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Nanotechnology in medicine

Nanotechnology is the science of maneuvering and modifying the structure and properties of matter at an atomic and molecular scale. Due to these manipulations, inert elements start to function as catalyst, and insoluble matter develop unique solubility capacity. Likewise, non-colloids begin exhibiting excellent colloidal properties and electrical non-conductors start conducting electricity. All these materials can be used for a vast variety of purposes in field as diverse as medicine, energy production and electronics.

In recent years, nanotechnology has found innumerable applications in the field of medicine — from drug delivery systems, nanorobots and cell repair machines to imaging, nanoparticles and nanonephrology. Owing to the extensive use of nanomaterials in medical equipments and devices, nanomedicine has become a significant branch of nanotechnology. Here are some important uses of nanotechnology in the field of medicine. All these things prove that nanotechnology will play a significant role in the future, and shows why is nanotechnology useful.

Drug delivery system and nanoparticles
The primary objective of the drug delivery system is to make the life-saving drug available in that part of the body where it is required the most. However, most of the time, these systems fail to work efficiently because the particles of the drug are too large for the cells to absorb, or they are insoluble or they have the potential to cause tissue damage. On the other hand, due to their exceedingly small size, nanoparticles are easily taken up by the cell. Moreover, they are completely soluble and they do not also damage the tissues. In nutshell, the efficiency of the drug delivery system can be increased several times by integrating nanoparticles with them.
Coupling of nanoparticles with biopharmaceuticals
Biopharmaceuticals are peptides or protein molecules that trigger multiple reactions in the human body. They are widely used in the treatment of life-threatening diseases like cancer. The effectiveness of biopharmaceuticals can be increased several times by coupling them with nanoparticles, which will proficiently deliver the peptides or proteins at the tumor site and in this manner cure cancer without causing extensive damage to the adjacent tissues and organs.

Nanotechnology and neuro-electronic devices
Neuro-electronic devices are unique machines based on nanotechnology that connect the nervous system with the computer. These devices not just detect and interpret the signals from the nervous system, but also control and respond to them. They can be used in the treatment of diseases that slowly and steadily decay the nervous system like multiple sclerosis.

Nanonephrology
This is a sub-branch of nanomedicine which is concerned with the detection and treatment of kidney diseases. Here various devices based on nanotechnology are used for the studying the different kidney processes and detecting disorders. Thereafter, nanoparticles and drug delivery system are used for curing the disorder.

Nanotechnology and cell repair machines
These cell repair machines use nanotechnology to penetrate into the cell and rectify disorders like DNA damage or enzyme deficiency. These machines are no bigger than a bacteria or virus.

Nanorobots
The entry of nanorobots will literally revolutionize the world of medicine. These miniature devices would not only be capable of entering into the body and detecting the diseases and infection, but they will also be capable of repairing internal injuries and wounds.

History of nanotechnology

In 1974, Norio Taniguchi of the Tokyo Science University, defined the term nanotechnology for the first time. According to his definition, nanotechnology encompasses separating, processing, consolidating and deforming matter at atomic and molecular scales. Although the term nanotechnology got its definition in 1974, the actual concept was introduced way back in 1867, when James Clerk Maxwell proposed a minuscule entity called Maxwell’s Demon that was capable of handling individual molecules.
Richard Adolf Zsigmondy was the first person to observe and measure the dimensions of nanoparticles. He was also the first person to use nanometer for characterizing the size of the nanoparticles unambiguously. He determined that 1 nm was 1/1,000,000 millimeter. He also developed the first classification system that was based on size of the particle that ranged in nanometer.

In the 20th century several developments took place that helped in characterizing nanomaterials. Like in 1920, Irving Langmuir introduced the concept of monolayer, where a layer of material is just one molecule thick. He received a Nobel Prize for this concept.
In 1959, Richard Feynman, at a meeting of American Physical Society at Caltech, put forth a process that had the ability to control and modify individual atoms and molecules. He stated that by scaling down the dimensions of the atom, dramatic changes can be brought about in its properties. After the discourse, he announced two challenges; first was the construction of nanomotor, which achieved by William McLellan in 1960,and second involved the process of scaling down the letters of Britannica Encyclopedia to fit on the head of a pin; this task was accomplished by Tom Newman in 1985.
In 1965, Gordon Moore made an astounding prediction; he stated that the number of transistors that could fit in a specific area would double every 18 years for the next 10 years. Till this date the trend is continuing, from 2000 transistors in 4004 processors to 7,000,000,000 transistors in Core 2, and Gordon’s prediction is popularly known as Moore’s Law.
In 1974, Dr. Tuomu Suntola et al. patented the atomic layer deposition process. Through this process it became possible to deposit uniformly thin films, one atomic layer at one time. In the 1980s, nanotechnology no longer remained stochastic, but became deterministic. During this period, Dr. K. Eric Drexler advocated the significance of nanomaterials and devices.

