Engineers uncover biomechanical effects of skin rubbing

Date:
August 28, 2020
Source:
Tohoku University
Summary:
Understanding the skin damage caused by rubbing could lead to
better topical skin treatments and help prevent the formation of
new routes for viral and bacterial infection.



FULL STORY ========================================================================== Understanding the skin damage caused by rubbing could lead to better
topical skin treatments and help prevent the formation of new routes
for viral and bacterial infection.


========================================================================== Tohoku University biomechanical engineers have developed a better
understanding of the damage that can be caused by something rubbing
against the skin. The study was published in the International Journal
of Pharmaceutics. Kenji Kikuchi, who was involved in the study, says
their findings suggest that damaged skin from rubbing face masks and
coverings could potentially provide a route for transdermal virus
infection, however further research would be needed to investigate how
much rubbing is cause for concern.

The uppermost part of the skin, called the stratum corneum, is formed of
layers of keratinocyte cells suspended in a lipid matrix. The stratum
corneum plays an important protective role, forming a barrier against
the invasion of viruses and bacteria, maintaining skin hydration, and
managing skin recovery following damage.

Kikuchi and colleagues at Tohoku University in Japan wanted to develop
a more in depth understanding of the mechanics of skin damage caused by rubbing. This could help scientists develop more effective drugs that
are applied through the skin and to understand how to better prevent
viruses and bacteria from gaining access to the body through damaged skin.

The researchers measured the mechanical effects of rubbing on pig skin,
which is very similar to human skin. A gear rotated against skin samples
at known rates and pressures. The scientists then measured the damage
this caused by exposing the skin samples to a fluorescent dye. The more
damaged the skin, the more the fluorescent dye was able to permeate it.

The team found that the mechanical rubbing caused keratinocytes to
shrink and wrinkle in the direction of the rubbing. Gaps also formed
between the keratinocytes, degrading the skin's barrier function. They
then developed a mathematical formula to describe the permeability of
rubbed skin, which can be estimated from the amount of strain applied.

"We believe our findings could improve transdermal drug delivery and we
plan to investigate the development of novel topical drugs that can be
applied to the skin by rubbing," says Kikuchi.

He adds that their findings could apply to the current pandemic if
rubbing face masks were found by further research to cause skin damage, potentially allowing another avenue for COVID-19 infection. The team did
not specifically investigate this topic and Kikuchi encourages people
to continue to wear face coverings that fit comfortably over the nose
and mouth.


========================================================================== Story Source: Materials provided by Tohoku_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Kenji Kikuchi, Shunsuke Shigeta, Keiko Numayama-Tsuruta, Takuji
Ishikawa.

Vulnerability of the skin barrier to mechanical
rubbing. International Journal of Pharmaceutics, 2020; 587: 119708
DOI: 10.1016/ j.ijpharm.2020.119708 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200828091957.htm

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