Lentis/Nanotechnology and Health

Introduction to NanotechnologyEdit

The emerging field of nanotechnology is concerned with the manipulation of matter on the atomic scale. The physical properties of elements and molecules at the nanometer level is a main focus in nanotechnology research. Due to the fact that quantum mechanical effects take hold at the nano scale, nanoparticles sometimes have different properties than their larger counterparts. These properties range from mere color to conductivity and reactivity, and can be used to great effect [1]. One cause of these altered properties is the increased surface area to volume ratio. In bulk materials the ratio of atoms on the surface are often overshadowed by the amount comprising the volume within the material. However, once you cross into the nanometer range this is no longer true [2]. These properties allow for the novel applications of nanoparticles in areas such as agriculture, food packaging, medicine, consumer products, clean water and weaponry.

Because nanotechnology is a relatively new field, many potential benefits and risks have not yet been identified or fully explored. Researchers and experts are working to understand effects that medical applications of nanotechnology and exposure to nanomaterials in every day consumer products may have on human health and the environment [3].

Regulating NanomaterialsEdit

Food and Drug Administration logo

Consumer products containing unregulated nanoparticles could introduce new dangers to human health and the environment. “The public has the right to know whether the products they buy contain nanomaterials and whether the Food and Drug Administration (FDA) has put in place regulations to assure the safety of products containing nanoparticles,” Jaydee Hanson, Policy Director for International Center for Technology Assessment, stated in October 2006 [4].

In December 2008, Consumers Union, publisher of Consumer Reports, tested five sunscreens from manufacturers who claimed that the products did not contain nanoparticles [5]. Results revealed that four of the five sunscreens contained titanium dioxide and/or zinc oxide nanoparticles. In response, Consumers Union submitted a letter to the FDA requesting a “full safety assessment on the use of engineered nanoparticles, particularly in cosmetics, sunscreens, and sunblocks, and to investigate possible enforcement action to ensure accurate labeling as to the presence or absence of nanoparticles” [5].

In June 2011, the FDA published a draft guidance to introduce how the agency will identify whether nanomaterials have been used in FDA-regulated products [6].
Three years later, the FDA issued three more guidance documents, regarding nanotechnology in cosmetics and food [7]. The following year, the FDA issued a guidance for regulating nanomaterials in food for animals [8]. Effective regulation of nanotechnology is crucial for the long-term success of the industry. Currently, public opinion on nanotechnology is not well defined. The general public is not well informed on nanotechnology, and there is a lot of uncertainty around how it is being regulated [9]. The success of the nanotechnology will depend on trusted experts to accurately and effectively convey the risks and benefits of nanotechnology to the public, otherwise nanotechnology may be rejected out of fear [10].

Applications of NanoparticlesEdit


The potential benefits of nanotechnology in the agricultural industry are widespread: more effective and environmentally friendly fertilizer, nanosensors to monitor crop health and soil nutrient levels, and more effective ways to maintain livestock health [11]. These innovations can make agriculture safer, more efficient and lucrative for farmers, as well as more environmentally friendly.

Agrospheres, a startup recently founded by University of Virginia graduates, is working on using nanoparticles to develop an environmentally friendly and safe way to apply and break down pesticides. Their technology provides a safer and more lucrative means of pesticide applications for farmers [12]. Widespread use of such products could provide health benefits by reducing public exposure to toxic pesticides [13].

Some worry that agricultural nanotechnology may develop a stigma similar to genetically modified foods. There is a perception that the general public will shoulder most of the risk, while farmers and food-processors will reap most of the benefits from implementing nanotechnology into agriculture [14]. Effective regulation will determine the extent that nanotechnology influences the agricultural industry [15].

Food PackagingEdit

Nanomaterials have been utilized in many different packaging capacities. Nanocomposites in bottles help minimize carbon dioxide leakage and increase the shelf life of carbonated beverages. Additionally, silver nanoparticles embedded in food storage bins minimize harmful bacteria by killing bacteria from any food preciously stored in the bins [16]. In the future, nanosensors in plastic packaging may help determine when food has gone bad by detecting gases given off by the food and could even change the color of the package material to indicate spoilage. Plastic films with silicate nanoparticles can reduce the flow of oxygen into the package and the leaking of moisture out of the package, helping keep food fresh for longer.

