| 1. |
- Brebu, Mihai, et al.
(författare)
-
Putative volatile biomarkers of bovine tuberculosis infection in breath, skin and feces of cattle
- 2023
-
Ingår i: Molecular and Cellular Biochemistry. - : Springer. - 0300-8177 .- 1573-4919. ; 478:11, s. 2473-2480
-
Tidskriftsartikel (refereegranskat)abstract
- Bovine tuberculosis (bTB) is an infectious disease with significant impact on animal health, public health and international trade. Standard bTB screening in live cattle consists in injecting tuberculin and measuring the swelling at the place of injection few days later. This procedure is expensive, time-consuming, logistically challenging, and is not conclusive before performing confirmatory tests and additional analysis. The analysis of the volatile organic compounds (VOCs) emitted by non-invasive biological samples can provide an alternative diagnostic approach suitable for bTB screening. In the present study, we analyzed VOC samples emitted through the breath, feces and skin of 18 cows diagnosed with bTB from three farms from Romania, as well as of 27 negative cows for bTB from the same farms. Analytical studies employing gas chromatography coupled to mass spectrometry revealed 80 VOCs emitted through the breath, 200 VOCs released by feces, and 80 VOCs emitted through the skin. Statistical analysis of these compounds allowed the identification of 3 tentative breath VOC biomarkers (acetone; 4-methyldecane; D-limonene), 9 tentative feces VOC biomarkers (toluene; [(1,1-dimethylethyl)thio]acetic acid; alpha-thujene; camphene; phenol; o-cymene; 3-(1,1-dimethylethyl)-2,2,4,4-tetramethyl-3-pentanol; 2,5-dimethylhexane-2,5-dihydroperoxide; 2,4-di-tert-butylphenol), and 3 tentative skin VOC biomarkers (ammonia; 1-methoxy-2-propanol; toluene). The possible pathway of these volatile biomarkers is discussed.
|
|
| 2. |
- de Jesus Beleno-Saenz, Kelvin, et al.
(författare)
-
Non-Invasive Method to Detect Infection with Mycobacterium tuberculosis Complex in Wild Boar by Measurement of Volatile Organic Compounds Obtained from Feces with an Electronic Nose System
- 2021
-
Ingår i: Sensors. - : MDPI. - 1424-8220. ; 21:2
-
Tidskriftsartikel (refereegranskat)abstract
- More effective methods to detect bovine tuberculosis, caused by Mycobacterium bovis, in wildlife, is of paramount importance for preventing disease spread to other wild animals, livestock, and human beings. In this study, we analyzed the volatile organic compounds emitted by fecal samples collected from free-ranging wild boar captured in Donana National Park, Spain, with an electronic nose system based on organically-functionalized gold nanoparticles. The animals were separated by the age group for performing the analysis. Adult (>24 months) and sub-adult (12-24 months) animals were anesthetized before sample collection, whereas the juvenile (<12 months) animals were manually restrained while collecting the sample. Good accuracy was obtained for the adult and sub-adult classification models: 100% during the training phase and 88.9% during the testing phase for the adult animals, and 100% during both the training and testing phase for the sub-adult animals, respectively. The results obtained could be important for the further development of a non-invasive and less expensive detection method of bovine tuberculosis in wildlife populations.
|
|
| 3. |
- Drozdowska, Katarzyna, et al.
(författare)
-
Combined chemoresistive and in situ FTIR spectroscopy study of nanoporous NiO films for light-activated nitrogen dioxide and acetone gas sensing
- 2022
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 353
-
Tidskriftsartikel (refereegranskat)abstract
- The chemoresistive sensor response of nanoporous NiO films prepared by advanced gas deposition was investigated by combined resistivity and in situ FTIR spectroscopy, with and without simultaneous light illumination, to detect NO2 and acetone gases. The sensitivity towards NO2 increased dramatically under UV irradiation employing 275 nm light. Improved sensitivity was observed at an elevated temperature of 150 degrees C. In situ FTIR measurements were performed to record the transient gas adsorption/desorption processes. The sustained sensitivity and repeatability for NO2 sensing could be attributed to reversible surface-nitro and nitrate species formation, which are stable on the surface at relative humidity up to 40%. In contrast, acetone sensing results in irreversible decomposition and accumulation of reaction products on the NiO sensor surface, covering the surface and limiting gas sensing. Implications of the study for improved and sustained NiO gas sensor properties in gas mixtures are discussed.
|
|
| 4. |
- Durán-Acevedo, Cristhian Manuel, et al.
