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12 pages, 2875 KiB

Open AccessArticle

Development of Tin Oxide-Based Nanosensors for Electronic Nose Environmental Applications

by Isabel Sayago, Manuel Aleixandre and José Pedro Santos

Biosensors 2019, 9(1), 21; https://doi.org/10.3390/bios9010021 - 05 Feb 2019

Cited by 25 | Viewed by 6207

Tin oxide nanofibres (NFs) are used as nanosensors in electronic noses. Their performance is compared to that of oxide commercial chemical sensors for pollutant detection. NFs were grown by electrospinning and deposited onto silicon substrates with integrated micro-hotplates. NF morphology was characterized by [...] Read more.

Tin oxide nanofibres (NFs) are used as nanosensors in electronic noses. Their performance is compared to that of oxide commercial chemical sensors for pollutant detection. NFs were grown by electrospinning and deposited onto silicon substrates with integrated micro-hotplates. NF morphology was characterized by scanning electron microscopy (SEM). The NFs presented high sensitivity to NO₂ at low temperature. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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11 pages, 1439 KiB

Open AccessArticle

Innovative Sensor Approach to Follow Campylobacter jejuni Development

by Estefanía Núñez-Carmona, Marco Abbatangelo and Veronica Sberveglieri

Biosensors 2019, 9(1), 8; https://doi.org/10.3390/bios9010008 - 07 Jan 2019

Cited by 20 | Viewed by 5564

Abstract

Campylobacter spp infection affects more than 200,000 people every year in Europe and in the last four years a trend shows an increase in campylobacteriosis. The main vehicle for transmission of the bacterium is contaminated food like meat, milk, fruit and vegetables. In [...] Read more.

Campylobacter spp infection affects more than 200,000 people every year in Europe and in the last four years a trend shows an increase in campylobacteriosis. The main vehicle for transmission of the bacterium is contaminated food like meat, milk, fruit and vegetables. In this study, the aim was to find characteristic volatile organic compounds (VOCs) of C. jejuni in order to detect its presence with an array of metal oxide (MOX) gas sensors. Using a starting concentration of 10³ CFU/mL, VOCs were analyzed using Gas-Chromatography Mass-Spectrometry (GC-MS) with a Solid-Phase Micro Extraction (SPME) technique at the initial time (T0) and after 20 h (T20). It has been found that a Campylobacter sample at T20 is characterized by a higher number of alcohol compounds that the one at T0 and this is due to sugar fermentation. Sensor results showed the ability of the system to follow bacteria curve growth from T0 to T20 using Principal Component Analysis (PCA). In particular, this results in a decrease of ΔR/R₀ value over time. For this reason, MOX sensors are a promising technology for the development of a rapid and sensitive system for C. jejuni. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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13 pages, 3550 KiB

Open AccessArticle

ZIF Nanocrystal-Based Surface Acoustic Wave (SAW) Electronic Nose to Detect Diabetes in Human Breath

by Fabio A. Bahos, Arianee Sainz-Vidal, Celia Sánchez-Pérez, José M. Saniger, Isabel Gràcia, María M. Saniger-Alba and Daniel Matatagui

Biosensors 2019, 9(1), 4; https://doi.org/10.3390/bios9010004 - 26 Dec 2018

Cited by 31 | Viewed by 9431

Abstract

In the present work, a novel, portable and innovative eNose composed of a surface acoustic wave (SAW) sensor array based on zeolitic imidazolate frameworks, ZIF-8 and ZIF-67 nanocrystals (pure and combined with gold nanoparticles), as sensitive layers has been tested as a non-invasive [...] Read more.

In the present work, a novel, portable and innovative eNose composed of a surface acoustic wave (SAW) sensor array based on zeolitic imidazolate frameworks, ZIF-8 and ZIF-67 nanocrystals (pure and combined with gold nanoparticles), as sensitive layers has been tested as a non-invasive system to detect different disease markers, such as acetone, ethanol and ammonia, related to the diagnosis and control of diabetes mellitus through exhaled breath. The sensors have been prepared by spin coating, achieving continuous sensitive layers at the surface of the SAW device. Low concentrations (5 ppm, 10 ppm and 25 ppm) of the marker analytes were measured, obtaining high sensitivities, good reproducibility, short time response and fast signal recovery. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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13 pages, 6124 KiB

