-binding capability of grapheme nanosheets, favorable biocompatibility of gold and palladium nanopaticles. A novel competitive electrochemical immunoassay was then proposed by combing the ERGO-AuPdNPs platform with silver nanoparticles functionalized PS labels for the sensitive detection of human interleukin 6. An electrically heated carbon electrode was induced in the detection procedure of the immunosensor, and further improved the sensitivity. The immonosensor exhibited a wide linear response to IL-6 ranging from 0.1 to 10000 pg mL-1 with a detection limit of 0.059 pg mL-1. The proposed method showed good precision,acceptable stability and reproducibility, and could be used for the detection of IL-6 in real samples, which possessed promising application in clinical research.