(författare)
-
Exhaled breath analysis for gastric cancer diagnosis in Colombian patients.
- 2018
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 9:48, s. 28805-28817
-
Tidskriftsartikel (refereegranskat)abstract
- We present here the first study that directly correlates gastric cancer (GC) with specific biomarkers in the exhaled breath composition on a South American population, which registers one of the highest global incidence rates of gastric affections. Moreover, we demonstrate a novel solid state sensor that predicts correct GC diagnosis with 97% accuracy. Alveolar breath samples of 30 volunteers (patients diagnosed with gastric cancer and a controls group formed of patients diagnosed with other gastric diseases) were collected and analyzed by gas-chromatography/mass-spectrometry (GC-MS) and with an innovative chemical gas sensor based on gold nanoparticles (AuNP) functionalized with octadecylamine ligands. Our GC-MS analyses identified 6 volatile organic compounds that showed statistically significant differences between the cancer patients and the controls group. These compounds were different from those identified in previous studied performed on other populations with high incidence rates of this malady, such as China (representative for Eastern Asia region) and Latvia (representative for Baltic States), attributable to lifestyle, alimentation and genetics differences. A classification model based on principal component analysis of our sensor data responses to the breath samples yielded 97% accuracy, 100% sensitivity and 93% specificity. Our results suggest a new and non-intrusive methodology for early diagnosis of gastric cancer that may be deployed in regions lacking well-developed health care systems as a prediagnosis test for selecting the patients that should undergo deeper investigations (e.g., endoscopy and biopsy).
|
|
| 5. |
- Geremariam Welearegay, Tesfalem, et al.
(författare)
-
Diagnosis of Human Echinococcosis via Exhaled Breath Analysis : A Promise for Rapid Diagnosis of Infectious Diseases Caused by Helminths
- 2019
-
Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 219:1, s. 101-109
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Human echinococcosis is a neglected infectious disease affecting more than 1 million people globally. Its diagnosis is expensive and difficult because of lack of adequate resources in low-resource locations, where most cases occur.Methods: A group of volunteers diagnosed with the 2 main types of echinococcosis and corresponding control groups were recruited from hospitals in Tunisia (32 patients with cystic echinococcosis and 43 controls) and Poland (16 patients with alveolar echinococcosis and 8 controls). Breath samples were collected from all patients and analyzed by gas chromatography coupled to mass spectrometry, and a specifically developed electronic nose system.Results: The chemical analysis revealed statistically different concentrations of 2 compounds in the breath of patients with cystic echinococcosis compared to controls, and statistically different concentrations of 7 compounds in the breath of patients with alveolar echinococcosis compared to controls. The discrimination accuracy achieved by the electronic nose system was 100% for cystic echinococcosis and 92.9% for alveolar echinococcosis, while the discrimination accuracy between these 2 patient groups was 92.1%.Conclusion: Here we advocate a noninvasive, fast, easy-to-operate and nonexpensive diagnostic tool for the diagnosis of human echinococcosis disease through exhaled breath analysis, suitable for early diagnosis and population screening.
|
|
| 6. |
- Geremariam Welearegay, Tesfalem, et al.
