Nanotechnology
Variety and diversity of nanotechnologies
Nanotechnology is the general term for a large number of different scientific disciplines that deal with the characterisation and development of materials on the nanometre scale — 1 nanometre is 1 billionth of a metre or 0.000000001 metre. Current applications of nanotechnologies include:
- New materials: ceramics; flame resistant plastics; textiles: ‘stain-free’ and ‘crumple-free’ clothes; coatings: paints, varnishes, self-cleaning windows.
- Food: colorants; ‘intelligent’ packaging indicating if the contents are no longer fit to be consumed or if packaging has been perforated; packaging for strong smelling foods such as cheeses, or food sensitive to oxygen such as meat.
- Communication and information: computer chips and smaller more rapid integrated circuits; high capacity hard disk drives; flash memories.
- Medicine: medical imaging; biocompatible implants and prostheses; drug delivery devices that allow smaller amounts of drugs and better targeting for the treatment of tumours; ‘laboratories-on-a-chip’ that reduce the time for biomedical analyses to only a few seconds; markers to detect disease well before the primary symptoms appear.
- Environmental management: catalytic systems for depolluting diesel engines; tyres that can be recycled; solar panels; combustible batteries; purification plants; means of transport manufactured with nano materials are lighter, carry more payloads, consume less energy and are less polluting for the environment.
- Leisure industry: in tennis rackets, golf balls and bicycles.
- Cosmetics: in sunscreens, skin care and toothpaste.
What is a nanoparticle?
In line with the advisory committee to the European Commission, SCENIHR (Scientific Committee on Emerging & Newly Identified Health Risks), COLIPA defines nanotechnologies as a broad generic term that includes the processes leading to particles satisfying the following criteria1:
The particle is engineered and manufactured intentionally (“man-made”).
The particle is in a form that has three dimensions of the order of 100 nm or less, but greater than 1 nm.
Nanos used in cosmetics
The nanos used in cosmetics differ from nanos used in other industrial sectors in their form and molecular structure, their mode of use and the way they interact with the environment. In essence, they are nanoemulsions and nanopigments.
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| Milk (nanoemulsion) © Unilever |
Nano titanium dioxide cluster (nanopigment) © L'Oréal Recherche |
Nanoemulsions are widespread in nature, such as milk. In cosmetics, they are in fact macroscopic preparations containing oil and water droplets reduced to nanometric size to increase the content of nutritious oils while preserving the transparency and the lightness of the formulas. Sometimes fragile active ingredients, like vitamins, are protected from air inside nanometre-sized bubbles (vesicles) or liposomes that release the ingredient upon contact with the skin at the time of application. Nanoemulsions therefore do not cross the skin barrier. Public health agencies worldwide acknowledge that they are safe2.
Nanopigments such as titanium dioxide (TiO2) and zinc oxide (ZnO) are minerals already present in our natural environment. They are used in sunscreens for their capacity to reflect and scatter UV light thus protecting human skin against adverse effects of UV radiation, including skin cancer3. In sunscreen lotions, nano TiO2 is present in large clusters whose size is much greater than 100 nm to ensure optimal protection of the skin.
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| Nano titanium dioxide clumps from a sun cream on the skin surface © L'Oréal Recherche |
Nano titanium dioxide cluster (nanopigment) © L'Oréal Recherche |
Numerous studies, including those undertaken within the framework of the European Union research programme NANODERM, concluded that nanopigments do not cross the skin barrier, even in cases where the skin is damaged, such as with psoriasis4.
Furthermore, recent studies carried out by the US FDA (Food & Drug Administration) and in Europe, have demonstrated that even in the case where titanium dioxide nanopigments are injected into the blood stream, no adverse effects are observed5.
TiO2, which is an inert material and a reference of non-toxicity, is also largely used in food (colouring agent E171), in consumer goods and in dental/oral hygiene products, like toothpaste.
Nanopigments with proven performance in protecting against skin cancers
Today, one cancer in three is skin cancer. Each year 2 to 3 million skin cancers (carcinoma type) and 130,000 melanomas are diagnosed. The incidence of skin cancer has increased considerably over the last decade. The popularity of outdoor activities, including “sun bathing” is the leading cause of this increase. The reduction of the level of protection from the ozone layer, if continued, will worsen this tendency (World Health Organisation 2007). Many studies show that the use of sun lotion reduces the occurrence and the development of skin and lip cancers, and herpes labial6. Sun lotions protect DNA from damage induced by different types of UV radiation and reduce the development of certain indices of the melanoma7.
