Sodium Dodecyl Sulfate

Sodium dodecyl sulphate (SDS), an anionic surfactant that mimics some characteristics of biological membrane has also been found to induce aggregation in proteins. The present study was carried out on 25 diverse proteins using circular dichroism, fluorescence spectroscopy, dye binding assay and electron microscopy. It was found that an appropriate molar ratio of protein to SDS readily induced amyloid formation in all proteins at a pH below two units of their respective isoelectric points (pI) while no aggregation was observed at a pH above two units of pI. We also observed that electrostatic interactions play a leading role in the induction of amyloid. This study can be used to design or hypothesize a molecule or drug, which may counter act the factor responsible for amyloid formation.

The structure of a self-assembly formed from a cationic azobenzene derivative, 4-cholesterocarbonyl-4'-(N,N,N-triethylamine butyloxyl bromide) azobenzene (CAB) and surfactant sodium dodecyl sulfate (SDS) in aqueous solution was studied by cryo-TEM and synchrotron radiation small-angle X-ray scattering (SAXS). Both unilamellar and multilamellar vesicles could be observed. CAB in vesicles were capable to undergo reversible trans-to-cis isomerization upon UV or visible light irradiation. The structural change upon UV light irradiation could be catched by SAXS, which demonstrated that the interlamellar spacing of the cis-multilamellar vesicles increased by 0.2-0.3 nm. Based on this microstructural change, the release of rhodamine B (RhB) and doxorubicin (DOX) could be triggered by UV irradiation. When incubated NIH 3T3 cells and Bel 7402 cells with DOX-loaded CAB/SDS vesicles, UV irradiation induced DOX release decreased the viability of both cell lines significantly compared with the non-irradiated cells. The in vitro experiment indicated that CAB/SDS vesicles had high efficiency to deliver loaded molecules into cells. The in vivo experiment showed that CAB/SDS vesicles not only have high drug delivery efficiency into rat retinas, but also could maintain high drug concentration for a longer time. CAB/SDS catanionic vesicles may find potential applications as a smart drug delivery system for controlled release by light.

Sodium dodecyl sulfate is a detergent that disrupts cell membranes, activates cell wall integrity signaling and restricts cell growth in Saccharomyces cerevisiae. However, the underlying mechanism of how sodium dodecyl sulfate inhibits cell growth is not fully understood. Previously, we have shown that deletion of the MCK1 gene leads to sensitivity to sodium dodecyl sulfate; thus, we implemented a suppressor gene screening revealing that the overexpression of TAT2 tryptophan permease rescues cell growth in sodium dodecyl sulfate-treated Δmck1 cells. Therefore, we questioned the involvement of tryptophan in the response to sodium dodecyl sulfate treatment. In this work, we show that trp1-1 cells have a disadvantage in the response to sodium dodecyl sulfate compared to auxotrophy for adenine, histidine, leucine or uracil when cells are grown on rich media. While also critical in the response to tea tree oil, TRP1 does not avert growth inhibition due to other cell wall/membrane perturbations that activate cell wall integrity signaling such as Calcofluor White, Congo Red or heat stress. This implicates a distinction from the cell wall integrity pathway and suggests specificity to membrane stress as opposed to cell wall stress. We discovered that tyrosine biosynthesis is also essential upon sodium dodecyl sulfate perturbation whereas phenylalanine biosynthesis appears dispensable. Finally, we observe enhanced tryptophan import within minutes upon exposure to sodium dodecyl sulfate indicating that these cells are not starved for tryptophan. In summary, we conclude that internal concentration of tryptophan and tyrosine makes cells more resistant to detergent such as sodium dodecyl sulfate.

BackgroundEpithelial barrier disruption is a hallmark of allergic skin diseases. Sodium dodecyl sulfate (SDS), a surfactant in household cleaning products, is known to impair the barrier.MethodsWe used a physiologically relevant ex vivo human skin combined with real-time electrical impedance spectroscopy (EIS) to monitor barrier integrity after SDS exposure. Multi-omics analyses, including RNA sequencing and proximity extension-based proteomics, characterized molecular responses. Barrier permeability and oxidative stress were evaluated in primary keratinocytes, and the protective effects of N-acetylcysteine (NAC) and nicotinamide (NAM) were assessed in both air-liquid interface keratinocyte cultures and ex vivo skins.ResultsEven a 1-min SDS exposure caused a rapid EIS decline, indicating immediate barrier compromise. 5-min exposures produced dose-dependent EIS decline with broad suppression of barrier and immune mediators (e.g., CXCL11, MCP4, and HNMT), 6-h exposure sustained skin barrier loss and associated inflammatory and remodeling programs. Proteomic signatures highlighted AREG, JUN, and ITGA6 can track skin damage, while CST5 and PRDX1 correlated with the preservation. Transcriptomics corroborated these changes, showing up-regulation of stress and repair programs-endoplasmic reticulum stress, oxidative stress, sphingolipid biosynthesis, and epidermal differentiation pathways. NAC/NAM reduced SDS-induced reactive oxygen species, cytotoxicity, and permeability in primary keratinocytes, and restored EIS values in ex vivo skin.ConclusionShort-term SDS exposure rapidly disrupts human skin barrier integrity through oxidative stress-driven suppression of structural/immune mediators and activation of stress/remodeling pathways. NAC and NAM effectively mitigated damages, highlighting antioxidants as preventive interventions for surfactant-induced skin barrier dysfunction.