Nanoparticles may also be used in packaging plants in the form of nanosensors to help detect bacteria and other contaminates. While this could greatly reduce the chance of contaminated food reaching the grocery store, the use of nanoparticles in factory plants could also cause harm to factory workers [16]. In 2009, seven Chinese factory workers fell ill and two died from respiratory problems, possibly developed from the use of nanoparticles in the materials being fabricated in their workplace. Ball-like tissue growths and discolored lung fluids of the workers contained particles that were about 30 nm in size. [17]. It is not clear whether the nanoparticles were completely to blame as further studies must be completed to fully understand the effects of nanomaterials on human health. Laboratory tests have shown that nanoparticles can cause damage to rats' lungs, although the factory worker case provides some of the first evidence that respiratory problems caused by inhaling nanoparticles could also occur in humans [17]. This and other similar examples draw discomforting parallels to the case of asbestos, a popular fibrous insulating agent used in houses and buildings until it was later accredited to respiratory problems and mesothelioma.


Nanomedicine is an emerging field in which nanotechnology is utilized for medical and biological purposes. One major research focus is in drug delivery, which involves manipulating nanoparticles to contain and transport drugs or other materials to specific areas of the body. Nanoparticles are ideal for this job because of their inherently small size which allows them to transport drugs through cell membranes and around the body quickly to target specific areas such as cancerous growths or sickly tissues [18].

Some structures have been created to enclose more harmful drugs, such as those used for chemotherapy. These structures open and release their contents only once they have reached their destination and a signal is sent out, unhooking the molecular “latch" [19]. Another possibility being researched is the use of quantum dots, which glow when exposed to UV light [20]. When injected, they seep into cancerous tissues and could act as a guide to surgeons for more accurate tumor removal.

One risk of nanomedicine is the use of toxic particles in some of the transport structures, which could have long term damaging effects on the body. A specific fear lies in the ability of nano particles to penetrate the blood-brain barrier, which could have serious consequences if these particles were left to build up in the brain tissues over time [21]. In response, the field of nanotoxicology has emerged with the intent on studying the toxic properties of some nano scale particles and their possible effects on biological systems [22].

Consumer ProductsEdit

Nanoproducts are considered to be consumer goods that have been enhanced by nanotechnology in some form [23]. Research completed by Friends of the Earth in 2006 demonstrates that nanoparticles are present in personal care products such as sunscreen and cosmetics [24].

Certain brands of sunscreen utilize nano scale zinc oxide and titanium dioxide for their superior abilities to scatter ultraviolet rays. While many sunscreens are opaque white in color, the use of nanoparticles allows for it to be transparent when applied directly to the skin [25]. Many consumers find this property preferable since they do not have to deal with the white residue characteristic of non-nano sunscreens [26]. Cosmetics also utilize nanoparticles for various reasons, including the use of emulsions to contain vitamins in creams, particles in moisturizers to kill bacteria, and improved quality of facial powders [27].
Research shows that these products do not penetrate the deep layers of the skin unless applied over several days and left on the skin for an extended period of time [28]. Even so, open wounds could allow nanoparticles to directly enter the bloodstream and aerosols and powders introduce the possibility of inhalation. Additional dangers include the ability of these specific nanoparticles to produce free radicals and even damage DNA when exposed to certain stimulus, such as UV light [29].

Water FiltrationEdit

In its 2016 Global Risks Report, the World Economic forum portrays a water crisis as one of the most significant potential Global Threats [30]. Lack of access to clean water affects over a billion people and contributes to almost a million deaths each year [31]. Nanotechnology offers a possible solution. Nanoparticles are being used to make affordable, durable and user friendly water filtration devices. A nonprofit organization called PureMadi, has created a tablet that uses silver or copper nanoparticles to disinfect water [32]. While the tablet is not able to filter out sediments that affect the color and flavor of water, it disinfects the water and is so cost-effective, easy to manufacture, and user friendly that it could help provide many with access to safe water [33]. Manipulating nanoparticles of graphene has also been shown to have tremendous benefits in filtering water, especially desalination of saltwater [34]. In addition to desalination, graphene-based nanomaterials have potential environemental applications, and could be used to monitor and remove contaminants from polluted areas [35].


