Application of Electrochemical Methods in Biosensing Technologies

Introducing biochemical factor to electronic devices have created a new branch of science. Recent development in biosensing technology enabled progress in pathogens detection. Currently, wide range of biomarkers (enzymes, peptides, DNA, microorganisms, etc. )recognize various target analytes, starting from basic metabolism changes to serious infections caused by pathogens. Improved sensitivity, selectivity and response time of sensors have instantly replaced traditional techniques. Easy handling, low production costs and miniaturization have met therapeutics need. Biosensing technologies are very strong point in telemedicine in public healthcare. This chapter will focus on electrochemical techniques for pathogens detection and show trending applications in biosensing technologies

Methods for increasing the sensing performance of metal oxide semiconductor gas sensors at ppb concentration levels

Metal oxide semiconductor gas sensors are in general well suited for high volume gas sensing applications, e.g. air quality monitoring, due to their low cost and high sensitivity. However, in many applications, the gases to be detected can occur in very low concentrations, which complicates selective measurement of specific components. In this thesis, several methods are presented which improve the performance of such sensors for the detection of gases at trace concentrations. First, the design and characterization of a gas mixing system is described, which allows generation of test gases in the ppb (parts per billion) concentration range. Several well established techniques are then tested for their applicability at these low concentration levels. Key elements are cyclic modulation of the sensor temperature and signal processing based on methods for pattern recognition, for both single sensors and combined sensor signals. A novel development is an integrated micro system in which gas pre-concentration is realized in combination with the sensor. In addition to the technical developments, the reproducibility of the results has been investigated in an inter-laboratory comparison, where a measurement system for benzene has been characterized in two different setups for test gas generation. The presented methods provide a basis for using low-cost metal oxide semiconductor gas sensors for potential applications in the field of trace gas analysis.Metalloxid-Halbleiter-Gassensoren (MOS) sind aufgrund ihrer hohen Sensitivität und geringen Preises grundsätzlich gut geeignet für Gasdetektion in Anwendungen mit hohen Stückzahlen, zum Beispiel für die Überwachung von Luftqualität. In diesen können die zu detektierenden Gase jedoch in sehr niedrigen Konzentrationen auftreten, was eine gezielte Messung einzelner Komponenten erschwert. In dieser Arbeit werden Verfahren vorgestellt, mit denen die Leistung solcher Sensoren für die Detektion von Gasen in Spuren-Konzentrationen verbessert wird. Zunächst werden das Design und die Charakterisierung einer Gasmischanlage beschrieben, die eine zuverlässige Generierung von Testgasen im ppb-Bereich (parts per billion) ermöglicht. Mehrere etablierte Verfahren werden dann auf ihre Eignung für diesen niedrigen Konzentrationsbereich getestet. Zentrale Elemente sind hierbei eine zyklische Änderung der Sensortemperatur und Signalverarbeitung basierend auf Methoden zu Mustererkennung, sowohl für einzelne Sensoren als auch für kombinierte Signale. Eine neue Entwicklung ist ein integriertes Mikrosystem, in dem zusätzlich zum Sensor eine Gas-Aufkonzentration realisiert ist. Neben den technischen Entwicklungen wurde die Reproduzierbarkeit der Ergebnisse in einer Vergleichsmessung in zwei Labors untersucht; hier wurde ein Messsystem für Benzol in zwei unterschiedlichen Setups zur Gasaufgabe getestet. Die vorgestellten Methoden bieten eine Grundlage zum Einsatz der günstigen MOS-Gassensoren für Anwendungen im Bereich von Spurengasen

Novel Isoprene Sensor for a Flu Virus Breath Monitor

A common feature of the inflammatory response in patients who have actually contracted influenza is the generation of a number of volatile products of the alveolar and airway epithelium. These products include a number of volatile organic compounds (VOCs) and nitric oxide (NO). These may be used as biomarkers to detect the disease. A portable 3-sensor array microsystem-based tool that can potentially detect flu infection biomarkers is described here. Whether used in connection with in-vitro cell culture studies or as a single exhale breathalyzer, this device may be used to provide a rapid and non-invasive screening method for flu and other virus-based epidemics

Novel Isoprene Sensor for a Flu Virus Breath Monitor

A common feature of the inflammatory response in patients who have actually contracted influenza is the generation of a number of volatile products of the alveolar and airway epithelium. These products include a number of volatile organic compounds (VOCs) and nitric oxide (NO). These may be used as biomarkers to detect the disease. A portable 3-sensor array microsystem-based tool that can potentially detect flu infection biomarkers is described here. Whether used in connection with in-vitro cell culture studies or as a single exhale breathalyzer, this device may be used to provide a rapid and non-invasive screening method for flu and other virus-based epidemics