Starter Toolkit Series: Nanotechnology
Part of my series demystifying basic concepts of new-age technologies to help spark curiosity in other young minds
What is Nanotechnology?
Almost everyone has heard of nanotechnology, but what is it really? Nanotechnology is science, technology, and engineering performed at the nanoscale, or rather in simpler terms ‘on tiny things’.
Nanotechnology has become a thriving industry that has created objects that are all around you, things from a glass mug that doesn’t break when it falls to a t-shirt that smells fresh even after days of use. Even Iron Man’s suit used nanotechnology!
Nanotechnology has an endless number of benefits, including improved manufacturing methods, water purification systems, energy systems, nanomedicine, better food production methods and more!
What are Nanosensors?
First, let me define what Sensors are: Sensors are devices that receive feedback from the surroundings and lead to a pre-determined action. For instance, sensors allow automatic doors to sense the presence of a person, sensors on roads detect the presence of a car and adjust the flow of light changes to the intersection based on that information. Sensors are even used to make sure washing machines don’t overflow! The world requires sensors to efficiently operate.
Nanosensors essentially work the same way as normal sensors except they detect minute particles or minuscule quantities of things. Nanosensors are a cross between nanotechnology and sensors and are a major part of nanotechnology.
Why are Nanosensors important?
Nanosensors possess very unique physical characteristics and many performance benefits such as quick response and mobility. Nanosensors can build a brand new category of devices that provide the base for “intelligent sensors” that are able to handle information processing, storage, and analysis. I expect that further research and advances will open new possibilities for the application of nanosensors in numerous fields, such as molecular-level diagnostic and treatment instruments in medication.
How do Nanosensors work?
There are 2 types of nanosensors: Chemical and Mechanical. Both types work by detecting changes in the electrical conductivity of a material but the key difference is that chemical nanosensors test for chemical concentrations and mechanical nanosensors detect movement.
Mechanical nanosensors are made up of nanomaterials. Whenever a nanomaterial is physically manipulated, its electrical conductivity changes. This change causes a response that can be measured using an attached capacitor because the physical change causes a change in capacitance.
Chemical (Carbon nanotube-based) nanosensors work by watching electrical charges within the sensor materials. For instance, when a molecule of nitrogen dioxide (NO2) is present it will strip an electron from the nanotube, which in turn causes the nanotube to be less conductive. If ammonia (NO3) is present it reacts with water vapor and donates an electron to the carbon nanotube, making it more conductive. By treating the nanotubes with various coating materials, they can be made sensitive to certain molecules and immune to others.
How are Nanosensors built?
Nanosensors are built through a process called nanofabrication. There are 2 main types of nanofabrication: top-down nanofabrication and bottom-up nanofabrication.
Starting from bulk material, the top-down fabrication process starts to modify and shape the material into the desired shape and size. The key to top-down nanofabrication is the art of lithography, which has been greatly improved to create patterns of smaller geometries with higher resolution.
Bottom-up nanofabrication is like building a tower. Bottom-up fabrication techniques place atoms or molecules one at a time to build the desired nanostructure. There are numerous other techniques that can be used for bottom-up fabrication, and some of these include vapor-phase deposition, atomic layer deposition, molecular self-assembly, and DNA-scaffolding.
What are some issues with Nanofabrication?
While nanofabrication, and nanotechnology as a whole, may seem like mature technology, there are some disadvantages/problems that are yet to be solved.
As the bottom-up approach creates products by building them up bit by bit it can be quite time-consuming, so scientists are researching the concept of self-assembly by placing certain molecular-scale components together spontaneously from the bottom-up into ordered structures.
While the possibilities and uses of properly regulated nanotechnology to help solve critical public health and environmental problems are endless, there is another side to the argument that says that there is much that is unknown about the health and environmental risks of nanotechnology. There is some research suggesting that nanoparticles may affect marine ecosystems, including chemical processes that are essential for microbes and aquatic animals. Since elements at the nanoscale behave differently, there are also many concerns when it comes to the safety of these particles.
Some fear nanoparticles in products applied to the skin will be able to migrate through cell membranes or other body structures that would normally be protected against larger molecules, with unpredictable and potentially harmful results.
Given the size of the particles used in nanotechnology, there’s a rational reason to worry about those particles being inhaled or absorbed in the skin with potentially toxic consequences. Nanoparticles are much smaller than asbestos, for instance, which has been linked to cancer and other health problems due to inhalation.
Next steps in the Nanofabrication process
In a bottom-up nanofabrication approach, known as molecular self-assembly, molecules are chosen in step with their ability to spontaneously interact and mix to make shapes with specific functions. Molecular self-assembly is a spontaneous method that can’t be controlled directly by laboratory equipment, thus it must be controlled indirectly. This is often done by carefully selecting the direction of the intermolecular interactions, referred to as “chemical control”, and carefully selecting the temperature at which these interactions happen, known as “entropic control”. Researchers understand that, as an example, when entropic control is extremely weak, molecules are beneath chemical control and assemble in the direction of the free sites available for molecule-to-molecule interaction. On the other hand, self-assembly doesn’t occur when entropic control is much stronger than the chemical control, and the molecules stay randomly spread.
Nanotechnology products today
There are a lot of very useful and interesting applications of nanotechnology that many companies are developing today. Some examples include:
- “Nanite” developed by Oceanit that uses nanotech to turn normal cement into smart-sensing cement to turn the road into a sensor
- Cosmetic products by L´Oréal that uses nanotechnology to transfer active agents such as vitamins
- “Smart fabrics” that use nanoscale sensors and electronics with capabilities for health monitoring, solar energy capture, and energy harvesting through movement
- Self-cleaning glasses called “Activ Glass” by Pilkington which uses nanoparticles to make the glass photocatalytic and hydrophilic
- “Double Core” tennis balls by Wilson that have a layer of clay nanoparticles which helps keep the air inside of the ball
- OLED TVs that use nanoparticles-based coatings for packing the OLEDs to protect them from environmental damages
The Future Potential
There are many possible applications for nanotechnology in the future but one major possibility has to do with solar panels. A study done by the US Department of Energy shows that nanotechnology has the potential to reduce the cost of harnessing solar power and increase efficiency. This will promote the usage of solar power which is a renewable and sustainable source of energy.
Another potential application is in pharmaceuticals. For instance, nano-based pharmaceutical products can be used as carriers for active pharmaceutical agents to parts of the body or could be used as therapeutic agents themselves.
There is also a lot of potential for applications of nanotechnology in the food industry. Nanoparticles can be used in food packaging to prevent the flow of oxygen and carbon dioxide in carbonated drinks, preventing oxidation and de-carbonation, and blocking the migration and permeability of gases in fresh food packaging. Nanoparticles such as silver and zinc oxide could be used in the packaging of some foods to prevent the growth of microbes such as yeast and mold.
There is also research in nanotech cures for cancer and viruses if patients could drink fluids containing nanorobots that can be programmed to attack the cancer cells and viruses. Nanorobots could also be programmed to perform delicate surgeries much more precise than modern methods.