TRENDING TECHNOLOGIES
Cleaning the skin: easier said than done
Patrick Gonry – Gobiotics
Hygiene is an important and efficient way to keep the skin healthy and beautiful. Dirt and pathogens that can disturb the proper functioning of the skin are removed on a regular basis. Hygiene is not only crucial to keep the skin
healthy, but also the whole body. Cleaning the skin with shower gels, handwashes and soap bars is a worldwide well-established routine. All these skin cleaning products are based on surfactants. On the other hand, we try to keep our skin
healthy and attractive by supporting its skin barrier. Indeed, an impaired skin barrier leads to redness, dryness, scaling skin and even premature ageing. To support and to protect the skin barrier,
day creams, hand creams and body lotions are used daily. The paradox lies in the fact that the
surfactants that clean the skin to keep the skin healthy are the same ones that destroy the skin barrier. Cleaning the skin in all safety is a challenge. It is even more of a challenge when the skin is dry, damaged or eczematic. In this article, the effect on the skin barrier
of commonly used surfactant is quantified. The skin-supporting effect of a particular rice cleansing rice starch (Remytec® FI) is demonstrated in vivo.
The skin barrier The main purpose of the skin is to protect the body from the aggressive outside world and to keep all the precious molecules inside the skin, such as water. The cell that is building the entire skin barrier is the keratinocyte. Keratinocytes are born at the basal layer,
located at the bottom of the epidermis. At this basal layer, the newborn keratinocytes take the necessary oxygen, water, and nutrients, such as proteins, triglycerides, vitamins, and carbohydrates, from the blood vessels. Once the cell has stocked enough supplies,
it embarks on its epic journey to protect the entire body. When the keratinocyte disconnects from the basal layer it moves up towards the surface of the skin. After the basal layer, the keratinocyte
arrives in the stratum spinosum where it starts to initiate its main task in life: producing skin lipids. These skin lipids are a balanced mixture of ceramides, triglycerides (mainly palmitoleic acid), cholesterol, phospholipids, sphingolipids, squalene, and fatty acids.
www.personalcaremagazine.com When the keratinocyte moves further into
the epidermis towards the surface it arrives in the stratum granulosum where the magic happens. Here, the keratinocytes finish the production of skin lipids and initiate another crucial task for the skin barrier. The keratinocyte starts to make spots (hence the name stratum granulosum) that are called keratohyalin granules. These granules are precursors for filaggrin, an important protein for the proper keratinization of the keratinocytes. The keratinization is necessary to transform the keratinocyte into a hard brick. When the keratinocyte reaches the end of
the stratum granulosum, it becomes very flat and hard like an indestructible brick, which is now called a corneocyte. Simultaneously all the skin lipids produced by the keratinocyte are secreted. They fill the spaces between the brick-like corneocytes, just as mortar holds all the bricks of the wall together.
Natural moisturizing factor Further, the filaggrin produced by the keratinocyte is hydrolyzed into amino acids, forming an important part of the natural moisturizing factor (NMF). NMF is water soluble
and is particularly efficient in entrapping water. When the keratinocytes leave the stratum
granulosum they do not only secrete the skin lipids but also this water-soluble NMF. The water-soluble NMF and the skin lipids are structured in a laminar emulsion which forms a flexible barrier against the environment. The corneocytes, the skin lipids and the
NMF form eventually the stratum corneum. This skin layer acts like a wall, where the bricks are the hard corneocytes and the mortar is the laminar mixture of skin lipids and NMF. This skin layer is the layer that protects the whole body and is therefore life essential. This layer is only a few micrometres thick.
Sebum However, the total skin barrier is not just formed by the stratum corneum. The protective stratum corneum is in turn protected by a kind of human day cream and a microbial day cream. The human day cream is produced by the sebum gland: sebum. It is carefully and constantly secreted over the surface of the stratum corneum. The composition is a mixture of triglycerides, squalene, fatty acids, wax esters and vitamin
May 2024 PERSONAL CARE
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