(författare)
-
Fabrication and characterisation of ligand-functionalised ultrapure monodispersed metal nanoparticle nanoassemblies employing advanced gas deposition technique
- 2018
-
Ingår i: Nanotechnology. - : IOP PUBLISHING LTD. - 0957-4484 .- 1361-6528. ; 29:6
-
Tidskriftsartikel (refereegranskat)abstract
- Here, we report for the first time the fabrication of ligand-functionalised ultrapure monodispersed metal nanoparticles (Au, Cu, and Pt) from their pure metal precursors using the advanced gas deposition technique. The experimental conditions during nanoparticle formation were adjusted in order to obtain ultrafine isolated nanoparticles on different substrates. The morphology and surface analysis of the as-deposited metal nanoparticles were investigated using scanning electron microscopy, x-ray diffraction and Fourier transform infra-red spectroscopy, which demonstrated the formation of highly ordered pure crystalline nanoparticles with a relatively uniform size distribution of similar to 10 nm (Au), similar to 4 nm (Cu) and similar to 3 nm (Pt), respectively. A broad range of organic ligands containing thiol or amine functional groups were attached to the nanoparticles to form continuous networks of nanoparticle-ligand nanoassemblies, which were characterised by scanning electron microscopy and x-ray photoelectron spectroscopy. The electrical resistance of the functional nanoassemblies deposited in the gap spacing of two microfabricated parallel Au electrodes patterned on silicon substrates ranged between tens of k Omega and tens of M Omega, which is suitable for use in many applications including (bio)chemical sensors, surface-enhanced Raman spectroscopy and molecular electronic rectifiers.
|
|
| 7. |
- Ionescu, Radu, et al.
(författare)
-
Fabrication of ultra-pure gold nanoparticles capped with dodecanethiol for Schottky-diode chemical gas sensing devices
- 2017
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 239, s. 455-461
-
Tidskriftsartikel (refereegranskat)abstract
- Ultra-pure monolayer-capped gold nanoparticles for chemical gas sensing devices were prepared by a novel two-step process: a physical vapour deposition technique was first employed to make dispersed ultra-pure size-controlled gold nanoparticles, and this step was followed by a coating process for functionalization of the gold nanoparticles with an organic ligand, specifically dodecanethiol. X-ray photoelectron spectroscopy proved that the nano-assemblies had high purity. Chemical sensing devices based on these nano-assemblies showed Schottky-diode behaviour. We believe this is the first observation of Schottky-diodes fabricated from nanomaterials based on metallic nanoparticles. Gas sensing experiments demonstrated that these devices were suitable for detecting volatile organic compounds.
|
|
| 8. |
- Jaimes-Mogollon, Aylen Lisset, et al.
(författare)
-
Review on Volatolomic Studies as a Frontier Approach in Animal Research
- 2021
-
Ingår i: Advanced Biology. - : John Wiley & Sons. - 2701-0198. ; 5:6
-
Forskningsöversikt (refereegranskat)abstract
- This paper presents a comprehensive review of the research studies in volatolomics performed on animals so far. At first, the procedures proposed for the collection, preconcentration, and storing of the volatile organic compounds emitted by various biological samples of different animals are presented and discussed. Next, the results obtained in the analysis of the collected volatile samples with analytical equipment are shown. The possible volatile biomarkers identified for various diseases are highlighted for different types of diseases, animal species, and biological samples analyzed. The chemical classes of these compounds, as well as the biomarkers found in a higher number of animal diseases, are indicated, and their possible origin is analyzed. The studies that dealt with the diagnosis of various diseases from sample measurement with electronic nose systems are also presented and discussed. The paper ends with a final remark regarding the necessity of optimization and standardization of sample collection and analysis procedures for obtaining meaningful results.
|
|
| 9. |
- Kwiatkowski, Andrzej, et al.
(författare)
-
Assessment of Electronic Sensing Techniques for the Rapid Identification of Alveolar Echinococcosis through Exhaled Breath Analysis
- 2020
-
Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 20:9
-
Tidskriftsartikel (refereegranskat)abstract
- Here we present a proof-of-concept study showing the potential of a chemical gas sensors system to identify the patients with alveolar echinococcosis disease through exhaled breath analysis. The sensors system employed comprised an array of three commercial gas sensors and a custom gas sensor based on WO3 nanowires doped with gold nanoparticles, optimized for the measurement of common breath volatile organic compounds. The measurement setup was designed for the concomitant measurement of both sensors DC resistance and AC fluctuations during breath samples exposure. Discriminant Function Analysis classification models were built with features extracted from sensors responses, and the discrimination of alveolar echinococcosis was estimated through bootstrap validation. The commercial sensor that detects gases such as alkane derivatives and ethanol, associated with lipid peroxidation and intestinal gut flora, provided the best classification (63.4% success rate, 66.3% sensitivity and 54.6% specificity) when sensors’ responses were individually analyzed, while the model built with the AC features extracted from the responses of the cross-reactive sensors array yielded 90.2% classification success rate, 93.6% sensitivity and 79.4% specificity. This result paves the way for the development of a noninvasive, easy to use, fast and inexpensive diagnostic test for alveolar echinococcosis diagnosis at an early stage, when curative treatment can be applied to the patients.
|
|
| 10. |
- Kwiatkowski, Andrzej, et al.
