Functionalization of screen-printed gold electrodes for the development of electrochemical biosensors

Identifier:  TFG:1631

Handle: https://hdl.handle.net/20.500.11797/TFG1631

Authors:  Pérez Mora, David

Abstract:
Myotonic muscular dystrophy is a disease that causes progressive muscle weakness and difficulty in relaxing the muscles after they have been contracted. The patients affected have abnormally high levels of IL-6 and TNF-α. The detection of these cytokines could be a breakthrough for the development of preventive treatments for the patients. The aim of this project is the development of an electrochemical immunosensing system for the detection of these cytokines in skeletal muscles samples. The optimization steps for the development of this immunosensor, which is based on the use of screen-printed gold electrodes, are described. The principle of it is the high affinity that these immunoglobulins have for their corresponding antigen. The construction of the immunoassay consists of a self-assembled monolayer or SAM, the immobilization of the antibody after a previous activation step, the recognition of the analyte or antigen to be detected, the addition of a second biotinylated anti-antigen antibody and, finally, the addition of the streptavidin-horseradish peroxidase (SAv-HRP) bioconjugate. The peroxidase produces the signal, due to the addition of the corresponding substrate. Various experimental designs were developed with the aim of optimizing the different parameters of the immunoassay construction, in addition to the pretreatment of the electrodes and the blocking after the immobilization of the antibody, in order to eliminate possible non-specific interactions. The best method to pretreat the gold electrodes was the UV/O3 cleaner during 15 minutes. In reference to the immunoassay construction, the best configuration of the SAM and the blocking was by 5 mM DTSSP and BSA 1 %, respectively. On the other hand, the results showed that the non-specific interactions were mainly produced by the biotinylated antibody with a small contribution from the Sav-HRP bioconjugate.