Paris: Who hasn't noticed that their skin is tight after showering or bathing?
Even when we use products specifically designed to meet the needs of our skin, this feeling can persist over time – a phenomenon that researchers at Stanford University in the US decided to investigate.
“This work provides a new way for products to influence the physical properties of our skin, which includes not only skin health, but also skin's sensory perception.
"This is an important development. It provides a completely new understanding of how to design such structures," Professor Reinhold Duskart, co-author of the study, said in a statement.
The main obstacle for the body
For the basis of the research, the scientists started from a simple observation: skin is not only the largest body organ by weight and surface area, but it is also the most vulnerable organ to external sources of aggression.
And with good reason: the outer skin layer, the stratum corneum, is the body's main natural defense. One of their functions is to protect them from foreign invaders, such as pollutants, bacteria or chemicals, as well as moisture.
The researchers explained that some procedures, such as the use of antiseptics, cause the stratum corneum to shrink, while others, such as the application of a moisturizing product, cause it to swell.
Taking this into account, the researchers hypothesized that the mechanical forces generated by these skin breakdowns could be converted into nerve signals by reaching special sensory receptors called mechanoreceptors. This alerts the brain and creates a feeling of anxiety.
The researchers tested this concept through in vitro biomechanical testing, numerical modeling, and then a self-review survey published in the journal PNAS Nexus.
Specifically, the aim was to study the effects of nine moisturizing formulas and six cleansing formulas on skin samples taken from the cheeks, forehead and abdomen and to determine changes in the striatum corneum in vitro before incorporating these data into a model. To predict the signals that human skin mechanoreceptors can send.
The final step was to compare it in advance with the stressors of 2,000 women recruited to test humidity in France and 700 women in China to evaluate cleaning workers.
"Can we communicate with human skin?"
We plotted our expectations against what the test takers said and everything stayed in line.
"In other words, we were told exactly what we were told. It was a very impressive relationship, and very high statistical significance," said Reinhold Duskardt.
Some may wonder what the purpose of this discovery is - and besides, in theory, there is nothing we can do to change this method.
However, this research can allow cosmetic laboratories and brands to improve their formulations and develop better products for individual needs.
"[This understanding] provides a framework for developing new products." "say professors from Stanford University.
But that's not all: researchers are looking ahead to plans to develop wearable devices, such as devices that hover above the stroma corneum and deliberately send signals to the brain.
"What we are doing is finding out how mechanical information is transmitted from the stratum corneum to the neurons under the skin layer," Professor Dauskard said.
"Can we now communicate with human skin?" Can we use our understanding of these mechanisms to build a tool to convey non-verbal visual information to a person? This is one area we are very passionate about.