Nations including the US, UK, Russia, Sweden and India are all investing in the application of nanotechnology in national defense. In the US, the Institute for Soldier Nanotechnology is a partnership of the U.S. army, MIT and several private companies. They research and develop nanotechnology to advance soldier protection and survivability [36] [37]. Current research in other industries can be militarized. Nanomaterials offer extraordinary armor protection, nanoparticles can be used as nano-shrapnel more lethal than traditional bombs, and nano-sensors can identify and protect against biological or chemical warfare [38] [39]. Some of the projected applications include micro-combat robots, micro-fusion nuclear weapons, and new chemical agents carried by nanoparticles [40].

During the Gaza War (2008-09) it is alleged that the Israeli Defense Forces used Inert Metal Explosive (dime) bombs in their attacks on the Palestinian fighters [41] [42]. Dime bombs are bombs that encapsulate tungsten particles rather than traditional metal shrapnel. [43]. When they detonate the particles are superheated and burn through all neighboring areas within a small radius. This was the first alleged use of the technology in war, and caused international conversation over nano-weaponry regulation due to the unknown environmental and physical consequences of the nanoparticles.

Currently there is no definitive regulation on nanotechnology in wartime conflict other than in the of Armed Conflict, a general legislation developed in the Conventions following World War II. In 1972 and 1997 weapons conventions prohibited the use of biological and chemical weapons in international warfare. It is conjectured that a convention for nano-weapons will be needed in the coming years.

Social InterfaceEdit

Social groups and their views on nanotechnology

A number of different social groups have shaped the perception and development of nanotechnology over the past fifty years [44]. Each of these actors in the social interface of nanotechnology lie somewhere on a spectrum between realistic and futuristic. Their unique perspectives on issues relating of health and medicine are important for the safe advancement of this emerging field.

In 1959, particle physicist Richard Feynman gave a speech on the direct manipulation of individual atoms which stated, "In the year 2000, when they look back at this age, they will wonder why it was not until the year 1960 that anybody began seriously to move in this direction" [45]. In his speech, Feynman expressed a sense of wonder at the engineering potential of nanotechnology that was shared by other physicists and scientists. This is evident by the numerous nanotechnology applications he considered without any mention of potential health concerns. Today, the National Nanotechnology Initiative (NNI) serves as a central point for all Federal agencies conducting research in nanotechnology. This group also puts the advancement of nanotechnology for commercial and public benefit far higher on its list of goals than the single mention of supporting the responsible development of nanotechnology [46].

Groups considered to be more futuristic have also affected the perception of nanotechnology. As stated in 1993, science fiction author Vernor Vinge believed that "Within thirty years, we will have the technological means to create superhuman intelligence. Shortly after, the human era will be ended" [47]. In writing this essay, Vinge expressed interest in the controversial social implications of nanotechnology. The ideas of futuristic groups have been very influential because they target a broader audience with ideas that are not always founded on science. These futuristic ideas have even helped develop Transhumanism, an international cultural movement that gives its followers hope for eventual immortality. Other religious groups are less hopeful due to beliefs that nanotechnology has the potential to "re-define human nature in ways that are amoral or dangerous" [48]. The ETC Group also acknowledges the profound social and environmental risks of nanotechnology and believes that a moratorium should be placed on research involving molecular self-assembly and self-replication [49]. These concerns are significant concerning the safety of future nanotechnology; however, there are more relevant health concerns on nanotechnology today.

Recently new federally funded groups have emerged with an interest in the ethics of nanotechnology, specifically the Center for Nanotechnology in Society at UCSB and The Center for Nanotechnology in Society at Arizona State University. This has led to the rise of a new social science known as nanoethics. These organizations study the social and ethical implications that nanotechnology has on the world. Nanoethicists study the impact of this emerging technology in a variety of sectors including the economy, environment, medicine, and privacy[50]


As nanotechnology continues to emerge and develop, the social issues centered around the science become more prevalent. Because of the ability of this technology to be extremely small and concealable nanotechnology could eradicate any degree of privacy still constitutionally afforded to citizens [52].


