Face recognition, smoke detectors, automatic doors… These are all examples of sensors that we interact with in our day to day lives. We know they exist because we can see them, built into gadgets, or when we look up to see an overhead scanning our presence. Lets say that one day, all these familiar devices would be shrunken down to an unimaginable form that can not be seen with the naked eye. Lets also say that these little devices will become the conventional way to monitor your health, measuring at the second. Scientists and engineers are making this a reality with the development of nanosensors, and we should expect to see an increase of its usage in our lifetime.
Don’t let the form factor of a nanosensor fool you to its capabilities, nanosensors work exactly just like the sensors we interact with in our everyday lives, with the exception that they are engineered to detect changes on the microscopic level. The term nanosensor is not confined to only mechanical-esque sensors, in fact nanosensors may include a small test strip of paper that can detect microscopic, atomic changes.
Putting the “nano” in sensors:
As explained previously, nanosensors work just like the sensors we interact with everyday so that explains the “sensors” part of the term nanosensor, but what does the prefix “nano” add to its definition?
Go feel your hair. I’d assume if you had hair, you’d have a lot, and if you don’t, (because that is a bold assumption) take a stuffed animal or any toy with faux hair. Now try getting hold of one strand, yeah I know its difficult. Why? Well, the answer is pretty simple: hair is extremely short in width and is small to pick up. So you go got the idea of nano being an extremely small measurement, which would define the term “nanosensor” as a heck of a small sensor.
Nanosensors can detect anything from 1 nanometre — 100 nanometres.
Alright, put this into perspective: If a single strand of hair is 50,000 –100,000 nanometres, imagine the capabilities a nanosensor has by detecting changes multiple decimal places smaller relative to the size of a strand of hair. Pretty crazy huh?
How do nanosensors work?
So you get the idea that nanosensors have a task to detect changes just like how automatic doors detect a change in movement, but in what way? There are 2 distinct classifications for nanosensors that determine its function: Active and Passive. A camera would be a perfect comparison to describe these two terms in action.
In the image, we can see that the light source is projecting a light ray onto the environment it is set to capture. This is an example of how an active nanosensor works, by being able to send rays remotely, similar to how a nanosensor would project signals remotely. Now if the light source represents an active nanosensor, that would leave the lens of the camera to represent as a passive nanosensor, but why? Passive nanosensors operate using external factors, such as this camera using light in its environment to operate.
Now from these classifications, nanosensors are are also assigned a specific task to either detect energy signals from physical or chemical changes.
Physical nanosensors:
- Measures properties such as temperature, position and pressure
Chemical nanosensors:
- Classifies a detected chemical substance and/ or its concentration
Nanosensors used today— An application
Nanosensors are currently and most typically used in pharmaceutical research, but in the future, we should see nanosensors affecting our daily lives for everyday uses such as water monitoring, which can be applied in swimming pools and food display quality which can be applied in supermarkets.
Lets get back to talking about active and passive nanosensors. Imagine you are a scientist researching about transmission of a deadly pathogen. With an active sensor, you can receive signals that can be received remotely through electromagnetic energy that the sensor creates. This sensor can be in any type of water reservoir such as a lake that can send signals when a pathogen is detected.
How are nanosensors made?
Nanosensors are made through a process called nanofabrication, which also is the same process for any “nano” material. Nanofabrication has 2 approaches: Top down fabrication and Bottom up fabrication.
Top down fabrication:
- Can be compared to sculpting from a block of stone, base material of blocks are carved to its shape. Examples of processes that include top down fabrication includes top down lithography and plasma etching
Bottom up fabrication:
- Can be compared to building a brick house, components such as molecules and atoms are stacked individually into its desired structure. A popular example of this process includes atomic layer deposition
Problems with Nanofabrication:
Both techniques have disadvantages but have advantages over each techniques disadvantage.
- The top down fabrication method is costly and involves a lot of equipment to be purchased.
- The bottom up fabrication method is less costly than the top down fabrication method, however, this method is much more time consuming.
Writer’s note: How can the problems with Nanofabrication be improved?
Nanotechnology is a new type of technology that is still being developed and is yet to have commercial use. I believe that until scientists develop some form of a commercial-pharmaceutical related product that can be distributed to a large community, consumers can properly evaluate the effectiveness of the product. If a trending flaw is apparent within a large testing group, results and diagnostics will reflect that flaw. Nobody creates their magnum opus on their first attempt, they are continuously refined over and over again, and the most time efficient method to do this would be to distribute this technology to a large community. This means to share blueprints and project outlines between work teams and co-operating with organizations overseas to accomplish a common goal. Developing your masterpiece isn’t an individual task for yourself, its a group effort directly or indirectly: from acquiring knowledge from others through articles without ever interacting or, meeting with your friend who has a plethora of knowledge on a subject area.