(författare)
-
Enhanced visible light-activated gas sensing properties of nanoporous copper oxide thin films
- 2024
-
Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 273
-
Tidskriftsartikel (refereegranskat)abstract
- Metal oxide gas sensors are popular chemoresistive sensors. They are used for numerous tasks, including environmental and safety monitoring. Some gas-sensing materials exhibit photo-induced properties that can be utilized for enhanced gas detection by modifying the sensor selectivity and sensitivity when illuminated by light. Here, we present the gas sensing characteristics of highly nanoporous Cu2O thin films towards both electrophilic (NO2) and nucleophilic (C2H5OH, NH3) gas molecules under ambient temperature and modulated by visible light illumination of different colors (red: 632 nm, green: 530 nm, blue: 468 nm). Cu2O films were fabricated by reactive advanced gas deposition (AGD) technology. The surface and structural analysis of the samples confirm the deposition of nanoporous thin films of mixed copper oxide phases. The gas sensing property of Cu2O exhibited expected p-type semiconductor behavior upon electrophilic and nucleophilic gas exposures. Our results show that visible light illumination provides enhanced sensor response.
|
|
| 11. |
- Montero Amenedo, José, 1983-, et al.
(författare)
-
Copper-zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method
- 2021
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:17, s. 10224-10234
-
Tidskriftsartikel (refereegranskat)abstract
- Heterojunction copper-zinc oxide catalysts were prepared by a hybrid two-step methodology comprising hydrothermal growth of ZnO nanorods (ZnO-NR) followed by deposition of Cu2O nanoparticles using an advanced gas deposition technique (AGD). The obtained bicatalysts were characterized by SEM, AFM, XRD, XPS, PL and spectrophotometry and revealed well-dispersed and crystalline Cu2O nanoparticles attached to the ZnO-NR. The adsorption properties and photocatalytic degradation of Orange II dye in water solutions were measured. It was found that the bicatalysts exhibited a conversion rate and quantum yield that both were about 50% higher compared with ZnO-NR alone, which were attributed to the intrinsic electric field created at the p-n junction formed at the Cu2O/ZnO interface facilitating charge separation of electron-hole pairs formed upon interband photon absorption. The interpretation was evidenced by efficient quenching of characteristic deep level ZnO photoluminescence bands and photoelectron core-level energy shifts. By comparisons with known energy levels in Cu2O and ZnO, the effect was found to be most pronounced for the non-polar ZnO-NR side facets, which accounted for about 95% of the exposed surface area of the catalyst and hence the majority of dye adsorption. It was also found that the dye adsorption capacity of the ZnO nanorods increased considerably after Cu2O deposition thereby facilitating the oxidation of the dye. The results imply the possibility of judiciously aligning band edges on structurally controlled and well-connected low-dimensional semiconductor nanostructures using combined two-step synthesis techniques, where in particular vacuum-based techniques such as AGD allow for growth of well-connected nanocrystals with well developed heterojunction interfaces.
|
|
| 12. |
- Nol, Pauline, et al.
