| 1. |
- Andersson, Mike, et al.
(författare)
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Development of a ChemFET sensor with molecular films of porphyrins as sensitive layer
- 2001
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Ingår i: Sensors and actuators. B, Chemical. - 0925-4005 .- 1873-3077. ; 77:1-2, s. 567-571
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of chemical species with molecular films of porphyrins causes variations of the work function of the film itself, as it has been recently demonstrated by using the Kelvin probe technique. This characteristic makes porphyrins films suitable to be used as sensitive layers in ChemFET sensors. In this paper, we present a preliminary report about the fabrication and testing of such gas sensitive devices. The technological solutions towards an optimised device are also illustrated and discussed. © 2001 Elsevier Science B.V.
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| 2. |
- Cao, Z., et al.
(författare)
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Porphyrin electropolymers as opto-electrochemical probe for the detection of red-ox analytes
- 2014
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Ingår i: Sensors: Proceedings of the First National Conference on Sensors, Rome 15-17 February, 2012. - New York, NY : Springer Science Business Media. - 9781461438595 ; , s. 49-55
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Konferensbidrag (refereegranskat)abstract
- The application of pyrrole-substituted porphyrin electropolymers for simultaneous optical and electrochemical analysis of red-ox active analytes, namely diazo-conjugated dyes of Sudan family, is presented. Sudan colorants are widely used in many fields, but accurate screening of their consumption is required due to their high toxicity. The inherent electrochemical activity of Sudan dyes, as far as their intense coloration, makes possible to find the appropriate conditions of hybrid optical and electrochemical porphyrin electropolymer based sensor array system application. This approach allowed a significant increase in the chemical information, improving the analytical system performance in terms of selectivity and sensitivity, and permitted the fast and simple monitoring of Sudan dye analytes.
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| 3. |
- Di, Natale C., et al.
(författare)
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An experimental biomimetic platform for artificial olfaction
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:9
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Tidskriftsartikel (refereegranskat)abstract
- Artificial olfactory systems have been studied for the last two decades mainly from the point of view of the features of olfactory neuron receptor fields. Other fundamental olfaction properties have only been episodically considered in artificial systems. As a result, current artificial olfactory systems are mostly intended as instruments and are of poor benefit for biologists who may need tools to model and test olfactory models. Herewith, we show how a simple experimental approach can be used to account for several phenomena observed in olfaction. An artificial epithelium is formed as a disordered distributed layer of broadly selective color indicators dispersed in a transparent polymer layer. The whole epithelium is probed with colored light, imaged with a digital camera and the olfactory response upon exposure to an odor is the change of the multispectral image. The pixels are treated as olfactory receptor neurons, whose optical properties are used to build a convergence classifier into a number of mathematically defined artificial glomeruli. A non-homogenous exposure of the test structure to the odours gives rise to a time and spatial dependence of the response of the different glomeruli strikingly similar to patterns observed in the olfactory bulb. The model seems to mimick both the formation of glomeruli, the zonal nature of olfactory epithelium, and the spatio-temporal signal patterns at the glomeruli level. This platform is able to provide a readily available test vehicle for chemists developing optical indicators for chemical sensing purposes and for biologists to test models of olfactory system organization. © 2008 Di Natale et al.
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| 5. |
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| 6. |
- Di Natale, C, et al.
(författare)
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An artificial olfaction system based on the optical imaging of a large array of chemical reporters
- 2009
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - : Elsevier BV. - 0925-4005. ; 142:2, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- Electronic noses are object of research since more than two decades; nonetheless. the analogies between natural and olfaction systems are still limited to the selectivity properties of the receptors. The implementation of more sophisticated features such as the large number of receptors and the glomeruli layer have been hampered by technical difficulties related to the management of a large number of contemporaneous signals. As demonstrated in the past, optical imaging is a read-out technique for sensors development that can provide large sensor arrays. In this paper an artificial olfaction system based on the imaging of a continuous layer of chemical indicators is illustrated. The system incorporates an array of thousands of sensors, corresponding to the pixels of the image. The choice of Computer Screen Photoassisted Technology as a platform for optical interrogation of the sensing layer allows for the definition of a strategy for an automatic definition of a glomeruli layer based on the classification of the optical fingerprints of the image pixels. Chemical indicators were dissolved into a polymeric matrix providing the further property of odor diffusion mimicking the functions of the olfactory mucosa. The system has been tested in a simple experiment and data have been treated applying a lateral inhibition to the glomeruli layer resulting in a dynamic pattern resembling that observed in natural olfaction.
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| 7. |
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| 8. |
- Filippini, Daniel, 1968-, et al.
