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SPA SCIENCE: Nanotechnology
Nanotechnology means big business to the beauty industry—but are the product formulations safe? Here’s what you need to know to join the conversation.
The number of products using nanotechnology has soared in the past few years, yet consumer knowledge about it has actually decreased. Only 5% of those polled by the Project on Emerging Technology in 2012 claimed to have “heard a lot” about nanotechnology, down from 10% in 2006, when DAYSPA published its first article on the subject (“The Nano Revolution,” February). Although nanotechnology is now being used in everything from electronics to pesticides, many existing products containing nanomaterials serve the biomedical and personal care industries. They range from gold nanoshells that target melanoma tumor cells to nanocrystal eye shadows that lend eyelids a hologram-esque effect.
“In skin care, the most obvious example is sunscreen, which can contain nanoscale titanium dioxide and zinc oxide. There is a great possibility you are already using and selling products with nanoscale ingredients in your day spa,” says Dr. Adam Friedman, vice president of the Nanodermatology Society and director of dermatologic research at the Montefiore - Albert Einstein College of Medicine. “To be more effective, skincare professionals need to educate themselves on this growing product category.”
Nanotechnology is generally defined as the science of working with atoms and molecules at the nanoscale—1 to 100 nanometers (nm). A nanometer is one-billionth of a meter; you would need to stack 100,000 nanometer-size particles to create a film as thick as a piece of paper. Cells and bacteria are measured in micrometers; they can be seen only with the aid of a microscope. A nanometer is smaller, just one-thousandth of a micrometer. Nanoparticles are visible only through very high-power electronic microscopes. The introduction of these instruments in the 1990s led to a cascade of scientific discoveries, especially in biomedicine, where nanoscale functions are common. Ribosomes, for example, which are located within cells, are nanoscale factories that take the raw materials we provide in the form of food and turn them into the proteins needed to form hair, nails and skin.
As with any new area of science, one of the first problems is developing a precise and standardized vocabulary. While most scientists agree that size is the determining factor in nanotechnology, some want different definitions based on whether we are discussing industrial nanotechnology or life sciences.
“In the biomedical field, nanotechnology is not as much about the science of manipulating matter on a nanoparticle level as it is about assembling targeted, biologically active complexes (nanocomplexes) with previously unavailable biological effects and using nanoscale quantities of biologically active substances in a very precise way to imitate or model physiological processes,” says Dr. Michael Danielov, a physician and scientist who trained in the Soviet Union and serves as CEO of New York-based BioNova. The company recently introduced Nano SkinTech, a line of products based on a nanotechnological platform.
Danielov does not believe that simply grinding ingredients like titanium dioxide or zinc oxide into nanoscale particles qualifies as nanotechnology. “Any good quality cosmetic emulsion has always and will always contain nanoscale droplets or particles,” the doctor continues. “For this we do not need new equipment or special claims. Without nanoparticles there is no stable emulsion.” He is lobbying the FDA to adopt a definition of nanotechnology for the life sciences that includes only materials that have some actual effect on human physiology.
Friedman agrees that terminology can be a problem, especially when it comes to describing what are generically called nanoparticles. “Size is not the only factor in nanotechnology. A small fragment of carbon is not nanotechnology, but carbon rolled into a small nanotube designed to conduct electricity or to serve as a cage for a drug is nanotechnology. At the nanoscale, materials can have completely new properties and functions. Fullerenes, for example, are football-shaped, caged molecules of carbon atoms being used in cosmetics to protect and transport active ingredients, and enhance their effect,” he says. (For more on the different types of nanomaterials being used in cosmetics see “Naming Nanomaterials,” below.)
The scientific world is really just dipping its toe into the vast ocean of possibilities presented by nanotechnology, and these definitions will become even more important as the developing field fills its sails. Scientific discoveries in nanotechnology showed extraordinary growth in 2012, according to Friedman. The doctor lists several that should be of particular interest to skincare professionals:
• “Studies showed calcium phosphate and carbonate nanoparticles safely prevented nickel ions from penetrating the skin more effectively than common barrier preparations—a finding that may prove especially valuable to those with nickel allergies or other types of contact dermatitis.
