| 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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