The analysis of scalp irritation by coacervates produced in hair shampoo via FTIR with focal plane array detector, X-ray photoelectron microscopy and HaCaT cells

Modeling lipid layers of atopic skin and observation of changes in lipid layer properties with changes in ceramide content

BACKGROUND

Studies have shown that there is a high correlation between atopic dermatitis and decrease in ceramide content in the lipid bilayer of skin. Moreover, it has been shown that the reduction in ceramide content in the stratum corneum is unique to atopic dermatitis, indicating that there are particular structural differences between the lipid bilayers of normal and atopic skin.

AIM

This study aimed to compare the lipid bilayer of the atopic skin with that of the healthy skin and to establish a structural model of the lipid bilayer for atopy.

METHODS

Molecular dynamics simulations were performed using NAMD 2.8. Models of lipid bilayers of normal skin and atopic skin, and a model of lipid bilayer containing only ceramide were built with CHARMM-GUI. The thickness, area occupied per lipid, and alignment of lipids were compared among the three models. Potential mean force (PMF) of the sodium laureth sulfate (SLES) on lipid bilayers was calculated to predict the affinity between SLES and lipid bilayers.

RESULTS

Potential mean force calculations showed that the lipid bilayer of atopic skin was able to absorb the surfactant more easily than that of normal skin.

CONCLUSIONS

When the ceramide ratio is low, the thickness of lipid bilayer is reduced and its structure is weakened. Other structural differences between the lipid layers of normal and atopic skin included increased area per lipid and poor alignment of lipids. Further, the atopy lipid bilayer model was found to absorb more SLES than the normal skin lipid bilayer model.

Surface science of cosmetic substrates, cleansing actives and formulations

The development of shampoo and cleansing formulations in cosmetics is at a crossroads due to consumer demands for better performing, more natural products and also the strong commitment of cosmetic companies to improve the sustainability of cosmetic products. In order to go beyond traditional formulations, it is of great importance to clearly establish the science behind cleansing technologies and appreciate the specificity of cleansing biological surfaces such as hair and skin. In this review, we present recent advances in our knowledge of the physicochemical properties of the hair surface from both an experimental and a theoretical point of view. We discuss the opportunities and challenges that newer, sustainable formulations bring compared to petroleum-based ingredients. The inevitable evolution towards more bio-based, eco-friendly ingredients and sustainable formulations requires a complete rethink of many well-known physicochemical principles. The pivotal role of digital sciences and modelling in the understanding and conception of new ingredients and formulations is discussed. We describe recent numerical approaches that take into account the specificities of the hair surface in terms of structuration, different methods that study the adsorption of formulation ingredients and finally the success of new data-driven approaches. We conclude with practical examples on current formulation efforts incorporating bio-surfactants, controlling foaming and searching for new rheological properties.

Evaluation of factors triggering sensitive scalp in Korean adult women

BACKGROUND

The scalp care market is growing rapidly and research into the factors associated with sensitive scalp is performed in many countries. However, to the best of our knowledge, no previous study has examined the factors triggering sensitive scalp in Korean women. Thus, the aim of our study was to establish objective standards for sensitive scalp, investigate factors that trigger this condition, and determine the ratio of sensitive scalp in Korean women.

METHODS

A total of 125 Korean adult women participated in the study. The participants answered the questionnaire, had their scalp temperature measured, and the sensitive scalp condition was evaluated and analyzed.

RESULTS

Compared to the non-sensitive scalp (NS) group, the sensitive scalp (SS) group had a significantly higher average temperature and increased heat sensation, dandruff, erythema in the scalp, past history of atopy, history of hair loss, medical history of scalp disease, concern for scalp care, and interest in mild products and frequency of use. The majority of participants in the SS group had a dry scalp, and itching was common.

CONCLUSION

This study may help us to understand the characteristics of the sensitive scalp in Korean females and determine factors associated with triggering a sensitive scalp.