You may think this topic is the stuff of science fiction, and it has nothing to do with your life, but it is very likely that you are interacting with nanotechnology on a daily basis without even realizing it.
A nanometer is a millionth of a millimeter in size, and nanoparticles are by definition anything under 100 nanometers in size. For comparison, a red blood cell is 7000 nm and a bacteria is in the neighbourhood of 1000 nm. Nanotechnology involves manufacturing these miniscule particles for various purposes, including industry, household goods, electronics, medicine, food additives, cosmetics and skin products, and as such they have been in the market place for some time without any requirement for labeling and thus without our knowledge. Any nanoparticle under the size of 50nm is so small that it no longer obeys the laws of classical physics, but rather, quantum physics, and can therefore assume optical, electric or magnetic properties. Also, as the particle gets smaller, it has an increasingly large surface area in relation to its mass, which makes it more reactive and less stable, thereby increasing its influence on its environment. With the increased reactivity, it is possible that a harmless substance may become more hazardous to our health.
Nanoparticles can get into the body through inhalation, ingestion, absorption through the skin, and possibly injection in the case of medicines. It is clear that products that are inhaled get into the bloodstream, and therefore have direct access to every part of the body. Because these particles are so small, they even pass the blood-brain barrier and get into the brain. Air-fresheners and other sprays may be a source of nanotechnology in your home that can be inhaled. Nanoparticles that are eaten may come from food additives, drinking water, dust particles that settle on food, toothpaste that is swallowed by accident, teeth fillings that have nanotechnology manufactured into them, for example, and they are absorbed via the “Peyer’s plaques” in the intestine, which is actually part of the immune system. The particles get into the lymph and then the blood, which gives access to the entire body. Some very tiny particles can actually be absorbed directly by the organs themselves. Because nanotechnology is common in cosmetics, skin creams, sunscreens, deodorants, shampoos, and baby products, absorption through the skin needs to be studied more thoroughly. As of now, some suggest that skin absorbed nanoparticles get into the bloodstream and others say they don’t. Hopefully soon the evidence will be more conclusive, as these have the potential to have a big impact especially on babies and small children, who have a large surface area of skin in relation to their body weight. You may want to check the ingredient list of your sunscreens, looking for titanium dioxide or titanium oxide, which is now commonly used in nanoparticle form to better absorb ultraviolet rays. As of now, with skin products it is hard to know whether the benefits out way the risks. Part-way through this article is a list of skin-care products that contain nanotechnology, so you can at least make a choice.
In medicine, nanotechnology in combination with flash-memory technology is being developed to create sensors that can be put into the body to monitor everything like blood pressure, temperature, levels of certain compounds etc. It should be noted that the body is already very good at doing this through hormones, peptides and neurotransmitters for example, but this technology will provide a way for scientists and doctors to see what is happening at microscopic levels, which is intriguing.
I don’t know whether or not nanotechnology is safe. It seems to me that something that can so easily access our cells including our brain tissue has the potential to wreak havoc, and it is likely the effects would be cumulative, so we may not know for a long time whether or not we are being harmed. There are warning signs out there now, just as there was when DDT was first introduced. I would prefer as a consumer to be able to choose products that don’t include nanotechnology, and as in the case of genetically modified foods, would like to see mandatory labeling requirements.
Online at MIT Technology Review Implantable dust-sized sensors to monitor health
Online at Friends of the Earth Nanomaterials, sunscreens and cosmetics: small ingredients, big risks
Online at Nature.com Nanoparticles in sun creams can stress brain cells
Online at MIT Technology Review blogs, David Rotman Small ideas