Do you know how physicochemically sunscreen neutralizes UV rays?

Hello Steemit! This time I want to talk about sunscreens, which are so necessary for skin care today. Perhaps, we have used them in oil, creams or gel, but do you really know which compounds they have and how they work? Well, in this post I will explain how the action of the sun rays on the skin is stopped, by means of this product. I hope you enjoy it.

Ultraviolet radiation

On these days of summer, it is common to use sunscreens. It is the first thing that people, take to the beach to protect themselves from the inclemencies of the sun and thus avoid burns that in time can become something more serious.

Sunscreens

The first thing we need to know is that the sun emits radiations that reach the Earth with the highest energy being ultraviolet (UV) radiation, which can be divided from high to low energy into UV-A, UV-B and UV- C. However, as the Earth's atmosphere absorbs much of this radiation, most of the ultraviolet rays that reach the surface of our planet are of the UV-A type, these rays are responsible for the shrinkage, which is usually not very long-lasting. They have the ability to penetrate to the deepest layers of the dermis, where they generate free radicals that can deteriorate the elastin and collagen of the skin, causing premature aging together with the appearance of wrinkles, stains and lack of elasticity, as well as causing Cancer. In the case of UV-B they reach 1%, penetrate less than UV-A, but they are more reflective, can cause damage to the body by burning tissue and increase the risk of cancer, making them the most dangerous. Finally, UV-C radiation does not reach the earth because it is completely absorbed by the oxygen and ozone in the atmosphere, so there is no danger.

Sunscreens: Physicists and Chemists

All these factors have been taken into account for years by scientists for the manufacture of sunscreens, which use specific compounds that have the ability to filter these rays harmful to our health. How do sunscreens have to be? Well, they are divided into two types, Physicists and Chemists.

Physical sunscreens which are usually composed of titanium and zinc oxides are fluorescent and their particles are deposited on the skin reflecting the radiation. Fluorescence is a phenomenon whereby ultraviolet radiation is absorbed and emitted as radiation of lower energy, in this case the emitted radiation falls within the visible spectrum, reason why these protectors diminish the danger of the radiation. Because of this, generally the protective creams or gels are an intense white color. With these creams, in addition to avoiding erythema, it prevents tanning. The sunscreens that use this type of filter usually indicate in their packaging "total screen effect".

Fluorescence (1) absorption (3) emission

Chemical sunscreens in turn, are composed of substances that are activated by photochemical reactions absorbing ultraviolet radiation by capturing the energy of the sun's rays, and transforming it into thermal energy not harmful to the skin. Mainly, the chemical filters are based on aromatic derivatives that have the pi-conjugate bonding system.

In nature we can find chemical filters such as β-carotene that can be found in carrots. β-carotene is a precursor of vitamin “A” and its antioxidant properties can neutralize the action of free radicals produced by ultraviolet rays. This molecule possesses alternate double bonds in which the electrons can jump between the different pi orbitals absorbing slightly the ultraviolet rays.

β-carotene

Finally, protecting ourselves from the sun's rays is a serious matter, the application of protectors can prevent damage to the skin caused by UV rays. Knowing what sunscreens are made of and how they work can give us an idea of the magnitude of the issue.

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References

Hughes, M. C. B., Williams, G. M., Baker, P., & Green, A. C. (2013). Sunscreen and Prevention of Skin AgingA Randomized Trial. Annals of internal medicine, 158(11), 781-790.

Iannacone, M. R., Hughes, M. C. B., & Green, A. C. (2014). Effects of sunscreen on skin cancer and photoaging. Photodermatology, photoimmunology & photomedicine, 30(2-3), 55-61.

Wondrak, G. T. (2014). Sunscreen-based skin protection against solar insult: molecular mechanisms and opportunities. In Fundamentals of Cancer Prevention (pp. 301-320). Springer Berlin Heidelberg.