Essentially, nanotechnology involves the study and use of nanoparticles, which range between 1 and 100 nanometers in size.
These structures range in scale depending on the type of atoms and molecules to submicron dimensions. Here, it is worth noting that nanoparticles are made up of clusters of atoms/molecules. This makes them larger in size compared to individual atoms. However, they are still much smaller compared to micro-organisms or fine particles.
For instance, a nanoparticle is composed of a few hundred atoms. Compared to cells and other micro-organisms (single-celled) nanostructures are too small to be viewed using ordinary microscopes. For this reason, very advanced, high power microscopes have to be used.
Manipulation of these structures has allowed the technology to be used in various industries to produce different types of products for various applications.
* The length of a typical bacterium is about 200 nanometers while an atom is about 1 nanometer.
By manipulating nanoparticles, and thus the atoms they are composed of, it's possible for scientists to produce a variety of nanotechnology products for different applications. However, nanoparticles and atoms/molecules are very small, and thus difficult to work with given that they cannot be seen with the naked eye.
In order to overcome these difficulties, scientists have had to find ways through which they can design and engineer materials down to the atom or atom cluster level. In this case, atoms and molecules are arranged in a manner that allow for the creation of new materials and structures. Since this involves working at the nano level, the technology has come to be known as nanotechnology.
* By arranging given atoms differently, properties of matter are changed. For instance, while coal and diamonds are made of the same type of atoms (carbon atoms) they have different properties where diamonds are harder compared to coal.
There are different types of nanoparticles used for different purposes. Applications of different nanoparticles depend on their properties.
The following are some of the major types of nanoparticles:
Molecular Base and Structures
There are two types of molecular base nanoparticles including the organic and non-organic. The organic type of nanoparticles contains carbon and includes nanotubes and buckyballs. These types of nanoparticles are commonly referred to as fullerenes. As such, they exist in structures that look like balls or tubes.
Inorganic nanoparticles include the noble and magnetic metal as well as semi-conductors. Here, the magnetic type including cobalt, iron and nickel can be easily manipulated using a magnetic field while Noble metals such as copper, silver and platinum tend to be versatile agents that are commonly used for various biomedical applications. Lastly, semiconductors such as zinc oxide are produced chemically and also used for various industrial and biological applications.
Structures - Based on structure, nanoparticles are divided into three groups, these include:
There are a number of methods that are used for the purposes of synthesizing nanoparticles so as to have control over their size, structure, quality and purity among others. The method used is often to determine the state of the end product. However, depending on the intended outcome, scientists use the following methods:
Some of the other methods used for nanoparticle synthesis include:
Templating – This is the synthesis process that used morphological properties with reactive deposition/dissolution.
Combustion - The process that used rapid heating of a solution that contains redox groups
Gas phase methods - This is either done physically or mechanically
Nanostructures are produced from nanoparticles, which are in turn used to make non-material.
The following methods are used for synthesis of nanostructures:
The top-down method is also referred to as miniaturization. Here, such physical processes as crushing and grinding are used to break down large particles. Here, physical force is also used for the purposes of combining smaller units into a larger unit of the material. This method has the advantage of imperfections of the structure due to the physical force used.
Unlike top-down, bottom-up typically involves building the structure from bottom up. This is done using atoms, molecules or clusters. In this case therefore, synthesis is done atom by atom until the structure is complete. Given that there is sufficient control, scientists are able to control size and shape in order to produce given structures/material as required.
While research studies are still being conducted
to improve and perfect nanotechnology for medical use, several advancements
have allowed the technology to be used in healthcare. One of the most recent
examples of this is the use of gold nanoparticles as probes.
Today, gold nanoparticles are being used for the purposes of detecting nucleic sequences. In addition, the technology has also been shown to have the potential of helping in cancer treatment.
The technology has also been shown to have the potential to not only diagnose, but also treat atherosclerosis. Here, scientists have already managed to create a nanoparticle that is similar to HDL (high-density lipoprotein) used to reduce the size of plaque in arteries. This can greatly help patients with high blood pressure.
Currently, more studies are being directed towards the use of nanotechnology for regenerative medicine. These studies aim to improve nanotechnology in medicine for bone and tissue engineering. This will allow scientists to grow complex tissues for organ transplant as well as use the technology to repair spinal cord injuries. In doing so, the technology will help treat numerous conditions that continue to affect many patients today.
