Thermal and Alkali Stability of Sodium Dithionite Studied Using ATR-FTIR Spectroscopy

Vegunta, Vijaya Lakshmi; Stevanic, Jasna S.; Lindström, Mikael; Salmén, Lennart

doi:10.15376/biores.12.2.2496-2506

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…68 Depending on concentration, pH, and oxygen access, dithionite shows different reactions. 69 Consequently, the optimization of substance handling and reaction conditions is crucial.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Bilayer Charge Asymmetry and Oil Residues Destabilize Membranes upon Poration

Leomil,

Stephan,

Pramanik

et al. 2024

Langmuir

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Transmembrane asymmetry is ubiquitous in cells, particularly with respect to lipids, where charged lipids are mainly restricted to one monolayer. We investigate the influence of anionic lipid asymmetry on the stability of giant unilamellar vesicles (GUVs), minimal plasma membrane models. To quantify asymmetry, we apply the fluorescence quenching assay, which is often difficult to reproduce, and caution in handling the quencher is generally underestimated. We first optimize this assay and then apply it to GUVs prepared with the inverted emulsion transfer protocol by using increasing fractions of anionic lipids restricted to one leaflet. This protocol is found to produce highly asymmetric bilayers but with ∼20% interleaflet mixing. To probe the stability of asymmetric versus symmetric membranes, we expose the GUVs to porating electric pulses and monitor the fraction of destabilized vesicles. The pulses open macropores, and the GUVs either completely recover or exhibit leakage or bursting/collapse. Residual oil destabilizes porated membranes, and destabilization is even more pronounced in asymmetrically charged membranes. This is corroborated by the measured pore edge tension, which is also found to decrease with increasing charge asymmetry. Using GUVs with imposed transmembrane pH asymmetry, we confirm that poration-triggered destabilization does not depend on the approach used to generate membrane asymmetry.

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“…68 Depending on concentration, pH, and oxygen access, dithionite shows different reactions. 69 Consequently, the optimization of substance handling and reaction conditions is crucial.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Previous reports show that alkaline pH solutions stabilize the dithionite ion. 62,68,69 Therefore, we prepared a 0.1 M sodium dithionite stock solution in 1 M Tris HCl buffer at pH 10. Upon dilution into the vesicle suspension, the solution reached neutral pH.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Bilayer Charge Asymmetry and Oil Residues Destabilize Membranes upon Poration

Leomil,

Stephan,

Pramanik

et al. 2024

Langmuir

View full text Add to dashboard Cite

show abstract

“…The 0.1 M sodium dithionite solution was always freshly prepared and immediately used. Previous reports show that alkaline pH-solutions stabilize the dithionite ion 62,68,69 . Therefore, we prepared the 0.1 M sodium dithionite stock solution in 1 M TrisHCl buffer at pH 10.…”

Section: Optimization Of the Quenching Assaymentioning

confidence: 96%

“…The assay requires precaution, since sodium dithionite is a strong reducing agent and unstable in aqueous solutions 68 . Depending on concentration, pH and oxygen access, dithionite shows different reactions 69 . Consequently, the optimization of substance handling and reaction conditions are crucial.…”

Section: Principle Of the Quenching Assaymentioning

confidence: 99%

Bilayer charge asymmetry and oil residues destabilize membranes upon poration

Leomil

Stephan

Riske

et al. 2023

Preprint

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Membrane asymmetry is ubiquitous in cell membranes particularly with respect to lipids, whereby charged lipids are mainly restricted to the inner monolayer. We investigate the influence of anionic lipid asymmetry on the stability of giant unilamellar vesicles (GUVs), minimal plasma membrane models. To quantify asymmetry, we apply a fluorescence quenching assay, which is often difficult to reproduce and caution in handling the quencher is generally underestimated. Thus, we first optimize this assay and then apply it to GUVs prepared with the inverted emulsion transfer protocol using increasing fractions of anionic lipids restricted to one leaflet. This protocol is found to produce highly asymmetric bilayers, but with ~20% interleaflet mixing. To probe the stability of asymmetric vs symmetric membranes, we expose the GUVs to porating DC pulses and monitor the fraction of destabilized vesicles. The pulses open macropores, and the GUVs either completely recover their integrity or become destabilized exhibiting leakage or bursting/collapse. Destabilization is much more pronounced in asymmetrically charged membranes, which is corroborated by pore edge tension data showing considerable decrease with asymmetry. Rendering GUV membrane asymmetric from exposure to different transmembrane pH, we confirm that poration-triggered destabilization does not depend on the approach used to generate membrane asymmetry.

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“…This results in the inefficient decomposition of Na2S2O4, which is counterproductive for decomposing more active substances for decolorization. Thus, the traditional approach entails inadequate performance and resource waste (Veguta et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Efficient decolorization of reactive dyed cotton fabric with a two-step NaOH/ Na 2 S 2 O 4 process

Wang

et al. 2023

Preprint

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Waste cotton textiles can be decolorized with the NaOH/Na2S2O4 reducing system with mild and effective results. Nevertheless, this system consumes substantial amounts of Na2S2O4, resulting in an inefficient decomposition process. The present study proposed a two-step NaOH/Na2S2O4 method to decolorize the reactive-dyed cotton fabric. The decolorization mechanism of NaOH and Na2S2O4 was investigated based on the decolorization kinetics. The results showed that Na2S2O4 decolorized the dyed cotton fabric more quickly than NaOH. In the reduction system, the decolorization mechanism of NaOH and Na2S2O4 individually followed a three-order kinetic law. During the decolorization process, a hydrolysis reaction between NaOH and cotton fiber destroyed the covalent bond, and a reduction reaction between Na2S2O4 and the dye destroyed the chromophore. The two-step NaOH/Na2S2O4 method improved the decolorization of dyed cotton fabric by reducing the ineffective decomposition of Na2S2O4. Compared to traditional methods, the two-step method endowed the decolorized fabric with a 16% higher CIE L value. Notably, the decolorized cotton fabric retained about 90% of its breaking strength.

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Thermal and Alkali Stability of Sodium Dithionite Studied Using ATR-FTIR Spectroscopy

Cited by 6 publications

References 9 publications

Bilayer Charge Asymmetry and Oil Residues Destabilize Membranes upon Poration

Bilayer Charge Asymmetry and Oil Residues Destabilize Membranes upon Poration

Bilayer charge asymmetry and oil residues destabilize membranes upon poration

Efficient decolorization of reactive dyed cotton fabric with a two-step NaOH/ Na 2 S 2 O 4 process

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