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UV radiation from the sun is composed of UV-A and UV-B rays. UV-B rays are significantly stronger than UV-A rays and cause sunburns. They damage the outermost skin layer and the DNA in these cells. UV-A rays are weaker, but penetrate deeper into the skin and cause the skin to age faster. Since both types of radiation are considered carcinogenic, it is important to protect the skin when exposed to high levels of light.<\/p>\n
Among other things, nanoparticles are used as filter substances in sunscreen. There are two different types: chemical, and mineral or physical UV filters.<\/p>\n
Chemical filters convert the UV rays on the skin into heat, while mineral filters reflect the sunlight on the skin. Mineral sun creams often use titanium dioxide or zinc oxide particles in the nanometre range. The addition makes the cream easy to spread and – unlike creams with larger zinc oxide particles – it does not form a tough, white layer on the skin.<\/p>\n
However, as the nanoparticles come into direct contact with the skin, there is a certain health risk. In vivo and in vitro studies have shown that zinc oxide nanoparticles can be acutely toxic in the lungs and cell- and genotoxic in human nerve cells.<\/p>\n
For this reason, the particles are coated wafer-thin with silicon dioxide, the main component of sand. The protective coating prevents zinc ions from dissolving from the oxide, which have a toxic effect in high doses. If they are inhaled, for example, they can cause inflammation in the lungs. The nano-shell reduces the genotoxicity of the unprotected zinc oxide particles by a factor of three.<\/p>\n
| \n Important<\/strong><\/p>\n<\/td>\n<\/tr>\n Two different types of UV filters are used in sun creams. Chemical ones convert the radiation into heat, while mineral ones reflect it.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n There are possibilities to use nanoparticles not only on but also in the body. One example is particles in toothpaste.<\/p>\n Minerals are constantly dissolved out of the tooth enamel, which consists of 95% hydroxyapatite (calcium phosphate), and stored again. This is the de- and remineralisation of the tooth. If the environment of the tooth becomes too acidic, for example due to acidic foods such as fruit, the loss of minerals predominates and the enamel partially dissolves.<\/p>\n To counteract the breakdown of enamel, nano-hydroxyapatite is added to some toothpastes.<\/p>\n The synthetic hydroxyapatite is chemically very similar to natural tooth enamel, which is why it combines with it as if it were part of it. Together with proteins from saliva, the hydroxyapatite crystals form the biomaterial. A two to three micrometre solid layer is formed on the tooth, which closes small, damaged areas and protects the underlying tooth material from further attack.<\/p>\n The applied hydroxyapatite behaves in the same way as natural tooth enamel and is worn away and swallowed over time. Hydroxyapatite is considered harmless, and there is currently no evidence of danger or risk for nano-hydroxyapatite, especially since it is not permanently insoluble.<\/p>\n Definition<\/strong><\/p>\n<\/td>\n<\/tr>\n One nanometre is a billionth of a meter. In other words one nanometre is 0.000 000 001 meters.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n De- and Remineralisation<\/strong><\/p>\n In the cosmetics industry, nano-sized colour particles in eyeliners or mascaras guarantee a particularly long shelf life. In most cases, the deep black pigments in eye make-up consist of tiny carbon particles. These are formed during the incomplete combustion of petroleum products, including fluidised catalytic cracker, coal tar, ethylene cracker and some vegetable oils. In cosmetics (especially eye make-up), carbon is used as a pure colourant, which means that it does not need to be mixed with more other substances. Regular carbon black is often toxic, possibly carcinogenic, and also often contains impurities such as arsenic, lead, mercury, sulphur and polycyclic aromatic hydrocarbons, which is why it should be avoided in cosmetic applications.<\/p>\n An example of a certified carbon black pigment is called \u201cBlack 2\u201d, which must meet limits for impurities present. This makes it possible to use the deep black nanopigments in the cosmetics industry.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"_vibebp_attr":"","_vibebp_dimensions":"","_vibebp_responsive_height":"","_vibebp_accordion_ie_support":"","footnotes":""},"module-tag":[],"class_list":["post-1247","unit","type-unit","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/unit\/1247","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/unit"}],"about":[{"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/types\/unit"}],"author":[{"embeddable":true,"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/comments?post=1247"}],"version-history":[{"count":1,"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/unit\/1247\/revisions"}],"predecessor-version":[{"id":1257,"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/unit\/1247\/revisions\/1257"}],"wp:attachment":[{"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/media?parent=1247"}],"wp:term":[{"taxonomy":"module-tag","embeddable":true,"href":"https:\/\/lms.nanoproject.eu\/lms\/wp-json\/wp\/v2\/module-tag?post=1247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}} |
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The process of demineralisation and remineralisation takes place several times a day and describes the breakdown and reconstruction of the tooth enamel. If the degradation is predominant, the teeth lose calcium and cracks form.<\/p>\n