Nanotechnology in the medical field. Alexander Parkes. Paper based on Pathology Lectures Vetsix 2004

Transcription

1 Nanotechnology in the medical field By Alexander Parkes Paper based on Pathology Lectures Vetsix

2 Abstract This paper is about the background of Nanotechnology, the current uses of this technology and then further developments that could arise based on the current uses and research. I have gained the background for this work by attending the pathology lectures at Vetsix 2004 and by using Internet sources for more information. I will be discussing the further developments in Nanotechnology and how they relate to medicine using various sources. Introduction Nanotechnology is the ability to manipulate matter at the atomic scale. This relates to the medical profession for the reason that disease and ill health are caused largely by damage at the molecular and cellular level. Richard Feynman put the idea of Nanotechnology forward in 1959 when he said There s plenty of room at the bottom. In this speech he envisioned technology that would be able to manipulate smaller and smaller units of matter and arrange atoms in the way we want them to be arranged. Then in 1986 Eric Drexler wrote Engines of Creation in which he described nanomachines called assemblers and replicators that would work at the molecular level. The replicators would keep making copies of assemblers that would carry out the useful work. However, there would be no way to stop the replicators from replicating and he stated that the Earth would be covered in grey goo. This is known as the grey goo theory. The most famous discovery was the buckyballs. These are a sixty-carbon crystal that can be used to transport objects into the body and act as protection. Recently Koichi Komatsu and his team from Kyoto University in Japan have found a way to rip open a buckyballs, insert a foreign molecule and stitch it back up again. They have created the ability to lock up atoms and molecules. This process is possible due to the oxidation of a sulphur atom that holds the hole in the buckyballs open, allowing for oxide to float away as a gas. Then after the foreign molecule has been added bonding two carbon-carbon atoms across the centre, and the removal of two oxygen atoms shrinks the hole. Finally the remaining atoms used to keep the hole open are removed and the carbon-carbon bonds are reformed when heated to approximately 340 degrees C. Koichi Komatsu says that this discovery would be useful for building nanoscale electronic circuits. There are many uses for Nanotechnology in the medical field. Since they are small enough to work at the molecular and cellular level they can be used to kill cancer cells. This means that only the cells infected with cancer will be targeted. This is an advantage because if radiation is used to treat the cancer then the healthy cells around the cancerous cell will also be killed. Another application is for providing oxygen. This would provide oxygen if there were circulatory problems or if the circulatory system was impaired. The result of poor circulation is tissue damage because there is a lack of oxygen reaching the tissues. In this method the nanomachines will be used as an artificial red blood cell, carrying extra oxygen which otherwise could not be in the blood and would release the oxygen at places in the body where the concentration of oxygen is low. This machine could also be able to absorb carbon dioxide and release it in the lungs since it would be used in patients with poor circulation. These are some of the uses of Nanotechnology in medicine today. 2

3 Discussion In this section I will discuss some more possible uses of Nanotechnology based on the research and the ways in which it is used today in medicine. Since recent research says Efficient therapy would address the right group of cells at the right time with the right doses. Ideally, a nanoscale device that would be implanted or worn on the skin near the organ in question should contain: sensors that assess the physiological state of the malfunctioning organ; a primitive computer that assesses the correct response; and compartments that release the drug molecules at the right time in the right place. Then it could be possible to do the same, but not just with drugs, but using certain enzymes. For example this idea could help with many genetic diseases. It could help people with Phenylketonuria (PKU). PKU is an absence or deficiency of an enzyme that is responsible for processing the essential amino acid phenylalanine characterizes PKU. With normal enzymatic activity, phenylalanine is converted to another amino acid (tyrosine), which is then utilized by the body. However, when the phenylalanine hydroxylase enzyme is absent or deficient, phenylalanine abnormally accumulates in the blood and is toxic to brain tissue. Also, tyrosine is broken down into melanin, which causes black pigmentation. Using the principle of drug delivery using Nanotechnology I propose that the same principle be used but delve the phenylalanine hydroxylase enzyme instead. This would allow for the phenylalanine to be broken down and this would lower the amount of toxins in the blood, so the brain tissue wouldn t be affected and the person treated would be able to live a normal life and wouldn t have to eat a diet low in phenylalanine. Since the basis of Nanotechnology is to work at the cellular level then it could be used in medicine to prevent lengthy and life threatening operations such as heart bypasses. This is because the nanomachines could be used to destroy the cholesterol cells that are blocking the arteries, and therefore in conjunction with a diet and cholesterol reducing pills could eliminate having to have a heart by-pass. This theory is also based on the uses of it in destroying cancer cells. Also, the new development in buckyballs technology by Koichi Komatsu also brings with it the potential to improve modern technology. For example, with the new ability to lock in atoms and molecules could bring about it the enhancement of MRI scans. This may be possible by locking in an atom or a molecule of a certain metal, which would improve the magnetism and conductivity (i.e. trapped Xeon). This would enhance the images of the MRI scan. One of the uses of the nanobots being researched currently is to be used in conjunction with the body s own immune system to fight disease and viruses. It has been suggested that if you caught a cold or contracted AIDS, you'd just drink a teaspoon of liquid that contained an army of molecule-sized nanobots programmed to enter your body's cells and fight viruses. If a genetic disease ran in your family, you'd ingest nanobots that would burrow into your DNA and repair the defective gene (also, another possible use to treat PKU). Figure 1 (below) shows an artists conception of how the nanobots would work within the blood stream. 3

