How Small Particles Have a BIG Impact
The universe as we see it is marvelous enough. The oceans are so vast and deep that we have yet to explore more than 5% of them. Mankind has yet to step foot on Mars. However, there is another world, equally as bewildering, yet, too minuscule for the human eye to observe. This world is the world of nanoparticles and nanomaterials. These are particles with at least one dimension smaller than 100 nanometers (1 nm = 1x10-9 meter). The amazing thing about nanoparticles is that on this scale, these particles have different properties than their larger counterparts. In fact, classical mechanics, a sub-field of physics that had been accepted for centuries, can’t explain why these certain particles acted this way. This gave rise to quantum mechanics, which describes how things like photons (particles of light that have no mass) and atoms (the smallest units of matter that still retain properties of a chemical element) interact and behave. At this level, we can observe how light can act as both a particle and a wave. In the photoelectric effect, (an experiment in which light is shone upon a piece of metal with electrons) photons knock off individual electrons, suggesting their particle-like behavior. However, in our day to day lives, we see light refract, diffuse, and reflect in wave-like ways, resulting in phenomena such as rainbows. With our knowledge of nanotechnology, we can manipulate these materials on atomic/molecular levels, resulting in limitless possibilities.
Nanotechnology has already made great leaps and impacted numerous industries. For example, it has revolutionized the world of medicine. Nanomedicine, as it is being called, is medicine that is small enough to squeeze through the walls of blood vessels. This helps medicine reach the places where it needs to perform its job. In addition, nanomedicine has been effective at neutralizing free radicals. Free radicals react with other chemicals, taking electrons from other cells, thereby making them unstable and causing damage. Cerium Oxide, a nanomedicine, is a substance that neutralizes free radicals by allowing free radicals to receive electrons from cerium oxide instead of other cells. Applications of nanomedicine that are currently being looked into include nanoparticles that attach to tumor cells. These nanoparticles can deliver drugs directly and precisely to tumor cells, or even use heat and infrared light to attack tumor cells. An example of these nanoparticles at work include iron-oxide nanoparticles. Researchers at Dartmouth have created iron-oxide nanoparticles that respond to magnetic fields, attaching to tumor cells and generating heat from the magnetic fields to kill the tumor cells. The significant part of this development is that the concentrations of the nanoparticles on healthy cells should be low enough not to harm them. These applications of nanomedicine are still in development, but show a promising future.
Another remarkable application of nanotechnology is in nanomaterials. Nanomaterials have helped computers become smaller and less expensive for the public. By replacing carbon graphite with silicon nanotubes, we have created more efficient lithium ion batteries. Scientists have also created “super-silk” by feeding regular silkworms with carbon nanotubes or graphene and collecting the material from the cocoons of the silkworms. This material is twice as tough as regular silk and it is able to withstand 50% more stress before breaking. This material is also capable of conducting electricity. Scientists developing this nanomaterial face challenges, such as finding out how the silkworms actually produce this material and what is the optimal percentage of nanomaterials the silkworms should eat (in this recent experiment the silkworms were given food that was 0.2% nanomaterial by weight). This material could be used in the development of wearable electronics and medical implants.
One of the most remarkable and recent developments in nanotechnology was deemed worthy of a Nobel Prize. In 2016, The Nobel Prize for Chemistry went to Jean-Pierre Sauvage, Sir J. Fraser Stoddart, and Bernard L. Feringa, for the creation of molecular machines. These molecules are capable of controlled movements on an unprecedented scale. Jean-Pierre Sauvage was the first to contribute to this development by creating a chain that linked two molecules. Most molecules are connected by atoms that are linked with covalent bonds, in which these atoms share electrons. These covalent bonds usually inhibit molecules from rotating freely. However, these new molecules can rotate relative to each other with mechanical bonds. Sir J. Fraser Stoddart created a ring-shaped molecule attached to an axle that could shuttle up and down the axle. With all these tools, Bernard L. Feringa was finally able to invent a molecular motor that responded to heat/light by rotating in a particular direction. Refer to the attached image that illustrates how the molecular motor operates. With this molecular motor, Feringa created the first truly machine operated nanocar that responds to ultraviolet light. This is a truly remarkable advancement of our time. Possible applications of this technology are unknown, but we may possibly have another technological revolution on our hands involving molecular machines.
As we can see, there are a plethora of applications of nanotechnology, impacting numerous industries and fields of science. This kind of technology is unprecedented, and the future will introduce even more revolutionary ideas that will compound on each other until we live in an entirely new world.
Figure 1 - With the input of light (with a wavelength of 280 nm), the structure switches structures in an endothermic reaction. The molecule will revert to the original structure with the release of the same amount of energy in an exothermic reaction. The molecule will also move in different directions based on the surrounding temperature.
Works Cited
"Dartmouth Researchers Find Promising Results with Local Hyperthermia of Tumors." Understandingnano.com. N.p., 28 Feb. 2014. Web. 22 Nov. 2016.
Devlin, Hannah. "'Nano-machines' Win European Trio Chemistry Nobel Prize." The Guardian. Guardian News and Media, 2016. Web. 19 Oct. 2016.
Kowalski, Kathiann. "Nano Medicines Take Aim at Big Diseases." Science News for Students. N.p., 18 Aug. 2016. Web. 24 Oct. 2016.
Patel, Prachi. "Silkworms Spin Super-Silk after Eating Carbon Nanotubes and Graphene." Scientificamerican.com. Scientific American, 09 Oct. 2016. Web. 14 Oct. 2016.
"Press Release: The Nobel Prize in Chemistry 2016." Nobleprize.org. Noble Prize, 5 Oct. 2016. Web. 22 Oct. 2016.
