Nanoparticles are one of the latest threats to humankind. Almost. Certainly not in cosmetics. Nanoparticles don’t exist from yesterday, they have been here for quite some time. Only science, that studies them – nanotechnology is relatively new.
What are nanoparticles?
Nanoparticles are small units of material, that is smaller than 100nm. We know that nanometer is 10⁻⁹ right? Nanoparticles can come from a different origin: natural (desert dust), unintentionally produced (burning out biomass and fossil fuel), engineer (sunscreens and other cosmetics, textile).
Why do we even use nanoparticles?
Nanoparticles exhibit new properties and functions of already known materials. This properties are very different than the properties from the same ingredients, but bigger order of size. Not only in cosmetics, but also in food technology and medicine they show a lot of advantages.
- they stabilize and protect ingredients and extend the time of usage (fatty acids in oil, vitamins and antioxidants)
- they affect solubility and speed of solution of the ingredients
- better activity on the skin
- higher effectiveness and tolerance of UV filters
- delivering cosmetic active ingredients in deeper layers of the skin
But everyone says, that nanoparticles are bad,..
Every good invention has a bad side, right? Nanoparticles can be toxic. Toxicity can be a consequence of damaging effects of decomposed products from nanoparticles. Physical properties of nano sized particles (big surface, charge), regardless the chemism of the products that compose nanoparticles, can be a reason for toxicity as well. Nanoparticles show unique physical-chemical properties because of their size. They can be more chemically reactive and can express higher biological activity.
The connection between nanoparticles and unwanted effects
In the last few years the exposure to nanoparticles has risen because of development of different techonologies. Scientists have figured out, that this leads to a lot of unwanted effects on your health system. Connection was made between nanoparticles in the environment and unwanted effects of respiratory tract and cardiovascular system.
Special physical-chemical properties of nanomaterials lead to forming reactive oxygen species in cells. Reactive oxygen species (ROS) cause oxidative stress. Cells react to this kind of stress with inflammation. Research on rodents had shown that empty nanoparticles have a much higher inflammation effect on the unit of mass than bigger particles with the same chemism.
Inhalation of nanoparticles leads to loading in the lungs, they can also enter the bloodstream and brains. That’s why their use is forbidden in aerosols.
Now before you panic, close your computer and throw all of your sunscreens with nanoparticles away
Nanoparticles don’t work like that when applied to the skin. Our epidermis provides effective protection from effects of the environment. They can pass through the cells, hair follicles or sweat glands. But they don’t pass healthy skin. Damaged skin is another story, in this case the particles can pass the skin, but under what conditions remains unknown.
Why are mineral UV filters in sunscreens in nano size?
Mineral filters in their normal size (200-400nm for zinc oxide and 150-300nm for titanium dioxide) disperse really badly and because of that the application is difficult. They reflect and scatter the light and that causes an unwanted white layer on the skin surface. With the help of nanotechnology we are able to reduce the size of the parcticles under 100nm. With doing that we achieve easier application and transparency.
Do nanoparticles cross the skin – main subject of scientists
There are a lot of arguments between scientists whether nano sized particles pass the skin barrier and what are the effects of penetrating into the deeper layers. Some studies prove them passing the skin and their toxic effects on the cells, while others disprove this theory.
There are many differences depending on the sort of the vehicle in which we include nanoparticles. Researches had shown that nanoparticles in mineral oil did not pass the skin, while the ones included in O/W emulsion (oil in water – usual for all the creams) did penetrate. Penetration was much higher in the area with a lot of hairs, which shows the penetration through the pores and hair glands.
The smaller the particles, the bigger the chance that they will penetrate the skin. There is a big difference between a particle that is 2nm big and particle that is 50nm big. As we mentioned before, the smaller the particles, the bigger the chance that their properties will change.
Does a regulative on cosmetic field protect us?
We’ll be honest, not really. Cosmetic producers are not obligated to tell what size of nanoparticles are included in their products. They are obligated to write ‘’NANO’’ next to the filter that is in nano size, but whether this means particles 2nm or 100nm large no one knows, except them.
They represent a big progress in cosmetic industry
Usage of nanometer delivery vehicles is the future. Until now all the cosmetic products contained highly effective ingredients, that manufacturers bragged about. But whether this ingredient will achieve the wanted target in the skin was another thing. Only molecules smaller than 500Da can penetrate in the skin. And if we include a peptide with a molecular mass of 4000Da in our products, it will most certainly not penetrate in the skin. Nano delivery vehicles enable reducing these big molecules into smaller ones, so they can be included to the systems that will reach the target area. This delivery systems are liposomes, dendrimers, solid lipid nanoparticles,..
What is your opinion on nanoparticles in cosmetics?