Thus, the regular use of sun lotions is essential in the prevention of skin cancer. Products containing zinc oxide or titanium dioxide nanos are more effective than other preparations. Moreover, their transparency facilitates usage and therefore acceptance by consumers and, consequently, improves protection against UVA and UVB8. Today, in many countries around the world, dermatologist associations and national health authorities have set up information campaigns to invite the public to use these products before going out in the sun9.
Proactive safety approach
It should be emphasised that there is no established specific risk for nanotechnology. Size alone is not in itself an indicator of toxicity10.
For consumers
Safety is the number one priority of the Cosmetic Industry. COLIPA can reassure experts and consumers alike that all cosmetic products are subject to rigorous safety testing and evaluation. Products incorporating nanos are no exception to this.
COLIPA members do not market products that could represent a health risk through inhalation. Moreover, COLIPA members do not market products containing carbon nanotubes or fullerenes (aka buckyballs) because the current scientific studies available on possible undesirable effects are incomplete.
For workers
COLIPA members ensure the protection of their personnel at research and production facilities using procedures, like special ventilation and automated systems. On site, the level of exposure to nanoparticles is considerably less than what exists in the home
from cooking.
In Canada, epidemiological studies (1982-1986 & 1995-2001) followed two cohorts of workers in order to evaluate the possible health effects of workplace exposure to nanopigments. Both studies concluded that no undesirable health impact resulted from working with these materials11.
For environmental protection
Recent studies concluded that titanium dioxide and zinc oxide nanopigments are not ecotoxic and therefore do not harm the environment12.
While reliable methods are currently practiced to test the safety of the nanomaterials used in cosmetics, COLIPA members are working towards the development, optimisation and validation of new alternative methods to further improve the current regulatory tests for environmental impact.
COLIPA supports the work for an international consensus on standards
The current lack of clarity in the terminology used around nanotechnologies (nomenclature) can lead to misunderstandings and trigger doubts about
this issue.
There is a need for common definitions, standards and norms for nanotechnologies that are relevant and adapted to the various industrial sectors in order to avoid the excessive and sometimes inappropriate use of the prefix nano that can penalise innovation. COLIPA supports the work of ISO, OECD and the SCENIHR on this subject.
COLIPA welcomes debate based on sound science
It is of paramount importance to base discussion around any innovation, like nanotechnology, on reliable scientific studies13. COLIPA is engaged in an open exchange of views on nanotechnology. In this context, COLIPA welcomes the initiative to develop a European Code for Responsible Nanotechnologies.
1 SCENIHR, Opinion on the scientific aspects of the existing and proposed definitions relating to products of nanoscience and nano technologies. Brussels, November 2007.
2 Imbert D and Wickett R: Topical delivery with liposomes.
Cosmetics and Toiletries magazine. 1995; 111:32-45.
Honeywell-Nguyen P et al.: Quantitative assessment of the transport of elastic and rigid vesicle components and a model drug from these vesicle formulations into human skin in vivo. J. Invest. Derm. 2004; 123(5):902-10.
Van den Bergh B et al.: Interactions of elastic and rigid vesicles with human skin in vitro: electron microscopy and two photon excitation microscopy. Biochim. Biophys. Acta. 1999; 1461:155-173.
US FDA, Nanotechnology Report 200 www.fda.gov/nanotechnology/ taskforce; British Standards Institute, PAS 130:2007, Guidance on the labelling of manufactured nanoparticles and products containing manufactured nanoparticles.
3 IARC Handbooks of Cancer Prevention: Sunscreens. World Health Organization, Lyon 2001.
Lademann J, et al.: Penetration of TiO2 microparticles in a sun screen formulation into the horny layer and the follicular orifice. Skin Pharmacol. Appl. Skin Physiol. 1999, 12: 247-256.
Dussert A, et al.: Characterization of the mineral content of a physical sunscreen and its distribution onto human stratum corneum. Int. J. Cosm. Sci.. 1997, 19: 119-129.
Pflucker F, et al.: The outermost stratum corneum layer is an effective barrier against dermal uptake of topically applied micronized titanium dioxide. Int. J. Cosm. Sci. 1999, 21: 399-411.
Gamer A, et al.: The in vitro absorption of microfine ZnO and TiO2 through porcine skin. Toxicology in Vitro. 20, 301-307, 2006.
Roberts M.: Nanoparticles In Topical Products – A Consumer Health Risk? FDA Public Meeting on Nanotechnology, 10 Oct. 2006.
Nohynek G, et al.: Grey goo on the skin? Nanotechnology, cosmetic and Sunscreen Safety. Crit. Rev. Tox. 2007, 37:1-27.