(författare)
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Computer screen photo-assisted techniques for global monitoring of environmental and sanitary parameters
- 2007
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 121:1, s. 93-102
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Tidskriftsartikel (refereegranskat)abstract
- The computer screen photo-assisted technique (CSPT) is a measuring method that uses regular computer screens as controlled light sources and web cameras as imaging detectors for optical evaluations of sensing substances, which optical properties respond to target analytes. The fact, that CSPT uses a globally distributed and familiar infrastructure as instrumentation and that is able to serve multiple targets with the same setup, makes it an attractive candidate for home testing. This article reviews the CSPT concept and focuses in two recent studies that demonstrate thorough CSPT determinations using a handy and eventually disposable assay format, with the potential to be as ubiquitous as the CSPT platforms themselves. The implications of such combination of technologies is discussed, and its potential to support the global monitoring of environmental and sanitary parameters, using Internet geography browsers, is analyzed. © 2006 Elsevier B.V. All rights reserved.
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| 11. |
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| 12. |
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| 13. |
- Filippini, Daniel, 1968-, et al.
(författare)
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Sorting of apricots with computer screen photoassisted spectral reflectance analysis and electronic nose
- 2006
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 119:1, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- Optical properties and aroma have been indicated as sources of information for the analysis of quality of fruits. Optical properties can be measured with several experimental arrangements and equipments that are often complex with result difficult to interpret. In recent years, a number of suggestions arose in the sensor community proposing the use of conventional computer peripheral devices as analytical instruments. Among them the combination of a computer screen and a webcam was demonstrated to be suitable to measure optical properties of materials. In this paper this arrangement is utilized to characterize the reflectance of apricot fruits that underwent different post-harvest treatment and mechanical damages. Optical measurements were complemented by aroma analysis with an electronic nose. The response of fruits to treatments was also monitored measuring CO2 (indicator of respiration) and ethylene (indicator of ripening), both these parameters are known to be influenced by post-harvest treatment and mechanical damages. Results show that a computer screen-webcam combination and an electronic nose are both sensitive to mechanical damages of fruits devising their use, after due optimization, for routine fruit sorting. © 2005.
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| 14. |
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| 15. |
- Gatto, E., et al.
(författare)
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Polychromatic fingerprinting of excitation emission matrices
- 2008
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 14:20, s. 6057-6060
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Tidskriftsartikel (refereegranskat)abstract
- The ability of a ubiquitous polychromatic excitation to support the fingerprinting of the Excitation Emission Matrices (EEM) of fluorescent indicators was reported. Solutions of fluorescent molecules, with concentration of 2µM for the absorption and 10µM for the emission measurements were prepared. Spectroscopic grade THF and distilled water passed through Milli-Q purification system were used as solvents. EEM measurements were carried out on a spectrofluorimeter, operating in the 390-700 nm detection range, with excitations at 20 nm intervals within the same range. During the measurement, the screen displayed a sequence of 50 colors and for every color, the transmission and emission spectrum of both the reference and the sample were recorded. Illuminating colors in the red region are not able to excite fluorescence and this can be seen in the spectra for red light.
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| 16. |
- Guanais Branchini, C., et al.
(författare)
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Detection of toxic compounds in water with an array of optical reporters
- 2015
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Ingår i: EUROSENSORS 2015. - : ELSEVIER SCIENCE BV. ; , s. 146-149
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Konferensbidrag (refereegranskat)abstract
- An opto-electronic tongue, prepared using porphyrins, pH indicators, and their mixtures, has been tested for the analysis of toxic compounds in potable water. The color changes of sensitive dyes immersed in a water solution containing the target analytes were measured with an optical platform made by four LEDs (as light sources) and a digital camera (detector). We demonstrate that blends of dyes might be endowed with sensing properties wider than those of the single constituents, enabling the identification of a range of toxic compounds at concentrations smaller than 10(-6) mol/L. Furthermore, the use of the reporters in a sensor array configuration allows for the identification of the compounds disregarding their concentration. (C) Published by Elsevier Ltd.
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| 17. |
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| 18. |
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| 19. |
- Martinelle, E, et al.
(författare)
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FET Transduction of Electric Dipole Changes in Organic Layers
- 2007
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Ingår i: TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference. - : IEEE. - 1424408423 - 1424408415 ; , s. 1895-1898
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Konferensbidrag (refereegranskat)abstract
- Modern chemistry makes possibile the production of artificial receptors endowed with interaction sites specific towards selected analytes. To fabricate chemical sensors a transducer able to preserve the selectivity of such sensing layers is requested. We demonstrate the Field Effect Transistors (FET) coated by metalloporphyrins emphasizes the coordination of analytes with the sensing molecules with respect to the weakest forces that tend to cancel the selectivity. Molecular simulations show that coordination of gases such as carbon monoxide and nitric oxide greatly change the porphyrin electric dipole both in magnitude and direction inducing a large FET signal shift.
