Small Amounts of Zinc from Zinc Oxide Particles in Sunscreens Applied Outdoors Are Absorbed through Human Skin

Gulson, Brian L.; McCall, Maxine J.; Korsch, Michael; Gómez, Laura; Casey, Philip; Oytam, Yalchin; Taylor, Alan; McCulloch, Malcolm T.; Trotter, Julie; Kinsley, Leslie; Greenoak, Gavin E.

doi:10.1093/toxsci/kfq243

Cited by 289 publications

(260 citation statements)

References 31 publications

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“…[16][17][18] To distinguish Zn in ZnO particles from the body's own Zn, 68 Zn was used to prepare ZnO particles. 19 Two types of particles were used, 19 nm NPs and .100 nm micro-sized particles. After application of sunscreen containing one of these two types of particles on the skin of healthy human volunteers for 5 days, approximately 0.1% of all Zn in the blood was 68 Zn.…”

Section: In Vivo Studies Effects Of Airway Exposure In Experimental Amentioning

confidence: 99%

A review of mammalian toxicity of ZnO nanoparticles

Vandebriel¹,

Jong²

2012

NSA

434

257

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This review summarizes the literature on mammalian toxicity of ZnO nanoparticles (NPs) published between 2009 and 2011. The toxic effects of ZnO NPs are due to the compound's solubility. Whether the increased intracellular [Zn 2+ ] is due to the NPs being taken up by cells or to NP dissolution in medium is still unclear. In vivo airway exposure poses an important hazard. Inhalation or instillation of the NPs results in lung inflammation and systemic toxicity. Reactive oxygen species (ROS) generation likely plays an important role in the inflammatory response. The NPs do not, or only to a minimal extent, cross the skin; this also holds for sunburned skin. Intraperitoneal administration induces neurological effects. The NPs show systemic distribution; target organs are liver, spleen, lung, and kidney and, in some cases, the heart. In vitro exposure of BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells results in cytotoxicity, increased oxidative stress, increased intracellular [Ca 2+ ], decreased mitochondrial membrane potential, and interleukin (IL)-8 production. Decreased contractility of airway smooth muscle cells poses an additional hazard. In contrast to the results for BEAS-2B and A549 cells, in RKO colon carcinoma cells ZnO NPs and not Zn 2+ induce cytotoxicity and mitochondrial dysfunction. Short-term exposure of skin cells results in apoptosis but not in an inflammatory response, while long-term exposure leads to increased ROS generation, decreased mitochondrial activity, and formation of tubular intercellular structures. Macrophages, monocytes, and dendritic cells are affected; exposure results in cytotoxicity, oxidative stress, intracellular Ca 2+ flux, decreased mitochondrial membrane potential, and production of IL-1β and chemokine CXCL9. The NPs are phagocytosed by macrophages and dissolved in lysosomes. In vitro the Comet assay and the cytokinesis-blocked micronucleus assay show genotoxicity, whereas the Ames test does not. This is, however, not confirmed by in vivo genotoxicity assays. Protein binding results in increased stability.

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Section: In Vivo Studies Effects Of Airway Exposure In Experimental Amentioning

confidence: 99%

A review of mammalian toxicity of ZnO nanoparticles

Vandebriel¹,

Jong²

2012

NSA

434

257

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“…From the studies regarding skin exposure to nanoparticles [7,16,109,[117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133] several likely determinants of hazard emerge. These include size, chemical composition, surface characteristics, such as surface coating and surface charge, and crystalline structure.…”

Section: Human Health Hazards Following From Dermal Exposure To Persimentioning

confidence: 99%

Human health hazards of persistent inorganic and carbon nanoparticles

Reijnders

2012

J Mater Sci

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Persistent inorganic and carbon nanoparticles are increasingly engineered for applications and may also be present in conventional materials such as carbon black. Furthermore, they may originate from conventional non particulate materials by processes such as wear and tear. Persistent inorganic and carbon nanoparticles can be hazardous to humans. Relatively much research regards the hazards of inhaled nanoparticles. These may give rise to respiratory disease and to negative effects on other organs, including the cardiovascular system. Determinants of risk of inhaled nanoparticles include: number, size, surface characteristics, shape, structure, and the formation of assemblages. These determinants should preferentially be considered in exposure metrics. A major molecular mechanism underlying the inhalation hazard of nanoparticles is the generation of reactive oxygen species, but other mechanisms such as interactions with proteins and DNA may also contribute. Health hazards may also be linked to ingestion of persistent inorganic and carbon nanoparticles, dermal exposure and exposure of the eye. Standards for workplace exposure to persistent inorganic and carbon are currently emerging and there are options for hazard reduction by elimination and substitution of hazardous nanoparticles and by engineering controls.

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“…Recent studies have demonstrated that small amounts of zinc from ZnO particles in sunscreens applied outdoors are absorbed through human skin. 1 In spite of these concerns, few studies have investigated the effects of ZnO NPs on the internal organs when they were applied to the skin repeatedly.…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers have proposed that there would not be any toxicologic concerns with dermally applied ZnO NPs; 11,12 however, others have demonstrated absorption of ZnO particles through human skin or in a model equivalent to human skin. 1,13 Hence, concerns about ZnO NPs are ongoing, not only with regard to possible skin toxicity, but also systemic toxicity. When ZnO NPs were administered through the oral or inhalational route, damage to the liver was evident.…”

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confidence: 99%

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Zinc oxide nanoparticles: a 90-day repeated-dose dermal toxicity study in rats

Ryu

Seo

Jung

et al. 2014

IJN

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Zinc oxide (ZnO) works as a long-lasting, broad-spectrum physical sunblock, and can prevent skin cancer, sunburn, and photoaging. Nanosized ZnO particles are used often in sunscreens due to consumer preference over larger sizes, which appear opaque when dermally applied. Although the US Food and Drug Administration approved the use of nanoparticles (NPs) in sunscreens in 1999, there are ongoing safety concerns. The aim of this study was to evaluate the subchronic toxicity of ZnO NPs after dermal application according to the Organization for Economic Cooperation and Development Test Guidelines 411 using Good Laboratory Practice. Sprague Dawley rats were randomly divided into eight (one control, one vehicle control, three experimental, and three recovery) groups. Different concentrations of ZnO NPs were dermally applied to the rats in the experimental groups for 90 days. Clinical observations as well as weight and food consumption were measured and recorded daily. Hematology and biochemistry parameters were determined. Gross pathologic and histopathologic examinations were performed on selected tissues from all animals. Analyses of tissue were undertaken to determine target organ tissue distribution. There was no increased mortality in the experimental group. Although there was dose-dependent irritation at the site of application, there were no abnormal findings related to ZnO NPs in other organs. Increased concentrations of ZnO in the liver, small intestine, large intestine, and feces were thought to result from oral ingestion of ZnO NPs via licking. Penetration of ZnO NPs through the skin seemed to be limited via the dermal route. This study demonstrates that there was no observed adverse effect of ZnO NPs up to 1,000 mg/kg body weight when they are applied dermally.

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Small Amounts of Zinc from Zinc Oxide Particles in Sunscreens Applied Outdoors Are Absorbed through Human Skin

Cited by 289 publications

References 31 publications

A review of mammalian toxicity of ZnO nanoparticles

A review of mammalian toxicity of ZnO nanoparticles

Human health hazards of persistent inorganic and carbon nanoparticles

Zinc oxide nanoparticles: a 90-day repeated-dose dermal toxicity study in rats

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