Nohynek G, et al.: Nanotechnology, Cosmetics and the Skin: Is There a Health Risk? Skin Pharmacol. Physiol. 2008 in press.
Mavon A, et al.: In vitro Percutaneous Absorption and in vivo Stratum Corneum Distribution of an Organic and a Mineral Sunscreen. Skin Pharmacol. Physiol. 2007, 20:10-20.
Stern S, et al: see note 1.
4 Butz T, et al.: No evidence for nanoparticle penetration into living skin. Preliminary data presented at ECETOC,Barcelona, 2005.
Pinheiro T, et al.: The influence of corneocyte structure on the interpretation of permeation profiles of nanoparticles across skin. Nucl. Instru. and Meth. in Phy. Res. B 2007, 260:119–123.
Borbala K, et al.: Investigation of micronized TiO2 penetration in human skin xenografts and its effect on cellular functions of human skin-derived cells. Exp. Derm. 2008.doi:10.1111/j.1600-0625.2007. 00683.x
Filipe P, et al: Nanotoxicity of TiO2 and ZnO containing sunscreens versus the stratum corneum barrier dogma. Expt.Tox. 2008 in press.
Sugibayashi K, et al.: Safety evaluation of TiO2 nanoparticles by their absorption and elimination profiles. J. Tox. Sci. 2008 in press.
5 Umbreit T, et al.: toxicology of TiO2 nanoparticles: Characterization and tissue distribution in subcutaneously and intravenously injected mice. Presented at the US Society of Toxicology meeting, Abstract n° 1386, Charlotte, 2007.
Fabian E, et al: Tissue distribution and toxicity of IV administered TiO2 nanoparticles in rats. Arch. Tox. DOI 10.1007/s00204-007-0253-y
6 Pogoda J, et al.: Solar radiation, lip protection, and lip cancer risk in LA County women (Ca). Cancer Causes Control 1996, 7(4): 458-463.
Rooney J, al.: Prevention of ultraviolet-light-induced herpes labialis by sunscreen. Lancet 1991, 338(8780): 1419-1422.
Nohynek G, Schaefer H.: Benefit and risk of organic ultraviolet filters. Regul. Toxicol. Pharmacol. 2001, 33: 285-291.
7 Young A, et al.: Protection by UVA and UVB sunscreens against in situ dipyrimidine photolesions in human epidermis is comparable to protection against sunburn. J. Invest. Dermatol. 2000, 115: 37-41.
Gallagher R, et al.: Broad-spectrum sunscreen use and the development of new nevi in white children. A randomized controlled trial. JAMA 2000, 283: 2955-60.
Gallagher R.: Sunscreens in melanoma and skin cancer prevention. CMAJ 2005, 173(3): 244-245.
Mahroos M, et al.: Effect of sunscreen application on UV-induced thymine dimmers. Arch. Dermatol. 2002, 138(11): 1480-1485.
Lee T, et al.: Site-specific protective effect of broad-spectrum sunscreen on nevus development among white schoolchildren in a randomized trial. J. Am. Acad. Dermatol. 2005, 52: 786-792.
8 Delrieu P, et al.: Perspectives on Supplying Attenuation Grades of TiO2 and ZnO for Sunscreen Applications FDA Meeting on Nano technology, 10 Oct. 2006, Washington DC. www.koboproducts.com
9 www.cancer.org.au/content.cfm?randid=906824 and www.cancer.org/docroot/PED/content/ped71Skin_Cancer_Detection_What_You_Can_Do.asp
10 Stern S, et al: Nanotechnology safety concerns revisited. Tox. Sci. 2008, 101:4-21.
11 Ramanakumar A, et al.: Risk of lung cancer following exposure to carbon black, titanium dioxide and talc: Results from two case-control studies in Montréal. Int. J. Cancer 2008, 122:183-189.
12 Margit Heinlaan M, et al.: Toxicity of nanosized and bulk ZnO, CuO and TiO2 to bacteria Vibrio fischeri and crustaceans –– Daphnia magna and Thamnocephalus platyurus. Chemosphere, 2008, doi: 10.1016/j. chemosphere.2007.11.047.
Federici G, et al.: Toxicity of TiO2 nanoparticles to rainbow trout (Oncorhynchus mykiss): Gill injury, oxidative stress, and other physiological effects. Aquatic Tox. 2007, 84: 415–430.
13 Berube D. Rhetorical gamesmanship in the nano debates over sunscreens and nanoparticles.
J. Nanopart. Res. 2008 in press.