Nanosensors & Nanofabrication: Solving Big Problems with a Smaller Solution

Over the past few years the term Nanotechnology has been appearing and something that will surely impact our future. But, what exactly is nanotechnology? It is the study and use of structures between 1 and 100 nanometers in size. For example the width of a paper is about 10,000 nanometers. There are many terms associated with Nanotechnology, but today I will be focusing on Nanosensors and Nanofabrication.

Why go Nano?

There are many benefits to using nanostructures, some may depend on the material being used. For example if you carve the graphite of a pen to a nanometer you will get a material called graphene. Not only is it very strong, but also absorbent so that it can clean up pollution such as oil spills and preserve water. Also the size of the structure allow it to access narrow places such as your bloodstream.

Nanosensors and how they work

Nanosensors are very small sensors that measure physical quantities and convert that information into signals that can be analyzed. Think about it like an Antman and Spiderman hybrid where you can get even smaller than an ant but also have the spidey sense to predict what danger may be on it’s way so you can make a plan to stop it. The thing is, nanosensors are much better and important than spidey sense. Different nanosensors can detect different signals including biomedical, physical, electrical, chemical and even mechanical signals. This can impact industries such as health care, environmental, aerospace, agriculture and construction.

For example in the Agriculture industries nanosensrs can detect the efficiency of plants and monitor them to ensure their growth is proper. Source: Frontiers Environmental and Science

Nanosensors mainly work because of electricity. There are two main types of sensors, mechanical and chemical along with a smaller group called biosensors. Mechanical sensors work by being physically moved by the outside world, resulting in the change of electrons. This occurs when a shaft is bent into a different shape effecting the electric capacitance. The sensors will pick up any change in the electric capacitance which allow for data to be collected.

Chemical Sensors work based on there name, when correct chemical reaction occurs few electrons may be displaced creating an electric current that runs up a nanotube. For example an interaction with nitrogen dioxide can remove an electron. The sensors will pick up on the change of electrons and tranfers the data.

This image shows that even in a biosensor, when antigens lock on to antibodies is can effect the electrons allowing the sensor to measure data Source: Semantic Scholar

Nanosensors are so small, so why are they Important?

Even though nanosensors are small you should make some brain space for them. Lets say cancer just launched an attack on you, a disease which 8.2 million people die from yearly. Most cancers can be treated if recognized early. If a doctor could insert a nanosensors into your bloodstream to detect any forms of abnormalities or cancer and send the information to an external wireless device where doctors can determine further treatment.

This image shows how nanosensors will work when placed into a patient. Source: Semantic Scholar

Most problems can be solved, it is just a matter if it can be recognized early, and that what nanosensors do. They sense the future. Nanosensors can be applied to many industries effecting the way they operate, for example with health care, agriculture as mentioned before, and even food. Today, grocery markets are attempting to implement nanosensors in meat products to measure oxygen levels and determine when and if foods may be rotting.

This image may be the future of grocery shopping, ensuring food is not expired. Source: Research Gate

Nanofabrication: The Process

There are two main ways that nanostructures are created, the bottom up approach and top-down lithography. Top-down lithography works by starting with a larger piece of material that is more manageable, and slowly breaking it down. Additional layers can be added through the process of etching and deposition. Specifically writing, etching, and printing patterns on to nanostructures is nanolithography. Think about it like an ice sculptor, one who starts with a piece of ice and slowly work at it, only down to a nanoscale level.

The bottom-up approach is almost the opposite, where you are starting with almost nothing, and slowly piecing together atoms which form components and eventually nanostructures. This is very similar to Lego, where you can create a structure by adding one brick at a time. Self-assembly can also be classified as a bottom up approach. Instead of an external force placing the atoms together, the atoms do it themselves, just like a plant is able to produce it’s own food. An example of this would be quantom dots.

The process of nanofabrication from both methods. Source: InTechOpen

What’s the Catch?

If making devices that can detect cancer isn’t amazing I don’t know what is. It is too good to be true so… what’s the problem with nanofabrication? Regarding the Top Down method a lot of materials are being wasted since you only need structures on the nanoscale. Also as you get smaller it gets harder to carve in the necessary patterns. It will also costs a lot of money to receive new machines as nanotechnology advancements are made. Whereas bottom-up is more preferred, but still not ideal. Building atom by atom and adding in complex patterns gives you higher precision, but can be very tedious and time inefficient.

Solving the Problem?

Going into the future the self-assembly method seems to be the best option, because it wastes less resources and the atoms will assemble themselves so it’s less tedious. One main problem is it takes a long time for this process and other methods to occur. So possibly testing out self assembly in different environment, in terms of temperature, magnetic fields, chemicals and more can speed up the process. Also connecting this with AI so that it can understand the properties and simulate different scenarios.

Moving forward nanotechnology is something constantly developing and changing both itself and industries. Improving the nanofabrication process and developing new applications for nanosensors will be a big step forward, but only time will tell.

Resources: https://medium.com/@qukevin99/nanosensors-what-they-are-and-what-they-need-d34781fef7a6

https://www.britannica.com/technology/nanotechnology/Nanofabrication

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