4 (Figure 1) If they are to be used in conjunction with the immune system then they could be re-programmed to be used as a defense against the body s immune system. This could be used to prevent and stop autoimmune disease such as Rheumatoid Arthritis and Multiple Sclerosis. In Rheumatoid Arthritis the immune system predominantly targets the lining that covers various joints. Inflammation of this lining causes pain, swelling, and stiffness of the joints. Multiple sclerosis is a disease in which the immune system targets nerve tissues of the central nervous system. Most commonly, damage to the central nervous system occurs intermittently, allowing a person to lead a fairly normal life. At the other extreme, the symptoms may become constant, resulting in a progressive disease with possible blindness, paralysis, and premature death. Nanotechnology could prevent this by being present in the areas that are affected by these diseases and fighting off the antibodies that are arriving to kill these areas. This occurs as the body interprets them as being foreign and sends out antibodies to destroy them. This would stop these diseases that cause a lot of pain and suffering. Also, this idea could be used to protect a patient that has just received an organ transplant. Nanotechnology may create some ethic issues, such as some people may believe that if the transplant is being rejected than that is what god wants and to intervene by using very tiny machines would be wrong. Another problem in the use of Nanotechnology is that there is very little public knowledge, or involvement in the rapid growth and the possible dangers of this new technology. Also, there is a lot of resistance to relatively new scientific developments that could be used to benefit mankind such as: genetically modified foods and genetic engineering, so a new technology such as Nanotechnology could create another public uproar. In the future, even weapons as small as a single bullet could pack more computer power than the largest supercomputer in existence today, allowing them to perform real time image analysis of their surroundings and communicate with weapons tracking systems to acquire and navigate to targets with greater precision and control. We ll also be able to build weapons both inexpensively and much more rapidly, at the same time taking full advantage of the remarkable materials properties of diamond. Rapid and inexpensive manufacture of great quantities of stronger more precise weapons guided by massively increased computational power will alter the way we fight wars. Changes of this magnitude could destabilize existing power structures in unpredictable ways. Military applications of Nanotechnology raise a number of concerns that prudence suggests we begin to investigate before, rather than after, we develop this new technology. 4

5 Conclusion With the recent developments in this field of medical research I have come up with a few new possibilities in which this technology can be used in medicine. These new ideas are: to introduce enzymes into the body when a person cannot produce them so that genetic diseases such as PKU can be avoided, to use them to destroy some cells so that lengthy and lifethreatening operations can be avoided, also with the buckyballs and enhancement in MRI scans and finally to use nanomachines to protect against auto-immune disease and to prevent the rejection of organs after transplantation. However, there may be a few problems with my ideas. For example, how can the nanomachines know exactly when to release the enzymes needed, or how can we be sure that the nanobots are fighting off the right antibodies and aren t attacking the transplant itself. These problems will most probably be eradicated as the research into the technology increases. This will eradicate them because as the technology continues then the nano-computers will become more sophisticated and will most probably have a probe to check the surroundings. This would mean that the nanomachines that are responsible for the secretion of the enzyme that is absent in the genetic disease PKU would have a sensor that would be able to detect when the enzyme is low and secrete more. Also, in the protection against autoimmune disease and rejection of transplants the nanobots would have a computer that would be able to detect the antibodies that were coming to destroy the transplant or the area affected by the autoimmune disease and would be able to destroy them, or prevent them from attacking the organ. 5

6 References New Scientist (Jan 2005): Issue number 2483 Vetsix Lecture notes (2004) AS biology Lea, Lowrie McGuigan Uses of Nanotechnology Nanotechnology and Survival Nanotechnology and medicine 6