With the ever increasing energy demands,
nanotechnology has been shown to significantly contribute to the production of
alternative energy. Many scientists are optimistic that nanotechnology will
allow for the production of affordable, clean and renewable energy, which will
help deal with the current environmental issues.
One of the areas that nanotechnology is currently being used is towards improving the production of fuel from raw petroleum materials. Through improved catalysis, it has become possible to reduce the amount of fuel consumed in addition to enhancing combustion while decreasing friction. This helps control pollution thereby benefiting the environment.
In addition, the technology is being used to produce carbon nanotube wires that will significantly reduce resistance thereby reducing power loss during transmissions.
With regards to clean and renewable energy, nanotechnology is being used in solar panels where it helps in the conversion of sunlight (energy from the sun) to electricity. With advancements in the technology, it is expected to better and affordable power in the near future.
In addition to solar panels, nanotechnology is also being used to produce batteries that not only charge quickly, but are also lighter and more efficient.
Some of the other areas in which the technology is being used for better energy include:
In tennis, nanotechnology has been used to
design tennis racquets that are more stable and powerful. This has been
achieved by adding nanotubes to the racquet frames thereby enhancing their
strength. This has been found to help players gain better control of the
racquets when it comes in contact with the ball.
In addition to the racquets, scientists are also working to improve the balls used in tennis and have them bouncing longer. The technology will see butyl rubber being combined with clay particles.
Apart from the sport of tennis, nanotechnology is also being used in the following sports:
In transportation, recent research studies are
being directed towards the production of lighter, smarter and more efficient
means of transport (vehicle, spacecraft and ships etc). By using
nanotechnology, scientists are optimistic that they will be able to develop
better and more efficient products such as polymer nanocomposite parts, better
batteries and tires among others.
These are aimed at enhancing efficiency and safety. In addition, scientists are working on nanoscale sensors among other devices that will improve safety.
As for the environment, nanotechnology presents the following benefits:
Technology for low cost detection of impurities and water treatment
One of the biggest issues particularly in developing and third world countries is clean water. Scientists see the potential of using nanotechnology for cheap detection and treatment that would make it affordable to get clean water.
Using molybdenum disulphide, it has become
possible to efficiently desalinate water using less energy. Here, thin film membranes
that have nanopores are used to filter water more efficiently.
Nanofabric paper towels for oil cleanup
These paper towels are made using tiny potassium manganese oxide capable of absorbing up to 20 times their weight. This will make it easier to clean up oil and avoid significant damage to the environment.
This technology is being used to help in detecting chemical and biological agents present in both water and air. In such cases, appropriate actions can be taken.
Some of the other applications of nanotechnology in our day to day life include:
As previously mentioned, ordinary microscopes cannot be used to view nanostructures given their nano size. For this reason, more advanced microscopes have to be used.
There are a number of microscopy techniques that can achieve this, they include:
This method involves several techniques that are used to observe the sample. Here, scanning tunneling microscopy, atomic force microscopy as well as chemical force microscopy is used for the purposes of characterizing nanostructures with either atomic or subatomic spatial resolution.
In this case, the sharp tip of an atom scans the surface of the sample allowing imaging through measuring current that is flowing through the tip or acting on it. Using this technique, it has become possible for scientists to not only manipulate the samples during product development, but also determine areas of improvement.
Typically, this microscopy technique's set-up includes a sharp tip on the cantilever of the microscope, a laser, a scanner, a position sensitive detector as well as control electronics. The technique works by measuring the force between the tip and solid surface. Here, scientists/technicians can capture images having detected the force as the tip is scanned across the sample.
*force acting on the tip in this case also represents the distance between the tip and atom surface.
This technique can be divided into Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Here, images are formed once the electron beam interacts with the specimen. This is due to the fact that measurable signals are generated as electrons are transmitted, diffracted or backscattered.
For TEM, electrons are used to form the image of the sample. However, with SEM, it is backscattered electrons as well as secondary electrons that are emitted from the sample that create the image.
Shalini Charurvedi1 and Pragnesh N Dave (2012) Microscopy in Nanotechnology.
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