Is a cream with nanoparticles nothing more than a publicity stunt?

Nanoparticles do not penetrate into the deep layers of the skin

Nanonews Network based on University of Bath materials: New study says nanoparticles don't penetrate the skinThe results of a study conducted by scientists at the University of Bath (UK) challenge the claim that nanoparticles included in therapeutic and cosmetic creams are able to deliver their active ingredients to the deep layers of the skin.

Nanoparticles – tiny particles smaller than one hundredth of the thickness of a human hair – are used in sunscreens and some cosmetic and therapeutic creams. British scientists have found that even the smallest nanoparticles do not penetrate through the epidermis into the deep layers of the skin. These data are important both for pharmacologists and for cosmetic companies developing creams with nanoparticles, which are supposed to transport their ingredients into the deep layers of the skin.

On the other hand, they dispel concerns about the potential absorption of harmful nanoparticles, for example, from sunscreens, into the bloodstream. The researchers used laser scanning confocal microscopy to answer the question whether polystyrene balls with fluorescent labels ranging in size from 20 to 200 nanometers can be absorbed by the skin. They concluded that even with partial damage to the skin sample (removal of the upper layers with a Band-Aid), nanoparticles do not penetrate through the upper layer of the epidermis, known as the cornea.

"Previous studies on the penetration of nanoparticles into the skin have led to contradictory conclusions," comments Professor Richard Guy, who led the work, on the results. "The use of confocal microscopy allowed us to unambiguously visualize and objectively assess what happens to nanoparticles on an uneven skin surface. While previous studies have shown that nanoparticles appear to penetrate the skin, our results suggest that in fact they may simply be deposited in the deep folds of the skin sample. The role of the skin is to function as a barrier to potentially hazardous chemicals and to reduce water loss. Our research shows that the skin does its job well. Thus, although an unsuspecting consumer may believe that the nanoparticles in his creams "carry" the active ingredient into the deep layers of the skin, we have shown that this is clearly not the case."

There is also a spoonful of positivity in the results of the work of the work: the authors suggest that it is possible to develop a new type of nanoparticle-based skin preparations with a long-term and controlled release of the drug contained in them. This will allow to achieve prolonged delivery of active ingredients and reduce the necessary frequency of application of drugs to the skin.

Figure from the article Objective assessment of nanoparticle disposition in mammalian skin after topical exposure, published in the Journal of Controlled Release:

Cross-sections of the upper layers of pig skin (confocal microscopy) 5 minutes after applying glowing green nanoparticles of 200 (a, b), 100 (c, d) and 20 nm (e, f) and just water (blue – g, h). In the pictures a, c, e and g – intact skin, on b, d, f and h – skin from which a Band-Aid has just been torn off. The horizontal red line in some images is a reflection from the cover glass when the illumination intensity increases – VM.

Portal "Eternal youth" http://vechnayamolodost.ru10.10.2012