(författare)
-
Evaluation of Volatile Organic Compounds Obtained from Breath and Feces to Detect Mycobacterium tuberculosis Complex in Wild Boar (Sus scrofa) in Donana National Park, Spain
- 2020
-
Ingår i: Pathogens. - : MDPI AG. - 2076-0817. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of Mycobacterium tuberculosis complex (MTBC) in wild swine, such as in wild boar (Sus scrofa) in Eurasia, is cause for serious concern. Development of accurate, efficient, and noninvasive methods to detect MTBC in wild swine would be highly beneficial to surveillance and disease management efforts in affected populations. Here, we describe the first report of identification of volatile organic compounds (VOC) obtained from the breath and feces of wild boar to distinguish between MTBC-positive and MTBC-negative boar. We analyzed breath and fecal VOC collected from 15 MTBC-positive and 18 MTBC-negative wild boar in Donana National Park in Southeast Spain. Analyses were divided into three age classes, namely, adults (>2 years), sub-adults (12-24 months), and juveniles (<12 months). We identified significant compounds by applying the two-tailed statistical t-test for two samples assuming unequal variance, with an alpha value of 0.05. One statistically significant VOC was identified in breath samples from adult wild boar and 14 were identified in breath samples from juvenile wild boar. One statistically significant VOC was identified in fecal samples collected from sub-adult wild boar and three were identified in fecal samples from juvenile wild boar. In addition, discriminant function analysis (DFA) was used to build classification models for MTBC prediction in juvenile animals. Using DFA, we were able to distinguish between MTBC-positive juvenile wild boar and MTBC-negative juvenile wild boar using breath VOC or fecal VOC. Based on our results, further research is warranted and should be performed using larger sample sizes, as well as wild boar from various geographic locations, to verify these compounds as biomarkers for MTBC infection in this species. This new approach to detect MTBC infection in free-ranging wild boar potentially comprises a reliable and efficient screening tool for surveillance in animal populations.
|
|
| 13. |
- Padilla, Marta, et al.
(författare)
-
Overview on VOGAS : an instrument combining two gas sensing techniques for disease diagnosis
- 2022
-
Ingår i: 2022 IEEE INTERNATIONAL SYMPOSIUM ON OLFACTION AND ELECTRONIC NOSE (ISOEN 2022). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665458603
-
Konferensbidrag (refereegranskat)abstract
- We present VOGAS, a semi-portable instrument performing non-invasive and fast detection of gastric cancer. The VOGAS device analyzes the patients exhaled breath using two gas sensing techniques: infrared spectrometry and different technologies of resistive gas sensors (gold nanoparticles, research developed metal oxides and commercial metal oxides). The combination of these techniques results in a great amount of complementary information in a single breath sample measurement, which can increase the ability of a one-gas sensing technique device to detect gastric diseases. In this work, we describe the VOGAS device in detail.
|
|
| 14. |
- Saidi, Tarik, et al.
(författare)
-
Exhaled breath gas sensing using pristine and functionalized WO3 nanowire sensors enhanced by UV-light irradiation
- 2018
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 273, s. 1719-1729
-
Tidskriftsartikel (refereegranskat)abstract
- The development of advanced metal-oxide-semiconductor sensing technologies for the detection of Volatile Organic Compounds (VOCs) present in exhaled breath is of great importance for non-invasive, cheap and fast medical diagnostics. Our experimental studies investigate the effects of operating temperature selection and UV-light irradiation on improving the response of WO3 nanowire sensors towards exhaled breath exposure. Herein, six WO3 nanowire sensors (both pristine and doped with a range of metal nanoparticles such as Pt, Au, Au/Pt, Ni and Fe) were synthesised via Aerosol-Assisted Chemical Vapour Deposition (AACVD) and characterized by means of Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX-ray). Breath measurements were performed in the dark and under UV-light irradiation at various sensor operating temperatures. The results demonstrate that UV-light irradiation combined with the optimisation of the sensors' operating temperature can greatly enhance the sensors' responses towards breath exposure.
|
|
| 15. |
- Saidi, Tarik, et al.
(författare)
-
Non-invasive prediction of lung cancer histological types through exhaled breath analysis by UV-irradiated electronic nose and GC/QTOF/MS
- 2020
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 311
-
Tidskriftsartikel (refereegranskat)abstract
- Lung cancer (LC) is one of the most lethal diseases from the last decades. Accurate diagnosis of LC histology could lead to the prescription of personalized medical treatment to the affected subjects, which could reduce the mortality rate. We present here an experimental study performed in the pulmonology units of three hospitals from Morocco to non-invasively detect LC and predict LC histology via the analysis of the volatile organic compounds (VOCs) emitted through breathing. Gas chromatography coupled to a quadrupole time-of-flight mass spectrometer (GC/QTOF/MS) employed to detect the breath VOCs, revealed 30 discriminative VOCs in the breath of healthy subjects and LC patients; among them, 4 unique breath VOCs were found for the first time in the breath of LC patients, and could be used as new biomarkers for future LC diagnosis. Besides, an electronic nose (e-nose) system using a novel sensing technique in breath analysis, based on UV-irradiation of the gas sensors, was employed to characterize the overall composition of the collected breath samples, providing a satisfactory discrimination between the breath patterns of LC patients and healthy subjects. Importantly, the e-nose could further discriminate with high accuracy between the two types of LC (non-small cell LC and small cell LC), as well as between two of the major subtypes of non-small cell LC, namely squamous cell carcinoma (SCC) and adenocarcinoma (ADC). The reported results prove that breath analysis with chemical gas sensors and analytical techniques can provided an accurate mean for the non-invasive diagnosis of LC and LC histology.