Economically nanotechnology has a multi-faceted impact. The advanced nature of nanotechnology carries a price tag. Research and development is extremely expensive, this has led some experts to question if the technology will be economically available to all class levels and all countries. This question has lead to the development of the “nano-divide” theory. The “nano-divide” Theory states that nanotechnology will further the economic divide between wealthy and developing nations. The industry is expected to be worth 1 billion dollars in the next 10 years. Nanotechnology could cause widespread industry disruption. Proposed uses of nanotechnology such as molecular manufacturing have the potential to completely eradicate entire job sectors and even industries and potentially eliminate the need for global trade [53].


Nanotechnology has extremely promising applications in the field of preventative and regenerative medicine, yet the hefty price tag associated with development of nanotechnology extends into the medical sector. Benefits of the technology are useless if the technology and application is not available to all individuals in need, regardless of economic standing[54].

In addition to economic limitations, nanotechnology in medicine may not be completely safe. Not much is known about the toxicity of the nanomaterials used for drug delivery and imaging. These materials could potentially cause severe health complications. Furthermore, production of nanomaterials has not been studied to an extent where scientists can safely say that generation of nanotechnology does not negatively affect the environment in a way harmful to humans [55].


Nanotechnology is still a new and relatively unknown field with the potential to drastically improve many areas of human life. However, there are still many aspects of this technology that have yet to be researched and whose effects on everything from human health to the environment remain a mystery. The precautionary principle states, “When human activities may lead to morally unacceptable harm that is scientifically plausible but uncertain, actions shall be taken to avoid or diminish that harm”. Ethicists often invoke the precautionary principle when new technology emerges and recently nanoethicists have called for the use of this principle when pursuing development of nanotechnology, they have urged a caution in advance or caution in context of uncertainty. Similar to the case of asbestos, some adverse effects of this technology may take a number of years to surface. We must therefore proceed slowly and provide sufficient research before allowing its widespread use [56].