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| 20. |
- Martinelli, E, et al.
(författare)
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Odor Processing with an experimental model of Olfactory epithelium and bulb
- 2011
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Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 36:1, s. E4-E4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Artificial olfaction was introduced as a model tool to investigateolfaction properties [1]. Nonetheless, the only analogy between the natural and the artificial system lies just in the selectivity proper- ties of the receptors. The implementation of more sophisticated fea- tures such as the large number of receptors and the glomerular layer have been hampered by technical difficulties related to the manage- ment of large numbers of simultaneous signals.As demonstrated in the past, optical imaging is a read-out tech- nique for sensors development that can provide large sensor arrays [2]. On that basis, we recently introduced an artificial olfaction sys- tem based on the imaging of a continuous layer of chemical indi- cators [3]. In this situation an image sensor provides a segmentation of the whole sensing layer in a number of elementary units corre- sponding to the pixels of the image. Eventually, since it is possible to evaluate the optical properties of every single pixel, each pixel of the image may correspond to an individual sensor. In this regard, even low-resolution images may easily result in thousands of independ- ent sensing units.In our system a collection of arbitrarily shaped regions of color indicators is illuminated by a controlled light source; the optical characteristics of each pixel of the image are measured by a camera yielding the light intensities in the three channels red, green, and blue. The combination of illumination sequence and cameraread-out results in a fingerprint encoding the optical properties of the sensing layer portioned in image pixels. Even a simple clas- sification of these fingerprints assigns each pixel to a class, and each class contains pixels carrying the same color indicator. This behav- ior resembles the association between ORNs carrying the same chemical receptors into the same glomerulus [4]. On the basis of this analogy it is straightforward to describe the layer of indicators as an artificial epithelium, pixels of the image as artificial olfactory neu- rons, and the classes provided by the classifier as an abstract rep- resentation of artificial glomeruli.This system thus allows the generation of a complex model of olfaction, including glomerular compartmentalization [5], which is then applied to data generated by the exposure to pure and mixed gases. Results show that such a model enhances the discrimination of pure and mixed odors. Eventually, such a platform, apart from evidencing the similarities between natural and artificial olfactory systems, is also proposed as a practical tool to test olfactory models.1. K. Persaud and G. Dodds, Nature 299 (1982) 3522. Dickinson et al., Nature 382 (1996) 6973. C. Di Natale et al., PLoS ONE 3 (2008) 31394. P. Mombaerts, Annu Rev Neurosci 22 (1999) 4875. D. Schild and H. Riedel, Biophysical Journal, 61 (1992) 704
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| 21. |
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| 22. |
- Paolesse, R., et al.
(författare)
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Insights on the chemistry of a,c-biladienes from a CSPT investigation
- 2008
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 32:7, s. 1162-1166
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Tidskriftsartikel (refereegranskat)abstract
- Computer Screen Photoassisted Technique (CSPT) is a recent interesting approach for the development of optical sensor platforms using ubiquitous devices. We demonstrate here that the information obtained by CSPT measurements can be useful for other than sensing purposes and a computer set and a web camera can also be exploited as spectroscopic technique for the characterization of the compounds used as indicators. CSPT measurement data have been used to characterize novel features of the a,c-biladiene chemistry, which have been later confirmed by photophysical characterization carried out using classical instrumentation. The demonstrated analytical capabilities of a regular computer-web camera set reach a degree of complexity approaching that of fluorescence excitation-emission spectroscopy, something remarkable considering the exploitation of familiar and already well distributed devices. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
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| 23. |
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| 24. |
- Polese, D, et al.
(författare)
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Sharing data processing among replicated optical sensor arrays
- 2013
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 179:SI, s. 252-258
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Tidskriftsartikel (refereegranskat)abstract
- Sensor networks prompt a great deal of research interest within the computer and analytical sciences. To this regard, one of the most important issues is concerned with the interpretation of data that are collected by different sensors. Due to sensors non-reproducibility, this problem may also persist even when many replicas of the same sensors are considered. In this case additional calibrations may be required to use a common knowledge database. Noteworthy, the same problem arises in case of sensors replacement. In this paper we demonstrate that in case of optical chemical sensors drawing inspiration from the connectivity strategy of the olfactory bulb, this problem can find a straightforward solution when an image sensor is used to measure the optical properties of an extended sensing layer. If the sensing layer is formed by a number of spots of different indicators, it is demonstrated that a common data processing can be applied to any replica of the sensing layer even if the indicators are spotted with different geometries and in different quantities.
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