A lab-on-a-chip utilizing microwaves for bacterial spore disruption and detection

Valijam, Shayan; Nilsson, Daniel P G; Öberg, Rasmus; Jonsmoen, Unni Lise; Porch, Adrian; Andersson, Magnus; Malyshev, Dmitry

doi:10.1016/j.bios.2023.115284

Cited by 4 publications

(2 citation statements)

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“…difficile . As an alternative to this, spectroscopic techniques such as fluorescence and Raman spectroscopies offer a rapid option for following chemical changes in spores, as well as following processes relevant to spore viability, for example, germination. − Fluorescence spectroscopy can detect the presence of amino acids like tryptophan and tyrosine, and the fluorescence intensity is a good marker when spore protein structures break down. , Similarly, Raman spectroscopy can detect the relative presence of amino acids and indicate the presence of DNA or DPA release. , Raman spectroscopy can also utilize deuterium oxide (heavy water) as a marker and follow specific spore-related processes such as germination and outgrowth …”

Section: Introductionmentioning

confidence: 99%

“… 15 − 19 Fluorescence spectroscopy can detect the presence of amino acids like tryptophan and tyrosine, and the fluorescence intensity is a good marker when spore protein structures break down. 15 , 20 Similarly, Raman spectroscopy can detect the relative presence of amino acids and indicate the presence of DNA or DPA release. 17 , 18 Raman spectroscopy can also utilize deuterium oxide (heavy water) as a marker and follow specific spore-related processes such as germination and outgrowth.…”

Section: Introductionmentioning

confidence: 99%

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UV-Induced Spectral and Morphological Changes in Bacterial Spores for Inactivation Assessment

Öberg,

Sil,

Johansson

et al. 2024

J. Phys. Chem. B

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The ability to detect and inactivate spore-forming bacteria is of significance within, for example, industrial, healthcare, and defense sectors. Not only are stringent protocols necessary for the inactivation of spores but robust procedures are also required to detect viable spores after an inactivation assay to evaluate the procedure's success. UV radiation is a standard procedure to inactivate spores. However, there is limited understanding regarding its impact on spores' spectral and morphological characteristics. A further insight into these UV-induced changes can significantly improve the design of spore decontamination procedures and verification assays. This work investigates the spectral and morphological changes to Bacillus thuringiensis spores after UV exposure. Using absorbance and fluorescence spectroscopy, we observe an exponential decay in the spectral intensity of amino acids and protein structures, as well as a logistic increase in dimerized DPA with increased UV exposure on bulk spore suspensions. Additionally, using micro-Raman spectroscopy, we observe DPA release and protein degradation with increased UV exposure. More specifically, the protein backbone's 1600−1700 cm −1 amide I band decays slower than other amino acid-based structures. Last, using electron microscopy and light scattering measurements, we observe shriveling of the spore bodies with increased UV radiation, alongside the leaking of core content and disruption of proteinaceous coat and exosporium layers. Overall, this work utilized spectroscopy and electron microscopy techniques to gain new understanding of UV-induced spore inactivation relating to spore degradation and CaDPA release. The study also identified spectroscopic indicators that can be used to determine spore viability after inactivation. These findings have practical applications in the development of new spore decontamination and inactivation validation methods.

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