Nanotechnology has been around for about 40 years, yet most people don’t know anything on the subject. So what exactly is it?
Let’s start by looking at normal sensors. Sensors are devices which measure physical properties and records or responds to them thanks to electrical signals. Now, what about nanosensors? They are essentially very small sensors that detect properties such as temperature and conductivity on the nanoscale. There are many types of nanosensors: mechanical, photonic, optical, biological, electromagnetic, chemical and more. Each type reacts or measures something different. For example, mechanical nanosensors measure electrical changes and photonic nanosensors react to chemical stimulation.
Creating minuscule sensors isn’t easy. But, researchers have discovered 3 techniques for nanofabrication: top-down assembly, bottom-up assembly and self-assembly. Top-down assembly consists of etching or carving into a material to get the desired form. On the other hand, bottom-up assembly involves moving and assembling molecules and atoms. This builds starter molecules which are then used to assemble the nanosensor. Finally, the self-assembly technique uses molecular components that automatically assemble themselves with the help of UV radiation, heat, mechanical stress or chemicals.
Nanosensors have multiple uses in different fields. For example, they can be used to monitor the environment by sensing pollutants and dangerous substances like mercury in the air and water. In the medical field, nanosensors can be used to detect viruses and bacteria or to measure the temperature of living cells. Additionally, the food industry is experimenting with using nanostructures in food to increase solubility and protect food during storage and manufacturing. They are also using nanofabrication to create new packaging materials.
Nanosensors can measure properties in multiple ways. Most use electrical signals to achieve this. For example, nanotube sensors can change the amount of electrons in the nanotube when a certain molecule is present. By changing the amount of electrons, the nanotube’s conductivity changes, indicating the presence of a certain molecule. Mechanical nanosensors also use electrical signals to detect changes in capacitance. However, these sensors use a shaft attached to a capacitor. With acceleration, the shaft bends which indicates a change in capacitance.
What researchers have achieved with nanofabrication is impressive. However, there are still some problems with the techniques being used. The top-down method has only just reached the nanoscale, meaning that the sensors capabilities are reduced compared to nanosensors fabricated with other techniques. The bottom-up method does reach the nanoscale, however it is costly and very slow. The self-assembly technique also has some flaws: it depends heavily on the particles’ characteristics, meaning that it’s currently unpredictable and random. However, there is a way to improve this process. By using artificial intelligence and machine learning, we can analyse interactions between molecules to make a database that can accurately predict the outcome of the self-assembly process. This would significantly speed up nanofabrication since nothing would be random.
Nanotechnology is very impressive, and with the help of other upcoming technologies, it has the possibility to do even greater things.
