People assume that small is equivalent to weak. What most people do not know is that being small can have its advantages. Small things can fit into small places. One of the most powerful sensors and detection technologies is smaller than you could ever imagine. Nanosensors; sensors on the nanoscale.
What are Nanosensors?
First of all, what even is a sensor? Sensors are devices that detect or measure physical properties which are recorded and responded to. One common sensor is smartwatches. These watches have the ability to measure different bodily functions like temperature and heart rate. So how are nanosensors different? Well, the simple and self-explanatory answer would be that they are just small (nano) sensors. When we talk about the measurements of these tiny sensors we refer to them in nanometers. 1 nanometer is SO small that it is equal to one billionth of a meter. Think of it this way — A human hair is about 100,000 nanometers wide. In short, these are sensors in the nanoscale that can detect different signals in different environments and then translate them into quantitative values that we can detect and analyze.
Nanosensors can be classed into 4 different groups. Let’s take a look at them.
- Optical Nanosensors: Continuously monitors chemical or chemical processes.
- Biological Nanosensors: Great and efficient for dealing with substances that are biologically active
- Chemical Nanosensors: Great for determining the concentration of chemical substances
- Physical Nanosensors: These nanosensors are most helpful and efficient when they are measuring physical properties This can be things like temperature and flow
Why Should I Care?
You might be asking yourself, why does this even matter? How are nanosensors so different from normal sensors? The most obvious advantage is the fact that nanosensors operate on a smaller scale which allows them to go places that sensors didn’t have the ability to go before. And since they are smaller, they require a lot less power to operate and are even quicker to react. But nanosensors also have a greater sensitivity and specificity than our usual sensors, therefore, they are way more accurate.
Nanosensors may be small and tiny but that doesn’t stop them from being even more powerful and it doesn’t stop them from making a huge impact. Nanosensors will also impact many industries; one of them being the medical industry. Let’s take a look at the field of medicine. One important area of medical diagnostics is catching medical problems early enough in the process. A lot of the time, patients will not notice or experience symptoms until later on. When those symptoms finally start developing the issue may have already augmented and would be harder to stop. But nanosensors have the potential and ability to detect these medical problems at early stages and save many lives.
Another example of an application is in detecting chemicals in gases. This can be applied to help with pollution monitoring.
How do these nanosensors work?
Now that we know what these nanosensors are let’s learn a bit more about how they work. But out of all the types of nanosensors, there are two main types:
- Chemical Nanosensors
- Mechanical Nanosensors
Chemical nanosensors are usually composed of two basic components that are also connected. There are chemical (molecular) receptors and physiochemical transducers. In the majority of chemical nanosensors, the receptor interacts with the analyte (substance whose chemical parts are being monitored and measured) molecules. Chemical nanosensors work by measuring the change in electrical conductivity of the nanomaterial once an analyte. The good thing about using these nanomaterials is that they have high electrical conductivity which will reduce any binding or absorption of any molecules. The nanosensor can detect this Changement and that’s what it measures.
Mechanical Nanosensors also work by detecting changes in electrical conductivity of the material, but there is a difference. Mechanical nanosensors can have their electrical conductivity physically changed or manipulated. The nanosensor can then sense this. It is measured by a capacitor which is an electronic part that can store electrical charges.
How can something so small be made?
How can something smaller than the width of a human hair be created? If it’s so small that we can’t even see it, how do we even manage to make it? The answer to that is nanofabrication. Here’s where it gets a bit tricky. Scientists can take two different approaches to nanofabrication. There’s the top-down fabrication and bottom-up fabrication.
Top-down fabrication is essentially just carving a base to the form or shape you are trying to fabricate. It’s kind of similar to carving a sculpture.
Bottom-up fabrication is a different approach. You start with small molecules and atoms and place them like lego. One on top of another until you finally have the shape that you wanted.
Although the process of nanofabrication seems great there are still some problems with it.
- very costly which is not ideal
- boundaries to how perfectly detailed you could go
Bottom-up fabrication :
- using such small individual particles being placed can be super time consuming
- many limits to how big the nanosensor can actually be
So now you see, being small isn’t so bad after all. Being small is great and anything small can do great things. So before you judge an item based on its size, remember these nanosensors 😉.