• “A nitric oxide-releasing nanoparticle platform showed antimicrobial activity in animal tests that might be used to effectively treat a broad range of skin and soft tissue infections.
• “Most recently, small interfering RNA (siRNA)-carrying, gold nanoparticles applied to the skin of experimental mice using a commercial moisturizer rapidly penetrated through the stratum corneum and into the epidermis and dermis within just three hours of application. This was the first published investigation demonstrating the ability of nanoparticles to deliver therapeutic payloads deep into the dermis.”
One exciting nanotechnology application is a topical cream containing botulinum toxin, the neurotoxin in Botox Cosmetic (Allergan) now widely used to control facial wrinkles. Two companies are currently conducting clinical trials on similar products. They use nanospheres and absorption enhancers to deliver the toxin into the skin. Early trials are showing good results without damage to the tissue or risk of systemic toxicity. While these topicals will still be drugs available only through physicians, this needleless alternative will undoubtedly appeal to many women. And, who knows, if it proves safe enough, it might someday be applied by estheticians in medical spas.
“These are all exciting applications, provided they are proven to be safe,” cautions chemist John Kulesza, president of Young Pharmaceuticals (youngfarm.com). “No matter the composition, nanoscale particles can exhibit radically different characteristics from standard versions of the same material. This is why products incorporating nanoscale particles must undergo rigorous testing to prove they are safe and effective.”
In April 2012, the U.S. Food and Drug Administration issued two drafts of voluntary guidelines, one for food manufacturers and one for cosmetic manufacturers, to help companies in these industries navigate the introduction of nanomaterials into their products. Legally, cosmetic manufacturers are not required to get premarket approval for any formulation, even those containing nanomaterials. They are legally responsible for the safety of all of their products, however, and all products must be properly labeled. No cosmetic is permitted to make medical claims. The new FDA guidelines ask manufacturers to do additional testing of products with nanoscale ingredients, and they make suggestions for the most effective types of testing. Manufacturers are also encouraged to comment on the guidelines, and their feedback could lead to mandatory regulations in the future.
The Nanodermatology Society issued a response to the guidelines, praising the FDA’s neutral stance and the agency’s ongoing mission to provide better oversight. Other organizations, such as Friends of the Earth and International Center for Technology Assessment, were disappointed that the FDA did not take more stringent action. In a May 2012 news release, these organizations stated that, “existing research raises red flags, indicating that nanomaterials have the ability to enter the bloodstream through contact with the skin, ingestion and inhalation, as well as move in the natural environment once discarded.” These organizations call for greater restrictions on their use.
Scientists at the University of Bath in England released a study in August 2012 (Journal of Controlled Release) that may ease those fears, especially when it comes to the nanoparticles used in sunscreens. They looked at various skin samples treated with sunscreen using confocal microscopy (an advanced optical imaging technique) and found that these nanoparticles do not penetrate the stratum corneum even in small amounts, as some earlier studies had suggested.
This is new technology and there is still much to learn. Many safety issues associated with nanotechnology remain unresolved and, therefore, it’s important that skincare professionals keep up to date and remain aware of nanoscale ingredients in products they use.
In the Marketplace
If there’s a question of safety, why use nanoscale ingredients? We don’t yet know all the answers, but major cosmetic manufacturers are working with nanoscale ingredients and finding some intriguing benefits.
Reportlinker.com, a search engine that offers access to industry, company and country reports, says cosmetics using nanoscale particles surpassed $155.8 million in 2012, with sunscreens accounting for 95% of the market.
“People have to want to use cosmetics, so the look and feel of a product can be just as important as its effects,” says Friedman. “Nanoparticles can play a major role in creating more attractive formulations. Zinc oxide, for example, blocks full-spectrum UV radiation, but at visible particle sizes it leaves an unattractive white film on the skin. Sunscreens with nanoparticles of zinc oxide provide similar UV protection without discoloring the skin.
