Disposable electrochemical biosensors in microbiology

The analytical objective of developing sensitive, selective and rapid methods for the analysis of different substances in complex matrices has led to the production of several chemical sensors. Among the analytical applications of chemical sensors, the one involving the early detection of pathogen microorganisms can be considered essential in fields such as, • Food industry • Clinical and environmental analysis for avoidance of human health problems • Animals and plants epidemics [1-3]. In this respect, chemical sensors can be considered as an alternative to the traditional analytical instrumentation in rapid and sensitive analysis of these species. A chemical sensor is a device that responds to a particular analyte in a selective way through a chemical reaction. They can be used for the qualitative or quantitative determination of the analyte [4]. There are two basic components in a chemical sensor: a recognition system called receptor and, the transducer. The receptor is the sensitive part of the sensor and it also confers the selectivity needed for a suitable analyte determination without other species interference. Thus, the receptor recognizes the chemical information present in the sample. This information is then changed into a signal in order to be recognized by the transducer. The latter finally carries out the conversion of the signal into an observable response. Biosensors can be considered as a type of chemical sensors with high sensitivity and applicability levels. Following the IUPAC definition [5], a biosensor is an integrated receptor-transducer device, which is capable of providing selective quantitative or semi-quantitative analytical information using a biological recognition element (Fig. 1).