Effect of mixed surfactants on stratum corneum: a drying stress and Raman spectroscopy study

Novel aspects of Raman spectroscopy in skin research

The analytical technology of Raman spectroscopy has an almost 100‐year history. During this period, many modifications and developments happened in the method like discovery of laser, improvements in optical elements and sensitivity of spectrometer and also more advanced light detection systems. Many types of the innovative techniques appeared (e.g. Transmittance Raman spectroscopy, Coherent Raman Scattering microscopy, Surface‐Enhanced Raman scattering and Confocal Raman spectroscopy/microscopy). This review article gives a short description about these different Raman techniques and their possible applications. Then, a short statistical part is coming about the appearance of Raman spectroscopy in the scientific literature from the beginnings to these days. The third part of the paper shows the main application options of the technique (especially confocal Raman spectroscopy) in skin research, including skin composition analysis, drug penetration monitoring and analysis, diagnostic utilizations in dermatology and cosmeto‐scientific applications. At the end, the possible role of artificial intelligence in Raman data analysis and the regulatory aspect of these techniques in dermatology are briefly summarized. For the future of Raman Spectroscopy, increasing clinical relevance and in vivo applications can be predicted with spreading of non‐destructive methods and appearance with the most advanced instruments with rapid analysis time.

Acute skin barrier disruption alters the secretion of lamellar bodies via the multilayered expression of ABCA12

BACKGROUND

The skin barrier consists of multiple lipid-enriched layers, which are characterized by lamellar repeated structures within the intercellular space. Sodium lauryl sulfate is a well-known substance that can disrupt the skin barrier. The mechanisms underlying the barrier repair process, especially the influence of topical sodium lauryl sulfate treatment on lipid transport in the barrier recovery phase, remain unresolved.

OBJECTIVE

To understand the process of reconstruction of the intercellular lipid layer of the skin after acute barrier disruption by sodium lauryl sulfate treatment in vivo.

METHODS

Female hairless mice were treated with 3 % sodium lauryl sulfate. Transepidermal water loss measurement, histopathological analysis, and gene expression analysis were performed from 1 to 288 h after the topical application of sodium lauryl sulfate. Western blot analysis, immunofluorescence staining, and transmission electron microscopy analysis were performed to examine the expression level of ATP-binding cassette, sub-family A, member 12 (ABCA12), and the secretion level of lamellar bodies.

RESULTS

We observed rapid hyper-keratinization at the stratum corneum and the subsequent concurrent secretion of lamellar bodies into the intercellular space of the stratum corneum during the process of skin barrier recovery. ABCA12 expression associated with lipid transportation into lamellar bodies was transiently upregulated and observed in multiple layers in the upper epidermis, especially in the stratum granulosum.

CONCLUSION

The skin reacts appropriately to maintain its barrier function by first initiating hyper-keratinization and then increasing lamellar body secretion. Activation of ABCA12 is an essential factor for the recovery of skin barrier function.

Excessive cleansing: an underestimating risk factor of rosacea in Chinese population

Appropriate skincare is essential in the prevention and management of rosacea. We sought to investigate whether cleansing habits, the initial step of skin care, would influence the onset and progression of rosacea and their associations with clinical features of rosacea in the Chinese population. We analyzed the daily cleansing habits data collected from 999 rosacea cases and 1010 skin-healthy controls from China. Overall, the high frequency of cleansing (more than once daily) (OR = 1.450) and the large amount of cleansers (> 5 pieces/year) (OR = 1.612) presented a positive correlation with rosacea occurring. The cleansing duration and types of cleansers appeared not to be correlated with the onset of rosacea in this study. Significant risk factors also included the deep cleansing habits, such as the overuse of cleansing tool (more than four times/week) (OR 2.179) and oil control and exfoliating behaviors via daily used products (OR 2.435), facial mask (OR 1.459) or projects in beauty salons (OR 2.688). The analysis of the clinical features of rosacea showed that patients who prefer deep cleansing were more prone to present an initial symptom of papule and pustule (OR 1.63-3.15). What is more, using daily exfoliating products presented a positive correlation with the progression of the symptoms from flushing to erythema (OR = 2.01), papule and pustule (OR = 2.28) and telangiectasis (OR = 2.14), and the affected areas from a single area to pan facial (OR = 1.650). In conclusion, excessive cleansing habits were substantial risk factors for the incidence and progression of rosacea in the Chinese population.

In vivo Raman spectroscopy study on the stimulation mechanism of surfactant

BACKGROUND

Surfactant is widely used in skin care products and cleansers, while it may cause physical discomfort. In this study, in vivo Raman spectroscopy was used to explore surfactant irritation mechanism on skin, which was not found in literature.

METHODS

Sodium dodecyl sulfate (SDS) was chosen to represent surfactant. Research on the negative effect of SDS was undertaken by scanning the two states of the skin (without and with the contact of SDS), respectively, on six volunteers, by means of Raman technique and skin magnifier.

RESULTS

The damage to the surface of normal skin by SDS was visible from the photographs taken by skin magnifier, and the apparent damage matched the damage that was happening underneath the skin elucidated by Raman spectra. Compared to the normal skin, the inter-cellular lipids (ICL) lateral packing order of the damaged skin was significantly reduced in 2-12 μm of skin depth (P < 0.05), deeper than 12 μm was not detected. The skin depth of 0-2 μm could not be determined due to strong interference of SDS. Significant change in the secondary and tertiary structures of keratin was not found.