So much of groundwork on nanotechnology made the process of production and implementation of nanomaterials relatively simple.

Medical applications of carbon nanotubes

Carbon nanotubes are allotropes of carbon with numerous outstanding properties. In simple words, they are the strongest and stiffest materials known, and thus have many potential applications in various technology/science fields. As for their ideal structure, they can be thought of as hexagonal networks of carbon atoms, rolled up to form seamless cylinders. The bond between the carbon atoms is covalent sp2, which is the reason why they are so strong and stiff. Other than strength, carbon nanotubes have electrical, thermal and many more useful properties. These numerous characteristics make them very desirable in many fields — nanotechnology, electronics, optics, architecture and the medical field.

Combining carbon nanotubes with biological systems can significantly improve medical science — especially diagnostics and disease treatment. Nothing has been fully developed and finalized yet, but we see progress every day.
As an example, we’ll take anti-cancer treatment. When a patient goes through regular chemotherapy, he loses hair and has some other side effects for one reason — because chemotherapy doesn’t destroy “bad” cells only. Along with those tumor cells, it destroys healthy cells too. That’s why scientists are working so hard to avoid that. And carbon nanotubes could make that possible. Scientists from Stanford University have discovered that nanotubes, when exposed to infrared light, tend to heat up to 160°F (70°C) in just 120 seconds. If they are placed inside the cancer cells, they simply destroy them. Testings also showed that infrared has no effects on cell where no nanotubes are placed. This could lead to development of a cancer-killer.
Gene therapy could also be improved by using carbon nanotubes. Let’s say that a damaged or missing gene could be replaced with another one from outside. But that’s complicated — because DNA can’t pass through the cell membrane. What is needed is a transporter, and modified carbon nanotubes play their role here.

Another application of carbon nanotubes in medicine is for sensing the molecules or species. Many studies on the electrochemical reactivity of carbon nanotubes showed that carbon nanotubes can enhance the biomolecules and promote the electron transfer in proteins. It has been found that carbon nanotubes promote electron transfer in heme containing proteins. In heme containing proteins carbon nanotubes are able to access the heme centre of biomolecules that is generally not sensed by the glass electrodes.

Carbon nanotubes can also be used as blood vessels in order to deliver drugs to their target. When the drug delivery is done that way, the drug dosage can be lowered (and it’s cheaper for the pharmaceutical companies). There are two methods, both equally effective — a) the drug can be attached to the side or behind, b) or the drug can actually be placed inside the nanotube.

Carbon nanotubes have many potential applications, but lack of technology for mass production and the costs of the production is what is holding them back. However, considering all the progress they could bring to various fields — especially medicine, we can say that their time is yet to come.

What is DNA nanotechnology

DNA nanotechnology is a nanotechnology division focused on using certain properties of DNA and other nucleic acids to create more complex structures. The DNA is here used more as a structural component rather than a carrier of genetic material.

One of the characteristics of DNA is molecular recognition, and that’s what makes creating DNA complexes possible. DNA is normally a linear molecule, unbranched. Now, it is possible to combine, for example, four individual complementary DNA molecules to create a four-arm complex. Of course, chains have to be complementary to connect (due to Watson-Crick rule – base pairing).

One of the most important junctions that can be made by using this process is DX or double crossover. Here we have two DNA duplexes which share two junction spots, and strands cross from one duplex into another.

There are more types of arrays — one-, two- and three-dimensional. An example of 1D arrays are DNA nanotubes, 2D is present in a process called DNA origami, and DNA polyhedra is 3D.

All the DNA complexes that are made change their properties upon a certain stimulus. There are DNA machines, which are actually machines made from DNA. The most famous one is molecular tweezers. DNA nanotechnology is applied in DNA nanocomputing.