Open AccessArticle

Non-Invasive Diagnosis of Diabetes by Volatile Organic Compounds in Urine Using FAIMS and Fox4000 Electronic Nose

by Siavash Esfahani, Alfian Wicaksono, Ella Mozdiak, Ramesh P. Arasaradnam and James A. Covington

Biosensors 2018, 8(4), 121; https://doi.org/10.3390/bios8040121 - 01 Dec 2018

Cited by 38 | Viewed by 7061

Abstract

The electronic nose (eNose) is an instrument designed to mimic the human olfactory system. Usage of eNose in medical applications is more popular than ever, due to its low costs and non-invasive nature. The eNose sniffs the gases and vapours that emanate from [...] Read more.

The electronic nose (eNose) is an instrument designed to mimic the human olfactory system. Usage of eNose in medical applications is more popular than ever, due to its low costs and non-invasive nature. The eNose sniffs the gases and vapours that emanate from human waste (urine, breath, and stool) for the diagnosis of variety of diseases. Diabetes mellitus type 2 (DM2) affects 8.3% of adults in the world, with 43% being underdiagnosed, resulting in 4.9 million deaths per year. In this study, we investigated the potential of urinary volatile organic compounds (VOCs) as novel non-invasive diagnostic biomarker for diabetes. In addition, we investigated the influence of sample age on the diagnostic accuracy of urinary VOCs. We analysed 140 urine samples (73 DM2, 67 healthy) with Field-Asymmetric Ion Mobility Spectrometry (FAIMS); a type of eNose; and FOX 4000 (AlphaM.O.S, Toulouse, France). Urine samples were collected at UHCW NHS Trust clinics over 4 years and stored at −80 °C within two hours of collection. Four different classifiers were used for classification, specifically Sparse Logistic Regression, Random Forest, Gaussian Process, and Support Vector on both FAIMS and FOX4000. Both eNoses showed their capability of diagnosing DM2 from controls and the effect of sample age on the discrimination. FAIMS samples were analysed for all samples aged 0–4 years (AUC: 88%, sensitivity: 87%, specificity: 82%) and then sub group samples aged less than a year (AUC (Area Under the Curve): 94%, Sensitivity: 92%, specificity: 100%). FOX4000 samples were analysed for all samples aged 0–4 years (AUC: 85%, sensitivity: 77%, specificity: 85%) and a sub group samples aged less than 18 months: (AUC: 94%, sensitivity: 90%, specificity: 89%). We demonstrated that FAIMS and FOX 4000 eNoses can discriminate DM2 from controls using urinary VOCs. In addition, we showed that urine sample age affects discriminative accuracy. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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11 pages, 3828 KiB

Open AccessArticle

Cerium Oxide-Tungsten Oxide Core-Shell Nanowire-Based Microsensors Sensitive to Acetone

by Milena Tomić, Milena Šetka, Ondřej Chmela, Isabel Gràcia, Eduard Figueras, Carles Cané and Stella Vallejos

Biosensors 2018, 8(4), 116; https://doi.org/10.3390/bios8040116 - 23 Nov 2018

Cited by 14 | Viewed by 5634

Abstract

Gas sensitive cerium oxide-tungsten oxide core-shell nanowires are synthesized and integrated directly into micromachined platforms via aerosol assisted chemical vapor deposition. Tests to various volatile organic compounds (acetone, ethanol, and toluene) involved in early disease diagnosis demonstrate enhanced sensitivity to acetone for the [...] Read more.

Gas sensitive cerium oxide-tungsten oxide core-shell nanowires are synthesized and integrated directly into micromachined platforms via aerosol assisted chemical vapor deposition. Tests to various volatile organic compounds (acetone, ethanol, and toluene) involved in early disease diagnosis demonstrate enhanced sensitivity to acetone for the core-shell structures in contrast to the non-modified materials (i.e., only tungsten oxide or cerium oxide). This is attributed to the high density of oxygen vacancy defects at the shell, as well as the formation of heterojunctions at the core-shell interface, which provide the modified nanowires with ‘extra’ chemical and electronic sensitization as compared to the non-modified materials. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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Review

Jump to: Research

19 pages, 918 KiB

Open AccessReview

Evolution of Electronic Noses from Research Objects to Engineered Environmental Odour Monitoring Systems: A Review of Standardization Approaches

by Domenico Cipriano and Laura Capelli

Biosensors 2019, 9(2), 75; https://doi.org/10.3390/bios9020075 - 31 May 2019

Cited by 32 | Viewed by 7700

Abstract

Since electronic noses are used more and more for air quality monitoring purposes, and in some countries are starting to have a legal value, there is a need for standardization and programs for the quality verification of instruments. Such quality programs have the [...] Read more.

