| 1. |
- Kreij, Karl, 1975-, et al.
(author)
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On-line detection of microbial contaminations in animal cell reactor cultures using an electronic nose device
- 2005
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In: Cytotechnology (Dordrecht). - : Springer Science and Business Media LLC. - 0920-9069 .- 1573-0778. ; 48:1-3, s. 41-58
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Journal article (peer-reviewed)abstract
- An electronic nose (EN) device was used to detect microbial and viral contaminations in a variety of animal cell culture systems. The emission of volatile components from the cultures accumulated in the bioreactor headspace, was sampled and subsequently analysed by the EN device. The EN, which was equipped with an array of 17 chemical gas sensors of varying selectivity towards the sampled volatile molecules, generated response patterns of up to 85 computed signals. Each 15 or 20 min a new gas sample was taken generating a new response pattern. A software evaluation tool visualised the data mainly by using principal component analysis. The EN was first used to detect microbial contaminations in a Chinese hamster ovary (CHO) cell line producing a recombinant human macrophage colony stimulating factor (rhM-CSF). The CHO cell culture was contaminated by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida utilis which all were detected. The response patterns from the CHO cell culture were compared with monoculture references of the microorganisms. Second, contaminations were studied in an Sf-9 insect cell culture producing another recombinant protein (VP2 protein). Contaminants were detected from E. coli, a filamentous fungus and a baculovirus. Third, contamination of a human cell line, HEK-293, infected with E. coli exhibited comparable results. Fourth, bacterial contaminations could also be detected in cultures of a MLV vector producer cell line. Based on the overall experiences in this study it is concluded that the EN method has in a number of cases the potential to be developed into a useful on-line contamination alarm in order to support safety and economical operation for industrial cultivation. © Springer 2005.
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| 2. |
- Padilla, Marta, et al.
(author)
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Overview on VOGAS : an instrument combining two gas sensing techniques for disease diagnosis
- 2022
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In: 2022 IEEE INTERNATIONAL SYMPOSIUM ON OLFACTION AND ELECTRONIC NOSE (ISOEN 2022). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665458603
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Conference paper (peer-reviewed)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.
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| 3. |
- Welearegay, Tesfalem, et al.
(author)
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Pristine, Au and Cu Decorated Nanoporous NiO Films for Selective CO and NO2 Gas Sensing
- 2023
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In: 2023 IEEE SENSORS. - : IEEE. - 9798350303872
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Conference paper (peer-reviewed)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.
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