|
|
| 16. |
- Smulko, J., et al.
(författare)
-
Low-frequency noise in Au-decorated graphene-Si Schottky barrier diode at selected ambient gases
- 2023
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 122:21
-
Tidskriftsartikel (refereegranskat)abstract
- We report results of the current-voltage characteristics and low-frequency noise in Au nanoparticle (AuNP)-decorated graphene-Si Schottky barrier diodes. Measurements were conducted in ambient air with addition of either of two organic vapors, tetrahydrofuran [(CH2)(4)O; THF] and chloroform (CHCl3), as also during yellow light illumination (592 nm), close to the measured particle plasmon polariton frequency of the Au nanoparticle layer. We observed a shift of the DC characteristics at forward voltages (forward resistance region) when tetrahydrofuran vapor was admitted (in a Au-decorated graphene-Si Schottky diode), and a tiny shift under yellow irradiation when chloroform was added (in not decorated graphene-Si Schottky diode). Significantly larger difference in the low-frequency noise was observed for the two gases during yellow light irradiation, compared with no illumination. The noise intensity was suppressed by AuNPs when compared with noise in graphene-Si Schottky diode without an AuNP layer. We conclude that flicker noise generated in the investigated Au-decorated Schottky diodes can be utilized for gas detection.
|
|
| 17. |
- Sorar, Idris, et al.
(författare)
-
Electrochromism in Ni Oxide Thin Films Made by Advanced Gas Deposition and Sputtering : A Comparative Study Demonstrating the Significance of Surface Effects
- 2020
-
Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 167:11
-
Tidskriftsartikel (refereegranskat)abstract
- Films of electrochromic Ni oxide, with thickness in the ∼100–1000-nm range, were prepared by reactive advanced gas deposition (AGD) and, for comparison, also by reactive DC magnetron sputtering (MS). Voltammetric cycling was performed in an electrolyte of lithium perchlorate in propylene carbonate in the voltage range 2.0–4.1 V vs Li/Li+, and concurrent optical transmittance modulation was studied at a wavelength of 530 nm. For the thickest films, the optical modulation range was as large as ∼54% and the maximum transmittance was ∼82% for deposition by AGD, whereas the corresponding numbers were ∼45% and ∼87% for MS. Rutherford backscattering spectrometry together with measurements of film thickness demonstrated that the porosity of 400–500-nm-thick films made by AGD and MS were ∼84% and ∼45%, respectively. The charge exchange per mass unit was as high as 48–67 C g–1 for samples made by AGD. The corresponding number was much lower for MS, namely 13–18 C g–1. These results lend convincing support to the view that the electrochromism of Ni-oxide-based films in Li-ion-conducting electrolytes is dominated by surface effects.
|
|
| 18. |
- Welearegay, Tesfalem, et al.
(författare)
-
Exhaled air analysis as a potential fast method for early diagnosis of dengue disease
- 2020
-
Ingår i: Sensors and actuators. B, Chemical. - Netherlands : Elsevier BV. - 0925-4005 .- 1873-3077. ; 310
-
Tidskriftsartikel (refereegranskat)abstract
- Dengue is a neglected tropical disease caused by arbovirus. Every year 390 million persons are infected with dengue, of which 96 million manifest clinically around the world, mainly in the Latin America, South-East Asia and Western Pacific. The disease manifests itself as a flu-like infection that generally is difficult to recognise from a normal flu or other viral infections. The mortality rate is around 20 % for the severe form of dengue, which readily could be decreased to below 1% with early, reliable diagnostic tools. Today there exist however no diagnostic tests for the early and rapid diagnosis of this disease. In this study, we report for the first time the possibility of identification of possible biomarkers associated with dengue disease in the exhaled air, and of the development of a breath test for fast, non-invasive and easy diagnosis of this disease. Further, we demonstrate a new deployable sensor technology based on a chemoresistive metal-ligand nanoassembly tailored for the identified possible biomarkers of dengue disease, which achieved 100 % accuracy for dengue diagnosis on our study group and can be used in both specialist and non-specialist settings. Nevertheless, as the present study was performed on a limited number of patients because of the difficulty to recruit a high number of patients because dengue is a neglected disease, future validation tests on a higher cohort are necessary for corroborating the results obtained in the present study.
