Nanotechnology: The World on a Miniature Scale
Imagine you’re building a house, out of brick and mortar. Simple enough task, right? Now imagine that the bricks are all the size and shape of beach balls, and you can only move them using a pair of telephone poles. If that seems tricky to you, you’ve got an idea of what construction at the nanoscale is like: molecules are really small and awkward to assemble, and physical tools are too big to use precisely. The ability to construct nanoparticles and nanomachines, however, may be the key to revolutionizing health, electronics, computing, drug manufacture, biotechnology, and even conventional building, just to name a few possibilities.
But using those telephone poles like chopsticks just ain’t gonna cut it for the creation of products on a scale where we can’t even see the bricks. And that’s where another recent advancement, technically named “additive manufacturing”, but colloquially and more excitingly known as “3D printing” comes in. On the macro scale (that’s the one that we live on!), we’ve advanced 3D printing technology so far that we’ve even printed a tiny human liver, shown below.
So what could we achieve on the nanoscale, and what advantages would this so called nanofabrication bring? Recently, researchers in Korea have been able to print free-standing nanowalls, which is one step closer to being able to print more complex nanostructures. These nanostructures could have some very interesting, and very complicated properties.
Richard Feynman, who, in addition to contributing greatly to quantum mechanics, also participated in the Manhattan Project.
It’s generally held that nanotechnology was first described in 1959 by a prominent American physicist, Richard Feynman. In a lecture titled “There’s plenty of room at the bottom”, he talked about being able to manipulate and build machines from individual atoms, synthesize chemicals mechanically (in much the same way that RNA creates proteins), and revolutionize computing, by being able to fit an exponentially larger amount of processing power into the same surface area. 51 years later, we’ve started down the path of achieving the ideas he envisioned. The young scientific fields of mechanosynthesis and molecular electronics both take their origins from the field of nanotechnology, and are well on their way to achieving what Feynman envisioned. Just this week, scientists at Penn State University managed to propel nanoscale motors inside a living human cell for the first time.
Optical Microscope image of nanomotors in a human cell.
Nanotechnology, as a scientific discipline, truly began in the 1980s, when we first invented microscopes that allowed us to see individual atoms. Today, we define nanotechnology in terms of nanomaterials. A nanomaterial is any material, structure or particle that has at least one dimension on the scale of 1-100 nanometers. Nanotechnology, hence, is the manipulation of any nanomaterial on this scale. To give a better understanding of the scale at which we are working, here’s a mind-boggling fact for you – one nanometer is one eight thousandth of the width of the average human hair. It’s the scale that allows us to put the encyclopedia Britannica on the head of pin. But what’s so special about using comparatively miniscule particles of a substance?
The smaller the blocks, the larger the reactive area.
There are two concepts at play here. The first is the idea of surface area. For those of you who have done some chemistry, you know that having the largest possible surface area allows a chemical reaction to occur at the maximum possible speed, because it enables the reacting chemicals to come into contact with more of each other. This is why a crushed pill will dissolve more quickly than one that is intact. The smaller the particles of the pill are, the faster it will dissolve. This principle of relative surface area holds true on the nanoscale. As we decrease the size of our particles, a greater percentage of atoms are found at the surface. Hence, although a particle of length 30 nm has only 5% of its atoms on its surface, a particle or 3 nm has 50%. Because of this, a mass of 3 nm particles will be ten times more reactive than the same mass of 30 nm particles. This means that we can use very small amounts of a substance to achieve the same reactivity that we would have previously needed a much larger amount to achieve.
The second concept is the effects of quantum mechanics as scale decreases. Quantum effects can change the optical, electrical and magnetic behavior of nanomaterials (compared to their larger-scale counterparts). Additionally, changes can be seen in the mechanical properties of many materials at this scale. These factors allow us to create weird and wonderful products, such as nanocrystalline nickel that is as strong as steel, or quantum dots, which are essentially tiny semiconductors.
Understanding all this, we’ve started doing some wonderful things. In drug manufacture, nanotechnology is used in a procedure known as bioprinting, where nanoparticles magnetize cells into 3D structures, allowing high-speed testing of substances against human tissue. In the electronics industry, use of nanoscale techniques has allowed us to create flexible and transparent components, a step towards highly portable high performance computing. One last example is our recently developed ability to “teach” nanoparticles to recognize cancer cells, thereby allowing a more targeted medical approach.
Nanotechnology is a field of science and engineering that has only begun to scrape the surface of its potential. We’ve build megastructures, and we’ve been to space. The most exciting endeavors of this next century, though, might be almost invisible.
Sources:
Tiny 3D printed human liver: http://www.3ders.org/articles/20131109-tiny-3d-printed-human-liver-can-survive-for-up-to-40-days.html
3D Printed nanowalls:http://www.nanowerk.com/spotlight/spotid=34275.php
There’s Plenty of Room at the Bottom:http://www.zyvex.com/nanotech/feynman.html
Mechanosynthesis: http://en.wikipedia.org/wiki/Mechanosynthesis
Molecular Scale Electronics:http://en.wikipedia.org/wiki/Molecular_scale_electronics
Nanomotors move inside living human cells:http://phys.org/news/2014-02-nanomotors-cells-video.html
80,000 nanometers is the width of a human hair:http://phys.org/news/2014-02-nanoparticles-nanosafety-big-picture.html
Introduction to Nanotechnology:http://www.nanowerk.com/nanotechnology/introduction/introduction_to_nanotechnology_3.php
Nanotechnology: http://en.wikipedia.org/wiki/Nanotechnology
3D bioprinting for drug screening:http://www.nanowerk.com/nanotechnology_news/newsid=34247.php
Flexible electronics:http://www.nanowerk.com/spotlight/spotid=34351.php
Targeting cancer cells with nanoparticles: http://phys.org/news/2014-02-cancer-cells-nanoparticles.html