Visualization of moisturizer effects in stratum corneum in vitro using THz spectroscopic imaging

We use terahertz time-domain spectroscopic (THz-TDS) imaging for the evaluation of moisturizing-substances effects over stratum corneum (SC) samples. Excised SC of porcine skin is used as an in vitro skin model. We evaluate the interaction of SC samples with glycerine and lanolin, two substances commonly used in moisturizers. In order to do this, THz images of SC samples after deposition of the substances are scanned. The response of the SC samples to a commercial moisturizer is also analyzed. Our results show that THz imaging is capable of sensing the distinct interaction mechanisms of the substances with the SC samples. The occlusive nature of lanolin, the hyperosmotic behavior of glycerine, and the moisturizing effect of the commercial moisturizer can be observed using THz-TDS imaging.

Cleansing-induced changes in skin measured by in vivo confocal raman spectroscopy

BACKGROUND

One of the most important steps people can take in reducing the spread of bacteria and viruses is washing the hands with soap and water. Frequent washing, required in certain occupations, can lead to skin dryness, chapping, and itching.

MATERIALS AND METHODS

In vivo confocal Raman spectroscopy was used to study short-term effects of hand washing on product deposition, lipid acyl chain structural disordering, and extraction of important skin components such as natural moisturizing factors, cholesterol, ceramides, amino acids, and changes in skin hydration. Effects of use of either soap, synthetic detergent, or triethanolamine (TEA)-soap/ glycerin were compared at two water temperatures.

RESULTS

Soap use resulted in significant deposition at all depths to 20 μm at 25°C and at the surface and 2 μm at 37°C. Significant decreases were observed in relative amounts of all skin components studied. NMF levels were not changed. Skin dehydration was observed for use of soap at 37°C.

CONCLUSIONS

Short-term effects of frequent hand washing can be monitored with in vivo confocal Raman spectroscopy. Effects of frequent washing may be reduced with lower wash temperature and products. Skin dehydration is not associated with lipid chain disordering.

Microfluidic platforms for modeling biological barriers in the circulatory system

Microfluidic platforms have recently become popular as in vitro models because of their superiority in recapitulating microenvironments compared with conventional in vitro models. By providing various biochemical and biomechanical cues, healthy and diseased models at the organ level can be applied to disease progression and treatment studies. Microfluidic technologies are especially suitable for modeling biological barriers because the flow in the microchannels mimics the blood flow and body fluids at the interfaces of crucial organs, such as lung, intestine, liver, kidney, brain, and skin. These barriers have similar structures and can be studied with similar approaches for the testing of pharmaceutical compounds. Here, we review recent developments in microfluidic platforms for modeling biological barriers in the circulatory system.

A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments

Surfactants form the core of all shampoo formulations, and contribute to a wide range of different benefits, including cleansing, foaming, rheology control, skin mildness and the deposition of benefit agents to the hair and scalp. The purpose of this review was to assist the design of effective, modern, shampoo surfactant technologies. The mechanisms through which surfactants help deliver their effects are presented, along with the appraisal techniques through which surfactant options can be tested and screened for product development. The steps that should be taken to select the most appropriate blend of surfactants are described, and useful information on the most widely used surfactants is provided. The review concludes with an examination of recent developments in 'greener' surfactants, 'sulphate-free' technologies and structured liquid phases for novel sensory properties and for suspending benefit agents.

Surfactant concentration and type affects the removal of Escherichia coli from pig skin during a simulated hand wash

The effect of surfactant type and concentration on a bland soap formulation's ability to remove bacteria from hands remains largely unstudied. Several combinations of surfactants and water were combined to test bacterial removal efficacy using a hand-washing device (two pieces of pig skin and a mechanical motor) to simulate a hand wash. A nalidixic acid-resistant, nonpathogenic strain of Escherichia coli (ATCC 11229) was used. Two anionic surfactants, sodium lauryl sulphate and sodium stearoyl lactylate, and two nonionic surfactants, poloxamer 407 and sorbitan monostearate, each in concentrations of 2, 5 and 10% were studied. A slight positive (r²  = 0·17) but significant (P = 0·03) correlation was observed between hydrophile-lipophile balance value and mean log reduction. No correlation was observed between pH of the treatment solution and the mean log reduction (r²  = 0·05, P = 0·25). A 10% sodium lauryl sulphate mixture showed the highest log reduction (x¯ = 1·1 log CFU reduction, SD = 0·54), and was the only treatment significantly different from washing with water (P = 0·0005). There was a correlation between increasing surfactant concentrations above the critical micelle concentration, and mean microbial reduction (r²  = 0·62, P = 0·001).

SIGNIFICANCE AND IMPACT OF THE STUDY

This study characterizes the role of surfactants in removing microbes during a hand wash. Numerous studies address how surfactants support antimicrobial effect in soap, or cause irritation of skin, but no published studies show which surfactants are best for removing microbes. We used pig skin as a model for human skin and a lathering device to simulate a hand wash. A 10% sodium lauryl sulphate mixture was the only treatment significantly different from a water wash. There was a strong correlation between increasing surfactant concentrations above the critical micelle concentration and mean microbial reduction.