Since electronic noses are used more and more for air quality monitoring purposes, and in some countries are starting to have a legal value, there is a need for standardization and programs for the quality verification of instruments. Such quality programs have the aim to guarantee the main characteristics of the instrument for both the final user and local authorities, let the user establish a suitable maintenance procedure and give information on measurement uncertainty. One critical aspect when dealing with electronic noses for environmental odour monitoring is that environmental odours are complex mixtures that are not repeatable nor reproducible, giving that they are not suitable for quality verifications. This paper aims to review and discuss the different approaches that can be adopted in order to perform quality checks on electronic noses (e-noses) used for environmental odour monitoring, thereby referring to existing technical standards, such as the Dutch NTA 9055:2012, the new German VDI 3518-3:2018, and the Italian UNI 1605848 project, which directly refer to electronic noses. Moreover, also the European technical standards that are prescriptive for automatic measuring systems (AMSs) are taken into consideration (i.e., EN 14181:2014 and EN 15267:2009), and their possible applicability to electronic noses is investigated. Finally, the pros and cons of the different approaches are presented and discussed in the conclusions section. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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20 pages, 572 KiB

Open AccessReview

Use of Electronic Noses for Diagnosis of Digestive and Respiratory Diseases through the Breath

by Carlos Sánchez, J. Pedro Santos and Jesús Lozano

Biosensors 2019, 9(1), 35; https://doi.org/10.3390/bios9010035 - 28 Feb 2019

Cited by 60 | Viewed by 11103

Abstract

The increased occurrence of chronic diseases related to lifestyle or environmental conditions may have a detrimental effect on long-term health if not diagnosed and controlled in time. For this reason, it is important to develop new noninvasive early diagnosis equipment that allows improvement [...] Read more.

The increased occurrence of chronic diseases related to lifestyle or environmental conditions may have a detrimental effect on long-term health if not diagnosed and controlled in time. For this reason, it is important to develop new noninvasive early diagnosis equipment that allows improvement of the current diagnostic methods. This, in turn, has led to an exponential development of technology applied to the medical sector, such as the electronic nose. In addition, the appearance of this type of technology has allowed the possibility of studying diseases from another point of view, such as through breath analysis. This paper presents a bibliographic review of past and recent studies, selecting those investigations in which a patient population was studied with electronic nose technology, in order to identify potential applications of this technology in the detection of respiratory and digestive diseases through the analysis of volatile organic compounds present in the breath. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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8 pages, 572 KiB

Open AccessReview

Use of Electronic Noses in Seawater Quality Monitoring: A Systematic Review

by Alessandro Tonacci, Francesco Sansone, Raffaele Conte and Claudio Domenici

Biosensors 2018, 8(4), 115; https://doi.org/10.3390/bios8040115 - 23 Nov 2018

Cited by 10 | Viewed by 4486

Abstract

Electronic nose (eNose) systems are particularly appreciated for their portability, usability, relative low cost, and real-time or near real-time response. Their application finds space in several domains, including environmental monitoring. Within this field, marine monitoring is of particular scientific relevance due to the [...] Read more.

Electronic nose (eNose) systems are particularly appreciated for their portability, usability, relative low cost, and real-time or near real-time response. Their application finds space in several domains, including environmental monitoring. Within this field, marine monitoring is of particular scientific relevance due to the fragility of this specific environment, daily threatened by human activities that can potentially bring to catastrophic and irreversible consequences on marine wildlife. Under such considerations, a systematic review, complying with the PRISMA guidelines, was conducted covering the period up to 15 October 2018, in PubMed, ScienceDirect, and Google Scholar. Despite the relatively low number of articles published on this specific topic and the heterogeneity of the technological approaches employed, the results obtained by the various groups highlight the positive contribution eNose has given and can provide in near future for the monitoring and safeguarding of this delicate environment. Full article

(This article belongs to the Special Issue Electronic Noses for Biomedical Applications and Environmental Monitoring)

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