Are products containing nanoparticles a health risk?

Since humans are routinely exposed to a number of materials containing nanoparticles, concerns exist about how such exposure affects human health.

Little is currently known about the long-term effects of exposure to engineered nanoparticles, but cell culture and animal studies have begun to offer clues. Complicating the effort to characterize effects is the number of different nanoparticles and applications, each of which may affect cells.

Data on the cellular effects of nanoparticles come mostly from in vitro cell culture nanotoxicology studies. However, no known studies to date have examined the effects of real-world exposures in humans, i.e., exposure levels that an average human being would experience in day-to-day life. Cell culture and animal studies have used exposure levels that are thought to be far greater than those experienced by an average person. From current research findings, no evidence exists of adverse changes in human health as a result of the use of nanoparticles currently on the market. However, the known adverse health effects of ultrafine particulate matter (dust and pollutants), which is also nanoscale-sized, suggests that the effect of engineered nanoparticles on human health warrants rigorous scientific study.

What is nanotechnology?

Nanotechnology is the understanding and control of matter at dimensions of approximately 1-100 nanometers.  For comparison, a sheet of pater is about 100,000 naonmeters thick and a human hair is about 80,000 nanometers thick and a DNA double helix is about 2.5 naonmeters in diameter.

The science of nanotechnology manipulates matter to create new and unique materials and products. Nanoparticle components are present in materials such as polymers, electronics, paints, batteries, sensors, fuel cells, solar cells, coatings, computers and display systems. Nanoparticles are also found in other consumer products such as, cosmetics and pharmaceuticals.

Commercial Application of Nanotechnology

Over 800 commercial products and applications of nanoparticle-based materials exist. Selected examples are:

  • nanoscale polymer composites that make baseball bats, tennis rackets, motorcycle helmets, automobile bumpers, luggage, and power tool housings more lightweight, stiff, durable, and resilient;
  • surface treatments of fabrics that help to resist wrinkling, staining, and bacterial growth and provide lightweight ballistic energy deflection in personal body armor;
  • nanoscale materials in cosmetic products that provide better coverage and absorption, increase antioxidant and antimicrobial properties, and filter UV light;
  • nanomaterials in computing, communications, and other electronics applications provide faster, smaller, and more portable systems that can manage and store larger amounts of information; and,
  • nanocomposites in food containers minimize carbon dioxide leakage out of carbonated beverages, or reduce oxygen inflow, moisture outflow, or the growth of bacteria to keep food fresh and safe for longer periods of time.

Medical Applications of Nanotechnology

Nanotechnology is being widely applied in many facets of health care. For example, quantum dots (semi-conducting nanocrystals) show unique optical and electronic properties like size-tunable light emission, simultaneous excitation of multiple fluorescence colors, high signal brightness, and long-term photostability. These properties have enhanced both in vitro and in vivo biological imaging, and are being used to image sentinel lymph nodes, tumor-specific receptors, malignant tumor detectors, and tumor immune responses.

In another example, nanoparticle-based hydrogels used as wound dressings have been introduced. Nanoscale inorganic particles have been added to hydrogels as reinforcing agents, improving the strength, elasticity, absorptive capability, and barrier properties of the wound dressing.

Oversight and Regulation of Nanotechnology Products

Existing statutes and responsibility to protect the health of the public provide a foundation for the FDA’s regulation and oversight of nanomaterials. The FDA has not adopted a regulatory definition of “nanomaterial;” instead, it has taken a broadly inclusive approach to considering whether products contain nanomaterials or involve nanotechnology.

In Summary:

Nanotechnology has demonstrated great benefit in the improvement of consumer products and applications. Little is known about how nanomaterials affect human health and the environment, but preliminary research has shown that acute exposure to nanoparticles can affect cellular behavior and may be toxic to some components of the environment. More detailed research is needed to examine how real-world exposure levels affect human health and the environment. In the meantime, regulation of products or applications that include nanomaterials will occur on a case-by-case basis, using science-based methods to evaluate the balance of benefits and risks. AMA policy is strongly supportive of the FDA’s mission to protect the health of the public, and of the EPA’s efforts to ensure that the public is protected from environmental pollution.

Read the full AMA Council on Science and Public Health Report on Nanotechnology and Safety Regulation.

Russell W. H. Kridel, M.D.