Grey Gooon the Skin? Nanotechnology, Cosmetic and Sunscreen Safety

Abstract

Many modern cosmetic or sunscreen products contain nano-sized components. Nanoemulsions are transparent and have unique tactile and texture properties; nanocapsule, nanosome, noisome, or liposome formulations contain small vesicles (range: 50 to 5000 nm) consisting of traditional cosmetic materials that protect light-or oxygen-sensitive cosmetic ingredients. Transdermal delivery and cosmetic research suggests that vesicle materials may penetrate the stratum corneum (SC) of the human skin, but not into living skin. Depending on the physical/chemical properties of the ingredient and the formulation, nano-sized formulations may enhance or reduce skin penetration, albeit at a limited rate. Modern sunscreens contain insoluble titanium dioxide (TiO(2)) or zinc oxide (ZnO) nanoparticles (NP), which are colorless and reflect/scatter ultraviolet (UV) more efficiently than larger particles. Most available theoretical and experimental evidence suggests that insoluble NP do not penetrate into or through normal as well as compromised human skin. Oral and topical toxicity data suggest that TiO(2) and ZnO NP have low systemic toxicity and are well tolerated on the skin. In vitro cytotoxicity, genotoxicity, and photogenotoxicity studies on TiO(2) or other insoluble NP reporting uptake by cells, oxidative cell damage, or genotoxicity should be interpreted with caution, since such toxicities may be secondary to phagocytosis of mammalian cells exposed to high concentrations of insoluble particles. Caution needs to be exercised concerning topical exposure to other NP that either have characteristics enabling some skin penetration and/or have inherently toxic constituents. Studies on wear debris particles from surgical implants and other toxicity studies on insoluble particles support the traditional toxicology view that the hazard of small particles is mainly defined by the intrinsic toxicity of particles, as distinct from their particle size. There is little evidence supporting the principle that smaller particles have greater effects on the skin or other tissues or produce novel toxicities relative to micro-sized materials. Overall, the current weight of evidence suggests that nano-materials such as nano-sized vesicles or TiO(2) and ZnO nanoparticles currently used in cosmetic preparations or sunscreens pose no risk to human skin or human health, although other NP may have properties that warrant safety evaluation on a case-by-case basis before human use.

The potential health risk of titania nanoparticles

“…Skin hair follicles are surrounded by a tight network of capillaries (Fig. 4), which facilitates transdermal drug delivery [49] but also provides a possible route for NP entry and a long-term NP reservoir. Although only 1% of applied TNPs were found in the orifices of hair follicles, these deposits were much harder to remove than those on the skin surface [45][46][47][48].…”

“…So far, there is no evidence that NP skin penetration leads to systemic exposure. Most studies have found that TNPs remain at the outmost layer of stratum corneum, possibly in skin furrows or the infundibulum; little TNP has been found in the living epidermis [49,[51][52][53][54][55][56]. Moreover, acute dermal irritation studies and local lymph node assays in mice found no irritation or sensitization [57].…”

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

“…Furthermore, ZnO as a bio safe compound is found to be useful in applications linked to human life, such as in cosmetic, medical, and dental products [1,2]. It has become one of the most promising compounds that can be employed in advance technology applications, and it demonstrates outstanding performance in various application fields, such as sensors for different analytics including those for hydrogen, oxygen, Volatile organic compounds (VOCs) [3][4][5], urea, cholesterol, and glucose [6][7][8][9].…”

Toxicity assessment on haemotology, biochemical and histopathological alterations of silver nanoparticles-exposed freshwater fish Labeo rohita

“…It also deals with the quantitative evaluation of severity and frequency of nanotoxic effects in relation to the exposure of the organisms. Metal nanoparticles have been used in various fields such as consumer products, industrial applications and health care technology are likely to enter the environment (Masciangioli and Zhang 2003;Nohynek et al 2007;Benn and Westerhoff 2008) stated that the AgNPs are commonly used in the textiles and these nanoparticles might be released into the environment. The toxicological evidence of AgNPs is still lacking and the safety measurements for these nanoparticles have to be framed.…”