Nanotechnologies for Medical Applications
In the past, medical treatments have been, rather like medieval architecture, the result of adopting those techniques that worked and discarding those that didn’t. Today, the improved knowledge of how the body functions at the cellular, or ‘nano’, level is leading to many new and better medical techniques. For example, we know that the earlier a disease can be detected, the easier it is to remedy. To achieve this, research is focussing on introducing into the body specially designed nanoparticles, which are composed of tiny fluorescent ‘quantum dots’ that are ‘bound’ to targeting antibodies. These antibodies can bind in turn to diseased cells, and when this happens, the quantum dots fluoresce brightly. This fluorescence can then be picked up by new, specially developed, advanced imaging systems, enabling the accurate pinpointing of a disease even at a very early stage.
Nanotechnology is also leading to faster diagnosis. Diagnosis can be a lengthy and stressful business, often with a test sample having to be sent away for analysis, with the results taking several days or even weeks to arrive. Nanotechnology is enabling much faster and more precise diagnosis, as many tests can be built into a single, often palm-sized device that only requires tiny quantities of sample. This device is sometimes called a ‘lab-on-a-chip’, and samples can be processed and analysed so rapidly that the results can be read out almost instantaneously.
People often complain that the cure for a disease can feel almost as bad as the disease itself, as prescription drugs may have unpleasant (and if we are very unlucky, sometimes even fatal!) side effects. This is because the body needs to be flooded with very high doses of a drug in order to ensure that a sufficient volume reaches the site of the disease. Accurate targeting of the drug can now be achieved, using specially designed drug-carrying nanoparticles. This also means that much smaller quantities of a drug are necessary, so it is less toxic to the body. The drug is then activated only at the disease site (such as a tumour) by light or other means, and the progress of the cure can also be monitored by the imaging techniques described above.
Nano for the Environment
Nanotechnology offers some really exciting breakthroughs in environmentally friendly technologies from extracting renewable energy from the sun to the prevention of pollution. Geoffrey Sacks, the American Economist, in his 2007 BBC Reith lectures entitled ‘Bursting at the Seams’, commented: “The fate of the planet is not a spectator sport”. He continued “ We live in an interconnected world, where all parts of the world are affected by what happens in all other parts”.
There is no doubt that the pressures we are putting on the planet are leading to potentially catastrophic consequences. In the developed world, we have grown accustomed to using our car to go to the local shops, take weekend cruises and even day trips to far-flung places that might have taken three or more months to reach before air travel became commonplace. We like our vegetables and fruit out of season, and increasingly expect to eat meat at least once, if not twice a day. We haven’t thought about the effects of these activities on the planet, which in the past could absorb our excesses, but with the ongoing destruction of the rainforest (which is responsible for 25% of carbon emissions!) and the population of the world reaching over 6.3 billion, the earth is showing signs of being unable to bounce back from the demands we are placing on it.
So what can we do to limit the damage and ensure a future for our children? Firstly, the bad news. The fossil fuel that oils our everyday lives is responsible for 44% of the carbon dioxide we emit annually – and rising! The good news is that the energy from sunlight is sufficient to meet our needs ten thousand times over. Today, more efficient and cheaper solar energy collectors are in the process of being developed using nanotechnology; these could be deployed as small units in our homes. They work particularly well in diffuse light, so would suit even less sunny climates. This would have the benefit of not sterilizing precious land (a diminishing resource for food), and quickly improve the quality of many people’s lives, especially in poorer housing or in the less developed world.
Not only do we need new ways of generating energy, we need better ways of storing it. Nanotechnology is leading to improved, environmentally-friendly batteries and supercapacitors. We also need to reduce damage to the environment. Particularly toxic are those chemicals we use as solvents. Nanotechnology is leading to their eradication through the development new nanocoatings and nano structured surfaces that can effectively repel dirt and other contaminants. Coating metals to prevent corrosion also seriously affects the environment. Many anti-corrosion coatings involve chromium and cadmium, deadly substances, which the EU is seeking to limit. Of course, vehicle and component producers are keen to find alternatives, as recycling of toxic compounds is costly and unpleasant, andnew smart nanocoatings are in the process of being developed that are non-toxic and highly effective. Serious contamination of the environment with heavy metals and other pollutants are thrown into the atmosphere from the fumes and smoke being emitted from industrial processes. It is encouraging to note that most of these of these particles and gases (including carbon dioxide) can be ‘scrubbed’ out - and even reclaimed and reused, using specially functionalised nanomaterials, placed in the waste gas stream. Finally, given the old adage, if you can’t measure it, you can’t control it, fast, accurate, in-situ and online pollution monitoring is essential. New, cheap nanosensors are being developed from techniques used in medicine, that will enable us to do this quickly, effectively and cost effectively.
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