  1. "Whats so Special about the Nanoscale".https://www.nano.gov/nanotech-101/special Retrieved December 12, 2016.
  2. (2005). "What is nanotech?". http://www.nanocompositech.com/nanotechnology/nanotechnology-overview.htm Retrieved November 14, 2011.
  3. (March 2014) "The unknown risks of Nanotechnology" http://insider.zurich.co.uk/industry-spotlight/unknown-risks-nanotechnology/ Retrieved December 12, 2016
  4. (October 2006). "Groups challenge FDA on nanotechnology risks consumers and environmentalists warn of risks from current uses of unregulated nanomaterials at first-ever agency hearing". http://www.foe.org/news/news-releases/2008-10-groups-challenge-fda-on-nanotechnology-risks-consume Retrieved November 14, 2011.
  5. a b (December 2008). "Consumers union requests FDA safety assessment on use of nanoparticles in cosmetics and sunscreens". http://www.bdlaw.com/news-436.html Retrieved November 14, 2011.
  6. (2011). "Considering whether an FDA-regulated product involves the application of nanotechnology" http://www.fda.gov/RegulatoryInformation/Guidances/ucm257698.htm. Retrieved November 14, 2011.
  7. (2014). "FDA issues guidance to support the responsible development of nanotechnology products" http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm402499.htm. Retrieved December 10, 2016.
  8. (2015). "FDA Issues Guidance on the Use of Nanomaterials in Food for Animals" http://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm457112.htm. Retrieved December 10, 2016.
  9. Corley, Elizabeth A. Kim, Youngjae, Scheufele, Dietram A. (2012) "Public Challenges of Nanotechnology Regulation". https://www.jstor.org/stable/23240008?Search=yes&resultItemClick=true&searchText=regulation&searchText=nanotechnology&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dregulation%2Bnanotechnology%26amp%3Bacc%3Don%26amp%3Bwc%3Don%26amp%3Bfc%3Doff%26amp%3Bgroup%3Dnone&seq=1#page_scan_tab_contents. Retrieved December 12, 2016
  10. Corley, Elizabeth A. Kim, Youngjae, Scheufele, Dietram A. (2012) "Public Challenges of Nanotechnology Regulation". https://www.jstor.org/stable/23240008?Search=yes&resultItemClick=true&searchText=regulation&searchText=nanotechnology&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dregulation%2Bnanotechnology%26amp%3Bacc%3Don%26amp%3Bwc%3Don%26amp%3Bfc%3Doff%26amp%3Bgroup%3Dnone&seq=1#page_scan_tab_contents Retrieved December 12, 2016
  11. Sekhon, B. S. (May 2014). "Nanotechnology in agri-food production: an overview" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4038422/. Retrieved December 4, 2016
  12. http://www.agrospheres.com. Retrieved November 28, 2016.
  13. http://extension.psu.edu/pests/pesticide-education/applicators/fact-sheets/pesticide-safety/potential-health-effects-of-pesticides. Retrieved December 3 2016.
  14. Kuzma, J. VerHage, P. (September 2006) "Nanotechnology in Agriculture and Food Production: Anticipated Applications" http://www.nanotechproject.org/file_download/files/PEN4_AgFood.pdf.
  15. Corley, Elizabeth A. Kim, Youngjae, Scheufele, Dietram A. (2012) "Public Challenges of Nanotechnology Regulation". https://www.jstor.org/stable/23240008?Search=yes&resultItemClick=true&searchText=regulation&searchText=nanotechnology&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dregulation%2Bnanotechnology%26amp%3Bacc%3Don%26amp%3Bwc%3Don%26amp%3Bfc%3Doff%26amp%3Bgroup%3Dnone&seq=1#page_scan_tab_contents Retrieved December 12, 2016
  16. a b (2008). "Nanotechnology in the food industry". http://www.understandingnano.com/column-food.html. Retrieved November 14, 2011.
  17. a b Bond, Allison (August 2009). "Did Chinese factory workers die from inhaling nanoparticles?" http://blogs.discovermagazine.com/80beats/2009/08/19/did-chinese-factory-workers-die-from-inhaling-nanoparticles/. Retrieved November 14, 2011.
  18. (2016) Phillips, Theresa. "Nanomedicine and disease" http://biotech.about.com/od/nanotechnology/a/nanomedicine.htm. Retrieved December 12, 2016.
  19. "Nanotechnology in medicine" http://www.understandingnano.com/medicine.html. Retrieved December 4, 2011.
  20. (April 2011). "Curing quantum dots with ultraviolet light causes a permanent increase in their light emission efficiency." http://www.nanowerk.com/news/newsid=21042.php. Retrieved December 4, 2011.
  21. (October 2007) Bonsor, K. Strickland, J. "Nanotechnology Challenges, Risks and Ethics" http://science.howstuffworks.com/nanotechnology5.htm. Retrieved December 12, 2016.
  22. "Nanotoxicology" http://pubs.acs.org/page/virtual_issue/nanotoxicology. Retrieved December 12, 2016.
  23. "Nanoproduct". http://en.wiktionary.org/wiki/nanoproduct. Retrieved November 14, 2011.
  24. (May 2006). "Nanomaterials, sunscreen and cosmetics: Small ingredients big risks". https://libcloud.s3.amazonaws.com/93/ce/0/633/Nanomaterials_sunscreens_and_cosmetics.pdf. Retrieved November 14, 2011.
