Resumen de Interdigitated electrode arrays (idea) impedimetric transducers for bacterial biosensing applications
Biosensor technology, consisting of analytical devices that conjugate a bioreceptor with a transducer unit, has been applied in numerous research areas for the detection of different analytes of interest. Bacteria, especially pathogenic bacteria, are important targets to be sensed and identified in many fields, like clinical diagnosis, food industry or water safety, to prevent a great number of diseases in humans. However, bacteria can be employed in a wide range of beneficial applications, such as their use as biological indicators to determine the toxicity of various compounds.
In this thesis, the use of impedimetric transducers based on interdigitated electrode arrays (IDEA) has been proposed as a tool for the development of bacterial biosensing applications. Electrochemical Impedance Spectroscopy is a widely studied technique to characterize biosystems because it allows to monitor electrical events occurring on the surface of electrodes. This technique does not require additional markers for the transduction and can be used in a label-free operation mode and hence simplifying the biosensing assays. Among different types of impedimetric transducers interdigitated electrodes arrays are really advantageous in terms of easy-miniaturization, fast establishment of the steady-state signal response and increased signal-to-noise ratio. The utilization of IDEA devices as a base of a biosensor transducer permits reducing the time and cost per assay. In addition, the applicability of three-dimensional IDEA (3D-IDEA) is described and demonstrated, in which the electrode digits are separated by insulating barriers, to improve the sensitivity for the registration of superficial parameters compared with standard IDEA for bacteria sensing.
The main aim of this work is the elaboration and testing of robust and reproducible biosensing strategies using IDEA and 3D-IDEA impedance transducers with bacteria, as an analyte target or as a sensing element. In the first case, the detection of bacteria or bacterial endotoxins in liquid samples may be performed and, in the second one, novel microbial-based biosensors may be developed. To this end, IDEA devices have been (bio)functionalized using various grafting schemes for their use in four different applications.
