Nanotechnology As A Medicine Essay, Research Paper
Nanotechnology as a Medicine
As modern science learns more and more about the human body and the functions of its various systems, material science is delving into the molecular level. The marriage of these two fields is considered to be nanotechnology. Today s science is working on the design and synthesis of a wide range of nanostructures, with specified geometry and surface characteristics, in hopes of unlocking all the potential uses of nanotechnology. For example, tailored nanomaterials could be used in inclusion chemistry and electrochemistry, material and biomedical sciences, electron microscopy, molecular storage and separation technology. After researching many potential applications of nanotechnology, it is my belief that this new technology is most practical and useful in the medical arena. This essay will give an overview of the nanobot and will illustrate concrete examples of how a nanobot could be used inside the human body.
Nanomachines, ranging from a few to a few hundred nanometers in size, are used to manipulate systems. This manipulation may take place at the cellular level or even the atomic level. A suggested name for these nanomachines is assemblers. Each assembler will be a nanocomputer with a robotic arm. These computers will be programmable with optional instructions for manipulating atoms or molecules. The assemblers will also have the ability to replicate themselves, making production costs relatively cheap.
An example of a naturally occurring assembler is the protein-manufacturing ribosome. Ribosomes manufacture all the proteins that exist in living cells and are relatively small, on the same scale as the suggested assembler. They are capable of building almost any protein. Each ribosome does this by stringing together amino acids in a precise linear sequence. This means that it has some mechanism, such as the suggested robotic arm of the assembler, to grasp a specific RNA molecule and then chemically bond it to a specific amino acid by using a specific enzyme. It also uses this mechanism to manipulate the growing polypeptide, and to cause specific amino acid to react with, and be added to, the end of the polypeptide chain, which ultimately creates the protein. The computer program that the ribosome follows is provided by messenger RNA, a polymer formed from four components: adenine, cytosine, guanine, and uracil. Each specific protein consists of a sequence of several hundred to a few thousand components. The ribosome receives the program from the messenger RNA and acts in a sequential fashion to build the required protein. If technology does not yield small devices to create nanomachines, such as the ribosome, scientists could simply program RNA, and make the ribosome build a biological nanomachine. In fact, scientists have already solved a number of complex problems using RNA computers; it is just a matter of time before they have them manufacturing products. However, since these nanomachines would be made in the human body, it is very likely that they would be restricted to their initial environment. As a result, this method of producing nanobots would only be practical in the biotech field.
In the manufacturing industry, nanomachines, or nanobots, might provide cheap, expendable machinery and labor. The process of manufacturing items would become more precise and efficient. Assemblers would be able to construct items atom by atom or molecule by molecule. They would be given the substances they need and would be able to manufacture the product with little waste or environmental impact. Steel could be constructed without smelting, water could be sanitized without languishing pools of sewage. Even food could be manufactured instead of grown. However, since scientists are closer to producing nanomachines for the human body, than for external environments, it is more realistic to focus on the medical applications of nanotechnology. Topical creams could have nanobots that remove dead or decaying tissue. Solutions could be injected into the body with cancer-cell hunting nanobots, or hormone producing assemblers. Dental hygiene could become as simple as a nanobot-rich oral rinse used like mouth wash.
However, once scientists build nanobots, communicating with them inside the body could be a little tricky; the easiest way to communicate would be acoustically. It is easy enough to get a message in, say with ultrasound, but picking up a message from the nanobot might be a challenge. The nanobot is so small that any acoustic signal it would transmit would be absorbed within a few microns of flesh. However, nanobots could first be instructed to build a large-scale transmitter at a specific location just under the skin, which the doctor could then monitor. The nanobots would have inter-nanobot communication capabilities and would relay messages to the transmitter. In this way, the tasks of the nanobots could be changed in a sequential matter as needed.
The model that is proposed above is not the first model for a nanomachine. In 1996, Dr. Freitas introduced his “respirocyte” nanobot. The respirocyte is a spherical nanobot made of about 18 billion atoms that measures about 1 micron in diameter. These atoms are mostly carbon atoms arranged as diamond, but the structure can be made from sapphire to be nonflammable. The porous structure inside the respirocyte is essentially a tiny pressure tank that can be pumped full of up to 9 billion oxygen and carbon dioxide molecules. Later on, these gases can be released from the tiny tank in a controlled manner. This could be used as artificial respiration to aid those who have varying degrees of respiratory difficulties. Part of the surface of each respirocyte is covered with molecular sorting rotors that can load and unload gases into the nanobot. There are also gas concentration sensors on the outside of each device. When the nanobot passes through the lung capillaries, the onboard computer tells it to release carbon dioxide and pick up oxygen. When the device later finds itself in the oxygen-starved tissues, the computer readings tells the nanobot to reverse the process.
Respirocytes mimic the action of the natural hemoglobin-filled red blood cells whose function is to oxygenate the body. This nanobot is far more efficient than biology, mainly because its diamondoid construction permits a much higher operating pressure. A respirocyte can deliver hundreds of times more oxygen per unit volume than a natural red blood cell. An injection of 2.5 cubic centimeters of respirocytes into the bloodstream can exactly replace the oxygen and carbon dioxide carrying capacity of the patient’s entire blood stream.
As can be seen, producing nanobots for use in medicine seems to be an easier and, thus, more realistic goal than any other nanotechnology, which depends on highly precise, futuristic technology. Furthermore, very simple medical nanodevices can have extremely useful abilities, even when applied in relatively small doses. Other more complex devices will have a broader range of capabilities. Some devices may have mobility, the ability to swim through the blood, or crawl through body tissue or along the walls of arteries. Others will have different shapes, colors, and surface textures, depending on the functions they must perform. They will have different types of robotic manipulators and different sensor arrays. More than just an extension of molecular medicine, nanomedicine will employ molecular machine systems to address medical problems, and will use molecular knowledge to maintain and improve human health at the molecular scale.