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The investigations on artificial olfactory systems in the last 20 years were basically concerned with the development of chemical sensors with selectivity properties similar to that of natural receptor. As a consequence, among the various features of olfaction emerged in the last two decades only the presumed non-selectivity of receptors is currently considered. Therefore, as physiology progresses enlighted the mechanisms of elaboration of signals in the olfactory pathways, artificial nose concept did not evolve much since its first conjecture. In this paper, an attempt to introduce artificial noses more adherent to recent views on olfaction is presented. The typical methodology of translation of conventional analog sensor signals into biologically similar spikes is applied to chemical sensors and a demonstration of the preservation of information sufficient for odour classification is given through a practical example.

Electronic noses are arrays of partially selective chemical sensors. These systems appeared at the end of the eighties as technological attempts to mimic some of the functions of natural olfaction. Although they were introduced as a sort of olfaction model they were soon applied to the qualitative analysis in a number of different fields disciplines such as food analysis, environmental control and industrial processes. Among these fields also medicine was considered, in particular taking into account the diagnostic role that olfaction plays in many traditional medicines. In this paper the use of electronic noses in medicine is discussed with a particular emphasis on the possible use of this technology in telemedicine.

An increase in produced hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase together with water, thus one of the approaches of monitoring hydrogen peroxide in the EB is to condense it and then to perform the hydrogen peroxide measurement in the condensate. Earlier, a hydrogen peroxide sensor based on an Electrolyte Metal Oxide Semiconductor Field-Effect Transistor, EMOSFET, has been investigated. The sensor shows the possibility to measure hydrogen peroxide at a concentration of micro-molar level. Due to its miniaturizability, the sensor is able to detect hydrogen peroxide in a small solution volume, especially suitable for monitoring of hydrogen peroxide in the EB. In this paper, a new setup for condensation hydrogen peroxide in the EB is introduced. The setup consists of a cooling part using a Peltier cooler for condensation of the exhaled breath air and the EMOSFET based hydrogen peroxide sensor. Preliminary results on the collection and measurement of hydrogen peroxide in artificial EB are given.

Transport properties of a field effect transistor based on pentacene have been investigated by experimental and numerical analysis. Moreover, thin film transistors based on porphyrin have been realized and characterized. In order to derive from basic principles the transport properties of the organic semiconductors, we used a Monte Carlo (MC) simulator to calculate the field-dependent mobility. The overall device simulation is performed by using two-dimensional drift-diffusion simulations taking into account field-dependent mobility obtained from MC simulations, interface/bulk trap states and fixed charge density at the organic/oxide interface. We demonstrate how carrier mobility can be extracted from experimental device characteristics, without using the conventional MOSFET theory that could lead to the wrong result. Finally we demonstrate the realization of simple organic logic circuitry, namely an organic inverter with a different configuration of load transistor.

The development of artificial taste systems although devised since two decades has been hampered by the difficulties to find a material easily modifiable to form arrays of non-selective sensors endowed with sufficient cross-selectivities. On the other hand, materials with such features have been extensively studied for artificial olfaction systems. In particular, metalloporphyrins revealed interesting properties making them suitable for electronic nose development. In this paper, an investigation of the properties of glassy carbon electrodes modified with electropolymerised porphyrins is carried out. In particular, the study of the porphyrin structure to sensitivity relationship has been approached. Results confirm the behaviour observed with porphyrin-based gas sensors, namely the important role played by the metal atom in determining the sensor performances. An array of five glassy carbon modified electrodes was tested in a sample experiment aimed at discriminating among five compounds each belonging to a different basic taste class. Results shows that the taste discrimination is positively carried out for concentrations down to 10(-6) M. Obtained results are a reasonable basis to devise the development of artificial taste systems for a wide range of practical applications.

In this paper a sensor phase space is introduced and the analysis of trajectories in this space is proposed as a method to evaluate the sensor response. The phase space gives the opportunity to introduce a novel feature describing the area spanned by the trajectory during adsorption and/or desorption of chemicals from the sensor. A comparison with the usual features resulted in a better accuracy and a shortest measurement time.