  25. Bates, Ramona (June 2010). "Are sunscreens with nanoparticles of zinc oxide safe?" http://www.emaxhealth.com/1024/are-sunscreens-nanoparticles-zinc-oxide-safe.html. Retrieved December 4, 2011.
  26. Rust, Suzanne (August 2011). "Nanoparticles in sunscreen may be unsafe, scientists say" http://californiawatch.org/dailyreport/nanoparticles-sunscreen-may-be-unsafe-scientists-say-11962. Retrieved December 4, 2011.
  27. Sample, Ian (Nov 2008). "Use of nanoparticles in cosmetics questioned" http://www.guardian.co.uk/science/2008/nov/05/cosmetics-beauty-nanoparticles-royal-society. Retrieved December 4, 2011.
  28. (August 2006). "Nanoparticles and sunscreen safety". http://www.nanowerk.com/spotlight/spotid=714.php. Retrieved December 4, 2011.
  29. Saunders, F. (December 2015). "DNA Damage and Nanoparticles" http://www.americanscientist.org/issues/pub/dna-damage-and-nanoparticles. Retrieved December 12, 2016.
  30. (2016). "Global Risks Landscape 2016". http://reports.weforum.org/global-risks-2016/global-risks-landscape-2016/#landscape.
  31. (2015). "Key Facts from the JMP 2015 Report". http://www.who.int/water_sanitation_health/monitoring/jmp-2015-key-facts/en/.
  32. (February 2013). "An innovative nanotech water purification tablet" . http://www.nanowerk.com/news2/newsid=28935.php. Retrieved December 10, 2016.
  33. (February 2013). "PureMadi James Smith". https://www.youtube.com/watch?v=dQBwzmqMNDY. Retrieved December 10 2016.
  34. (July 2012). "A new approach to water desalination". https://www.youtube.com/watch?v=k5Tjy_90WBU. Retrieved December 10, 2016.
  35. Perreault, F. de Faria, A.F. Elimelech, M. (March 2015) "Environmental applications of graphene-based nanomaterials". Chemical Society Reviews 44(16), 5861-5896, doi: 10.1039/C5CS00021A
  36. "Strategic Research Areas" Retrieved December 12, 2016.
  37. Faunce, Nasu. (December 2010). "Nanotechnology and the International Law of Weaponry: Towards International Regulation of Nano-Weapons". Retrieved December 1, 2016.
  38. The NanoAge (n.d.)."Military Uses of Nanotechnology". Retrieved December 12, 2016.
  39. Department of Defense. (December 2009). “Defense Nanotechnology Research and Development Program” Retrieved December 12, 2016.
  40. Bradley, Lucas. (September 2014). "Regulating Weaponized Nanotechnology: How the International Criminal Court Offers a Way Forward". Retrieved December 10, 2016.
  41. Fraunce, Nasu. (December 2010). "Nanotechnology and the International Law of Weaponry: Towards International Regulation of Nano-Weapons" . Retrieved December 1, 2016.
  42. Whitaker, Raymond. (January 2009). "'Tungsten bombs' leave Israel's victims with mystery wounds". Retrieved December 10, 2016.
  43. Global Security (October 2013). "Dense Inert Metal Explosives". Retrieved December 10, 2016.
  44. Schummer, Joachim (2007). "Societal and ethical impacts of nanotechnology." http://scholar.lib.vt.edu/ejournals/SPT/v8n2/schummer.html. Retrieved November 28, 2011.
  45. Feynman, Richard (February 1960). "There's plenty of room at the bottom." Engineering and Science, XXIII, 5, 22-26. http://calteches.library.caltech.edu/47/3/ES.23.5.1960.0.pdf. Retrieved November 28, 2011.
  46. National Nanotechnology Initiative. http://www.nano.gov/about-nni/what/vision-goals. Retrieved November 28, 2011.
  47. Vinge, Vernor (1993). "The coming technological singularity: How to survive in the post-human era." http://www-rohan.sdsu.edu/faculty/vinge/misc/singularity.html. Retrieved November 28, 2011.
  48. Tourney, Chris (November 2011). Nanotechnology and religion. http://www.nanowerk.com/spotlight/spotid=23408.php. Retrieved December 4, 2011.
  49. ETC Group. http://www.etcgroup.org/content/etc-group-has-called-moratorium-environmental-release-or-commercial-use-nanomaterials-ban. Retrieved December 10, 2016.
  50. CNS.UCSB | CENTER FOR NANOTECHNOLOGY IN SOCIETY. (n.d.). Retrieved November 15, 2016, from http://www.cns.ucsb.edu/
  51. CNS-ASU. (n.d.). Retrieved November 15, 2016, from https://cns.asu.edu/
  52. Societal and Ethical Implications of Nanotechnology. (n.d.). Retrieved November 15, 2016, from http://www.nano.wustl.edu/doc/Forms/NRF%20Nano%20Ethics.pdf
  53. Allhoff, F., & P., Lin. (n.d.). Nanoethics.org - The Ethics and Societal Impact of Nanotechnology. Retrieved November 15, 2016, from http://ethics.calpoly.edu/nanoethics/paper010807
  54. Societal and Ethical Implications of Nanotechnology. (n.d.). Retrieved November 15, 2016, from http://www.nano.wustl.edu/doc/Forms/NRF%20Nano%20Ethics.pdf
  55. Nanotechnology. (n.d.). Retrieved November 15, 2016, from https://www.osha.gov/dsg/nanotechnology/nanotech_healtheffects.html
  56. Phoenix, C., & Treder, M. (n.d.). Applying the Precautionary principle to Nanotechnology. Retrieved November 15, 2016, from http://www.crnano.org/precautionary.htm