| 1. |
- Dietvorst, Jiri, et al.
(author)
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Bacteria Detection at a Single-Cell Level through a Cyanotype-Based Photochemical Reaction
- 2022
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 94:2, s. 787-792
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Journal article (peer-reviewed)abstract
- The detection of living organisms at very low concentrations is necessary for the early diagnosis of bacterial infections, but it is still challenging as there is a need for signal amplification. Cell culture, nucleic acid amplification, or nano-structure-based signal enhancement are the most common amplification methods, relying on long, tedious, complex, or expensive procedures. Here, we present a cyanotype-based photochemical amplification reaction enabling the detection of low bacterial concentrations up to a single-cell level. Photocatalysis is induced with visible light and requires bacterial metabolism of iron-based compounds to produce Prussian Blue. Bacterial activity is thus detected through the formation of an observable blue precipitate within 3 h of the reaction, which corresponds to the concentration of living organisms. The short time-to-result and simplicity of the reaction are expected to strongly impact the clinical diagnosis of infectious diseases.
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| 2. |
- Iyengar, Sharath Narayana, et al.
(author)
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Rapid detection of viable bacteria in whole blood for early sepsis diagnosis and suseptibility testing
- 2021
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In: Proceedings MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 791-792
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Conference paper (peer-reviewed)abstract
- Sepsis is a serious medical condition characterized by a whole-body inflammatory state caused by infection. Here, we present a sepsis method for rapid detection of bacteria from whole blood in less than 5h, combining selective blood cell lysis and a sensitive colorimetric based detection method. Selective cell lysis buffer allows selective rupture of blood cells (5 min), while maintaining bacteria 100% viable. Viable bacteria metabolically reduce iron (III) complexes, initiating a photo-catalytic cascade toward Prussian Blue formation visible to the naked eye. The method is finally validated for antibiotic susceptibility testing.
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| 3. |
- Iyengar, Sharath Narayana, et al.
(author)
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Toward Rapid Detection of Viable Bacteria in Whole Blood for Early Sepsis Diagnostics and Susceptibility Testing
- 2021
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In: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 6:9, s. 3357-3366
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Journal article (peer-reviewed)abstract
- Sepsis is a serious bloodstream infection where the immunity of the host body is compromised, leading to organ failure and death of the patient. In early sepsis, the concentration of bacteria is very low and the time of diagnosis is very critical since mortality increases exponentially with every hour after infection. Common culture-based methods fail in fast bacteria determination, while recent rapid diagnostic methods are expensive and prone to false positives. In this work, we present a sepsis kit for fast detection of bacteria in whole blood, here achieved by combining selective cell lysis and a sensitive colorimetric approach detecting as low as 10(3) CFU/mL bacteria in less than 5 h. Homemade selective cell lysis buffer (combination of saponin and sodium cholate) allows fast processing of whole blood in 5 min while maintaining bacteria alive (100% viability). After filtration, retained bacteria on filter paper are incubated under constant illumination with the electrochromic precursors, i.e., ferricyanide and ferric ammonium citrate. Viable bacteria metabolically reduce iron(III) complexes, initiating a photocatalytic cascade toward Prussian blue formation. As a proof of concept, we combine this method with antibiotic susceptibility testing to determine the minimum inhibitory concentration (MIC) using two antibiotics (ampicillin and gentamicin). Although this kit is used to demonstrate its applicability to sepsis, this approach is expected to impact other key sectors such as hygiene evaluation, microbial contaminated food/beverage, or UTI, among others.
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| 4. |
- Matabuena, Marcos, et al.
(author)
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Identification of Asthma Phenotypes in the Spanish MEGA Cohort Study Using Cluster Analysis
- 2023
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In: Archivos de Bronconeumologia. - : Elsevier BV. - 0300-2896. ; 59:4, s. 223-231
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Journal article (peer-reviewed)abstract
- Introduction: The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes. Methods: We performed a multicentre prospective cohort study, including adult patients with asthma (N = 512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma). A standardised clinical history was completed for each patient. Cluster analysis was performed using the kernel k-groups algorithm. Results: Four clusters were identified. Cluster 1 (31.5% of subjects) includes adult-onset atopic patients with better lung function, lower BMI, good asthma control, low ICS dose, and few exacerbations. Cluster 2 (23.6%) is made of adolescent-onset atopic asthma patients with normal lung function, but low adherence to treatment (59% well-controlled) and smokers (48%). Cluster 3 (17.1%) includes adult-onset patients, mostly severe non-atopic, with overweight, the worse lung function and asthma control, and receiving combination of treatments. Cluster 4 (26.7%) consists of the elderly-onset patients, mostly female, atopic (64%), with high BMI and normal lung function, prevalence of smokers and comorbidities. Conclusion: We defined four phenotypes of asthma using unsupervised cluster analysis. These clusters are clinically relevant and differ from each other as regards FEV1, age of onset, age, BMI, atopy, asthma severity, exacerbations, control, social class, smoking and nasal polyps.
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| 5. |
- Opilski, Zbigniew, et al.
(author)
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Fiber optic humidity sensor based on silk fibroin interference films
- 2020
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In: Photonics Letters of Poland. - : Photonics Society of Poland. - 2080-2242. ; 12:2, s. 49-51
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Journal article (peer-reviewed)abstract
- The article presents an inexpensive and simple method of fiber optic interference relative humidity (RH) sensors based on silk fibroin (SF) films. The sensors were made on standard multimode telecommunications optical fibers using dip-coating method and examined using broadband light sources. The measuring stand at which the basic sensor parameters were measured and the measured parameters were presented.
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| 6. |
- Velarte, Antonio, et al.
(author)
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Fiber-Optic-Based System for High-Resolution Monitoring of Stretch in Excised Tissues
- 2023
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In: Biosensors. - 2079-6374. ; 13:10
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Journal article (peer-reviewed)abstract
- Cardiovascular diseases cause a high number of deaths nowadays. To improve these statistics, new strategies to better understand the electrical and mechanical abnormalities underlying them are urgently required. This study focuses on the development of a sensor to measure tissue stretch in excised tissues, enabling improved knowledge of biomechanical properties and allowing greater control in real time. A system made of biocompatible materials is described, which is based on two cantilevered platforms that integrate an optical fiber inside them to quantify the amount of stretch the tissues are exposed to with a precision of mu m. The operating principle of the sensor is based on the variation of the optical path with the movement of the platforms onto which the samples are fixed. The conducted tests highlight that this system, based on a simple topology and technology, is capable of achieving the desired purpose (a resolution of similar to 1 mu m), enabling the tissue to be bathed in any medium within the system.
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