|
|
| 19. |
- Welearegay, Tesfalem Geremariam, et al.
(författare)
-
Ligand-Capped Ultrapure Metal Nanoparticle Sensors for the Detection of Cutaneous Leishmaniasis Disease in Exhaled Breath
- 2018
-
Ingår i: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 3:12, s. 2532-2540
-
Tidskriftsartikel (refereegranskat)abstract
- Human cutaneous leishmaniasis, although designated as one of the most neglected tropical diseases, remains underestimated due to its misdiagnosis. The diagnosis is mainly based on the microscopic detection of amastigote forms, isolation of the parasite, or the detection of LeishmaniaDNA, in addition to its differential clinical characterization; these tools are not always available in routine daily practice, and they are expensive and time-consuming. Here, we present a simple-to-use, noninvasive approach for human cutaneous leishmaniasis diagnosis, which is based on the analysis of volatile organic compounds in exhaled breath with an array of specifically designed chemical gas sensors. The study was realized on a group of n = 28 volunteers diagnosed with human cutaneous leishmaniasis and a group of n = 32 healthy controls, recruited in various sites from Tunisia, an endemic country of the disease. The classification success rate of human cutaneous leishmaniasis patients achieved by our sensors test was 98.2% accuracy, 96.4% sensitivity, and 100% specificity. Remarkably, one of the sensors, based on CuNPs functionalized with 2-mercaptobenzoxazole, yielded 100% accuracy, 100% sensitivity, and 100% specificity for human cutaneous leishmaniasis discrimination. While AuNPs have been the most extensively used in metal nanoparticle–ligand sensing films for breath sensing, our results demonstrate that chemical sensors based on ligand-capped CuNPs also hold great potential for breath volatile organic compounds detection. Additionally, the chemical analysis of the breath samples with gas chromatography coupled to mass spectrometry identified nine putative breath biomarkers for human cutaneous leishmaniasis.
|
|
| 20. |
- Welearegay, Tesfalem, et al.
(författare)
-
Pristine, Au and Cu Decorated Nanoporous NiO Films for Selective CO and NO2 Gas Sensing
- 2023
-
Ingår i: 2023 IEEE SENSORS. - : IEEE. - 9798350303872
-
Konferensbidrag (refereegranskat)abstract
- We report on a one-step, on-chip fabrication process of high-quality nanoporous p-type NiO thin films for gas sensing application. Highly nanoporous and polycrystalline NiO thin films were fabricated and deposited onto alumina substrates employing advanced gas deposition (AGD) technique. AGD-fabricated NiO films were further decorated with gold (AuNP) and copper (CuNP) nanoparticles, respectively. The nano-sensors array thus fabricated were integrated into a purpose-built hybrid senor unit that allows for in-situ conditioning and gas sensing measurement of volatile gases. The results revealed that the relative sensor responses of pure NiO towards CO gas exposures (reducing gas), were higher than the corresponding NP decorated NiO films. In contrast, AuNP decorated NiO sensors exhibited relatively higher sensor response towards oxidizing gases, NO2, than CuNP decorated and pure NiO based nano-sensors. It is noted that the relative sensor response changes are mainly governed by the high porosity of the as-fabricated NiO films and the corresponding grain-grain Schottky barriers. Limits of detection (LOD) was estimated to be 1.5 ppm for CO and 400 ppb for NO2 for pure and AuNP decorated NiO based sensors, respectively. The results are promising for further development of nanoporous p-type metal oxide sensors for specific volatile biomarkers detection, for example, in exhaled breath analysis for disease diagnosis.
|
|
