pH-induced changes in Raman, UV–vis absorbance, and fluorescence spectra of dipicolinic acid (DPA)

Malyshev, Dmitry; Öberg, Rasmus; Landström, Lars; Andersson, Per Ola; Dahlberg, Tobias; Andersson, Magnus

doi:10.1016/j.saa.2022.120869

Cited by 16 publications

(8 citation statements)

References 31 publications

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“…We measured the DPA content of the supernatant of spore suspensions using fluorescence spectroscopy. Using the same concentration of spores and water as a buffer ensures that the fluorescence response of DPA is not affected by changes in pH [ 33 ]. The DPA signal from the spores was enhanced using terbium, which makes a complex with DPA [ 34 , 35 ], boosting its fluorescence yield.…”

Section: Resultsmentioning

confidence: 99%

Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes

et al. 2023

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Background Clostridioides difficile is a spore forming bacterial species and the major causative agent of nosocomial gastrointestinal infections. C. difficile spores are highly resilient to disinfection methods and to prevent infection, common cleaning protocols use sodium hypochlorite solutions to decontaminate hospital surfaces and equipment. However, there is a balance between minimising the use of harmful chemicals to the environment and patients as well as the need to eliminate spores, which can have varying resistance properties between strains. In this work, we employ TEM imaging and Raman spectroscopy to analyse changes in spore physiology in response to sodium hypochlorite. We characterize different C. difficile clinical isolates and assess the chemical’s impact on spores’ biochemical composition. Changes in the biochemical composition can, in turn, change spores’ vibrational spectroscopic fingerprints, which can impact the possibility of detecting spores in a hospital using Raman based methods. Results We found that the isolates show significantly different susceptibility to hypochlorite, with the R20291 strain, in particular, showing less than 1 log reduction in viability for a 0.5% hypochlorite treatment, far below typically reported values for C. difficile. While TEM and Raman spectra analysis of hypochlorite-treated spores revealed that some hypochlorite-exposed spores remained intact and not distinguishable from controls, most spores showed structural changes. These changes were prominent in B. thuringiensis spores than C. difficile spores. Conclusion This study highlights the ability of certain C. difficile spores to survive practical disinfection exposure and the related changes in spore Raman spectra that can be seen after exposure. These findings are important to consider when designing practical disinfection protocols and vibrational-based detection methods to avoid a false-positive response when screening decontaminated areas. Graphical Abstract

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Section: Resultsmentioning

confidence: 99%

Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes

et al. 2023

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“…The observed changes in the Raman spectrum reflected the change in molecular structure, the ionic structure, as the pH varied between pH 8.61 to pH 6.91 and then to 7.33 and finally 8.47 [20]. The variation of the ionic form in alcohols ethoxylated with pH of their ethanolic solutions as well as of their aqueous solution, have influenced the electronic structure of the molecule, the ratio of its ionic forms, and thus its spectroscopic response.…”

Section: Alcohols Ethoxylated Raman Spectrum Changes With Phmentioning

confidence: 94%

Measurement of Raman Spectra for Surfactants Contained in a Textile Detergent Product and Three House Washing Detergent Products

Chryssou¹

2022

ACSR

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Four common use detergent products were analyzed and their soluble-insoluble matter ethanolic 95%w/v was determined. Their soluble matter ethanolic was used to acquire their Raman spectra. Their pH values at 298K were measured also. Several Raman bands were related to -C-C-skeletal stretching vibrations in the region between 1000cm -1 and 1150cm -1 , and a peak at 1430cm -1 was related to δ(CH2) deformation for the first detergent product. A band at 1290cm -1 was related to the -SO4 stretch for the surfactant lauryl sulphate. For the alcohols C12-14 ethoxylated sulphated sodium salts in the second detergent product the 1440cm -1 peak was attributed to C-H scissoring. The 1060cm -1 peak was corresponded to -C-C-skeletal stretching of the saturated fatty acid present also. The presence of the aromatic group in the surfactant benzene sulphuric acid C10-13 alkyl derivatives sodium salts was identified at 1615cm -1 in the Raman spectrum of the third detergent product. In the spectrum of the fourth detergent product a peak at 1300cm -1 was attributed to in-phase methylene twisting deformation vibration of the fatty acid sodium oleate. Also, the peaks at 1730cm -1 and at 1270cm -1 were attributed to sodium oleate. Then the alcohols ethoxylated Raman spectrum changes with pH were studied and shifting to longer wavelengths was observed for the second detergent product due to less coupling of the -C-C-stretching vibration to the -C-O-stretching vibration. The ratio of the intensities of anti-Stokes to Stokes lines was found to increase as the temperature increased for 20K for Raman scattering with the 1064nm excitation. Finally, the dissociation energy Do of the bond -C-C-O-in the alcohol C13-15 ethoxylated in the first detergent product was determined to be 386.148449cm-1, or 0.04787507086eV using the Birge-Sponer extrapolation.

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“…Breaking down spores releases the spore DNA (Aslan et al, 2008) and calcium dipicolinic acid (CaDPA) (Celandroni et al, 2004) contained in the spore core, the latter being a protective chemical known to shield the spore core from wet heat (Kong et al, 2012). CaDPA is also a spectroscopic spore biomarker that provides a unique Raman spectral fingerprint and a fluorescence emission signal, which varies between weak and strong depending on the environmental conditions (Malyshev et al, 2022c;Sarasanandarajah et al, 2005). Previous studies have shown that spores can be broken down using microwave applicators.…”

Section: Introductionmentioning

confidence: 99%

A Lab-on-A-Chip Utilizing Microwaves for Bacterial Spore Disruption and Detection

Valijam¹,

Nilsson

Öberg

et al. 2023

Preprint

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pH-induced changes in Raman, UV–vis absorbance, and fluorescence spectra of dipicolinic acid (DPA)

Cited by 16 publications

References 31 publications

Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes

Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes

Measurement of Raman Spectra for Surfactants Contained in a Textile Detergent Product and Three House Washing Detergent Products

A Lab-on-A-Chip Utilizing Microwaves for Bacterial Spore Disruption and Detection

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