Lentis/Nanotechnology and Health
Introduction to Nanotechnology
The emerging field of nanotechnology is concerned with the manipulation of matter on the atomic scale for research and human use. A main area of research involves rediscovering the physical properties of elements and molecules on the nanometer scale. Due to the fact that quantum mechanical effects take hold at the nano scale, nanoparticles sometimes acquire different properties than their larger counterparts. These varying properties can range from benign characteristics such as color and density, to properties such as conductivity and reactivity which could have more serious effects . One cause of these altered characteristics is due to the increased surface 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 . These properties allow for the novel applications of nanoparticles in areas such as electronics, medicine, optics, magnetism, and computing .
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.
Some say that the rush to commercialize nanomaterial products has outpaced research into their safety . 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 .
In December 2008, Consumers Union, publisher of Consumer Reports, tested five sunscreens from manufacturers who claimed that the products did not contain nanoparticles . 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” .
Applications of Nanoparticles
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 . 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 . 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. . 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 . 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 .
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" . Another possibility being researched is the use of quantum dots, which glow when exposed to UV light . 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 . 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.
Nanoproducts are considered to be consumer goods that have been enhanced by nanotechnology in some form . Research completed by Friends of the Earth in 2006 demonstrates that nanoparticles are present in personal care products such as sunscreen and cosmetics .
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 . Many consumers find this property preferable since they do not have to deal with the white residue characteristic of non-nano sunscreens . 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 .
Current 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 . 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 .
A number of different social groups have shaped the perception and development of nanotechnology over the past fifty years . 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" . 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 .
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" . 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" . 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 . These concerns are important for the safe development of nanotechnology but they are often focused on a distant future while there are already health concerns in nanotechnology today.
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. 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.
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