Development of biosensors for pathogen detection using microelectrode arrays

Resumen

Fast, reliable and low-cost methods for the screening of pathogens are paramount in areas such as environment, the food industry, healthcare and defense. The word pathogen defines any disease producing-agent but in this work, we will mainly focus on bacteria and at lower scale virus detection. With the constant progress of scientific knowledge, a fast diversification of the detection techniques is occuring, brought about by the appearance of imaginative new concepts within the scientific community. Biosensors are a perfect example of the combination of multidisciplinary knowledge. They encompass many fundamental, technological and scientific advances in biology, chemistry and physics. The work presented here describes different aspects leading to the elaboration of electrochemical biosensors, from the description of the sensors enabling the transduction of the signal to the recognition and detection of the target. An introduction is given which first describes biosensors, their place among the various existing detection techniques and the biological aspects that must be taken into account. Some background on the different electrochemical phenomena that will be found in this thesis is provided. The experimental part of this thesis first describes the efforts employed in defining a reliable immobilization procedure of antibodies on gold sensor surfaces, followed by their application in the detection of pathogen bacteria using electrochemical impedance spectroscopy. Another approach is then exposed which focuses on the amperometric detection of coliform bacteria and the HIV-virus through the screening of the enzymatic reaction of two different forms of ß-galactosidase.