Study On Electrochemical Immunosensor For Detection Of Transgenic Protein Cry 1Ab

Recently, the rapid development of genetically modified crop brings us a lot of benefits as well as problems, such as environmental issues and health issues. Therefore, developing a rapid technology to achieve its detection is in urgent need. Electrochemical immunosensor has developed very quickly. Compare to other methods, this method has advantages of high sensitivity, short detection time, low cost and easy operation, and has great potential in the detection of genetically modified crops. Therefore, this study using electrochemical immunosensor to achieve quantitative detection of Cry lAb, which is a common protein in genetically modified crops.Firstly, an electrochemical assay of a steady and dynamic detection method of alkaline phosphatase (AP) was investigated. Using a new composite electrode fabricated with carbon nanotubes and ionic liquids (CNTs-ILE), continuous dynamic amperometric detection of the enzymatic reaction was achieved. The results indicated that the cyclic voltammetry characteristics of the CNTs-ILE were better than those of glassy carbon electrode, and the CNTs-ILE had good anti-fouling property when detected PNP. When the concentration range of AP was 1×10-3 U/mL to 1×10-1 U/mL, the current had a good proportional relationship with the concentration of AP. This method could be used to detect AP fast. CNTs-ILE's good anti-fouling and low material cost, simply prepared, easily update surface properties made this electrode expect to have a further development in electrochemical detection.Then, the process of detecting Cry lAb protein using electrochemical immunosensors was introduced, and results were compared with the optical method. When using Electrochemical method to detect the final product, the peak current had positive correlation with the concentration of antigen, meanwhile, compared with SWV, DPV had relatively advantage; on the other hand, compared with the optical method, under same color time, the OD405 was only 0.1688 when concentration of antigen was 10 ppb, while with the electrochemical method, there were obvious peaks when the concentration of antigen was only 0.5 ppb. So the electrochemical method was more sensitive than optical methods.Finally, the process of detecting Cry 1Ab protein using electrochemical immunosensors based on magnetic beads was introduced, and results were compared with the electrochemical method did not use magnetic beads. It was found that bead-based electrochemical method had no obvious advantage compared with method did not use magnetic beads. This subject analyzed the reasons as follows:the dispersion of carboxyl-beads made from ourselves was bad and they would join together easily; the activity of antigen and antibody is not very ideal; there maybe some mistakes during the operation of experimental, these three reasons provided some references to future researchers.