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This work illustrates the potentiality of a mixed array merging the Nanowire and thin film metal oxide technologies to develop an electronic nose as a tool to monitor the human skin and food pathogen microbiota. Nanowire and thin film sensors have been fabricated, characterized and then integrated together to develop a hybrid device that can enhance the sensing performance. Different blends of microorganisms grown in artificial sweat have been tested. Classical techniques, like GC–MS (Gas Chromatography–Mass Spectrometry) with SPME (Solid Phase Micro Extraction) have been employed in parallel, in order to have a multidisciplinary approach and a consistent data set. The obtained results show the potentiality of the proposed electronic nose to discriminate between the different blends of microorganisms and to follow up microbiota growth inside the blends. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bacterial cellulose as organic substrate for a new generation of MOX sensors. • ZnO integration on bacterial cellulose as semiconductor sensing material. • MOS semiconductor organic sensor prototype assembly. • Room temperature sensor activation through the UV light and measurement. • Room temperature measurements. • Good response to gas test as NO 2 , Acetone, Ethanol and H 2. Abstract Recently a high interest has grown around the use of organic materials, as cellulose, in engineering and electronic fields due to the possibility to create hybrid devices. The objective of this work was to create a new generation of biocompatible bacterial cellulose Metal Oxides (MOX) gas sensors. ZnO semiconductor sensing material was used due to its well-known functional performances and the UV light activation possibility at room temperature. Bacterial cellulose membranes have been produced, active ZnO layer was deposited and the final sensing device was assembled and tested in presence of different chemical compounds. The prototypes showed good response to nitrogen dioxide, acetone and ethanol at room temperature, demonstrating the possibility to use bacterial cellulose as eco and environmental friendly composite transducers material for, but not limited to, chemical sensors. [ABSTRACT FROM AUTHOR]

Tea is the second most consumed beverage, and its aroma, determined by volatile compounds (VOCs) present in leaves or developed during the processing stages, has a great influence on the final quality. The goal of this study is to determine the volatilome of different types of tea to provide a competitive tool in terms of time and costs to recognize and enhance the quality of the product in the food chain. Analyzed samples are representative of the three major types of tea: black, green, and white. VOCs were studied in parallel with different technologies and methods: gas chromatography coupled with mass spectrometer and solid phase microextraction (SPME-GC-MS) and a device called small sensor system, (S3). S3 is made up of tailor-made metal oxide gas sensors, whose operating principle is based on the variation of sensor resistance based on volatiloma exposure. The data obtained were processed through multivariate statistics, showing the full file of the pre-established aim. From the results obtained, it is understood how supportive an innovative technology can be, remotely controllable supported by machine learning (IoF), aimed in the future at increasing food safety along the entire production chain, as an early warning system for possible microbiological or chemical contamination. [ABSTRACT FROM AUTHOR]

In this paper, we present the investigations on metal oxide-based gas sensors considering the works performed at SENSOR lab, University of Brescia (Italy). We reported the developments in synthesis techniques for the preparation of doped and functionalized low-dimensional metal oxide materials. Furthermore, we discussed our achievements in the fabrication of heterostructures with unique functional features. In particular, we focused on the strategies to improve the sensing performance of metal oxides at relatively low operating temperatures. We presented our studies on surface photoactivation of sensing structures considering the application of biocompatible materials in the architecture of the functional devices as well. [ABSTRACT FROM AUTHOR]