“Fat-soluble ingredients offer another example,” Friedman continues. “Delivering them to the skin at standard particle sizes means putting them in a heavy, oily cream. Nanoparticles of the same ingredient can be encapsulated and used in lighter, water-based formulations.”
“Nanoparticles have also shown potential in enhancing the efficacy of chemical peels,” adds Kulesza. “An Italian manufacturer uses nanoscale silica gels that basically make the peels much stronger, or at least allow for use of lower levels of acids to accomplish the same effect.”
Nanoscale, highly transparent powders can be used in makeup foundations, eye shadows and lipsticks. They do not visibly coat the skin or change its color; rather, they diffuse light, making wrinkles and fine lines virtually disappear.
For a list of U.S. products using nanotechnology (compiled by the Project on Emerging Technologies), visit nanotechproject.org.
Here are definitions for a few of the nanomaterials currently being tested for or used in cosmetic formulations:
Nanoemulsions are dispersions of nanoscale droplets of one liquid inside another, such as oil and water. Their smaller particle size provides higher stability and better suitability to carry active ingredients; they also increase the shelf life of a product.
Liposomes are bubble-like structures with the ability to carry both water-soluble and -insoluble substances into desired environments. They have been used in cosmetics for decades and have given rise to a whole group of nanomaterials that now include transferosomes, niosomes and ethosomes.
Solid lipid nanoparticles are droplets of lipids that are solid at body temperature. They protect encapsulated ingredients, such as vitamin C and retinol, from degradation, improve penetration and allow for controlled delivery of cosmetic agents over a prolonged period.
Nanocapsules consist of a shell with a space inside that can carry a variety of nanoscale ingredients. The polymer shell can actually decrease penetration, holding active ingredients on the skin’s surface.
Nanocrystals are atom clusters. Typical sizes of these aggregates are between 10 and 400 nm, and they exhibit physical and chemical properties somewhere between that of bulk solids and molecules.
Nanometals act in a variety of ways. Scientists have long known that as nanoparticles of silver oxidize, they produce ions that are deadly to bacteria. Silver nanoparticles are used as antimicrobials in cosmetics, on fabrics and as coatings for personal care items. Nanoparticles of zinc oxide and titanium dioxide are used in sunscreens. Nanoparticles of gold can be used as catalysts.
Buckyballs, or fullerene C60, is perhaps the most iconic nanomaterial. At 1 nm, it has a capacity to behave as a potent scavenger of free radicals and has found its way into some very expensive face creams.
Dendrimers consist of a core, an inner shell, and an outer shell in a symmetrical branching structure. Each portion can have different functionality to control properties such as solubility and thermal stability. They are often used in drug delivery.
Gold nanoshells consist of nanoscale silica particles coated with a thin layer of nanoscale gold. The ability of gold to scatter light at specific frequencies allows gold nanoshells to respond to near-infrared light that can pass through human tissue.
Hydrogels are a network of natural or synthetic polymer chains that swell in water or other fluids without dissolving. High water content gives them flexibility similar to natural tissues, which makes them excellent scaffolds for live cells used in tissue repair. So-called “smart gels” can sense changes in temperature, pH and concentration of metabolite, and release their load based on a specific change.
For more information on the current and future role of nanotechnology, check out any of the following sources:
• Nanodermatology Society (NDS) is a nonprofit, physician-led educational society, but professionals specializing in other areas are also welcome. This reliable source can help you sort nanotechnology fact from fiction.
• Nanowerk (nanowerk.com) is an online portal of original content and resources pertaining to nanotechnology and nano sciences.
• National Nanotechnology Initative is the informational hub for all federal agencies engaged in nanotechnology.
• The Project on Emerging Nanotechnologies is an unbiased collaborative effort to further public and policy dialogue on nanotechnologies.
Linda W. Lewis is an editorial consultant and a regular contributor to DAYSPA.