What are nanosensors?
Every time a washing machine is used or a door automatically opens before you a thing called a sensor is hard at work trying to sense your presence. These things prevent accidents such as overflowing water inside a washing machine ( sensors are measuring the number of clothes to the amount of water needed ) These sensors also save lives in the form of airbag technology.
One of the differences between Nanosensors and sensors is their size. Nanosensors are either chemical or mechanical. these things are a smaller version of sensors hence it’s named nano-sensors. The tiny nano-sized sensors detect either minute particles or minuscule quantities of something. Something advantageous when it comes to dealing with things such as tumour imagining.
Why they are important.
As I previously mentioned nanosensors can be chemical sensors or mechanical sensors. They are used:
- For medical diagnostic purposes either as bloodborne sensors or in lab-on-a-chip type devices
- To monitor plant signalling and metabolism to understand plant biology
- As accelerometers in MEMS devices like airbag sensors
- To study neurotransmitters in the brain for understanding neurophysiology
- To detect various chemicals in gases for pollution monitoring
How Nanosensors Work
Sensor, transducer and detector are the components of a sensor system, with feedback from the detector to the sensor. Ease of execution are the main goals in designing a sensor.
Nanosensors usually work by monitoring electrical changes in the sensor materials.
Like chemical nanosensors, mechanical nanosensors also tend to measure electrical changes. The nanosensors used in the MEMS systems that car airbags depend upon are monitoring changes in capacitance. These systems have a minuscule weighted shaft attached to a capacitor. The shaft bends with changes in acceleration and this is measured as changes in capacitance.
Nano Fabrication
First fibre is secured into a pulling device for the process of heating and pulling. heat is then applied to the median of the fibre. lasers may be used for heating. after the pulling and heating is done the process that follows is the coating of the tapered end of the fibre, gold and silver are the best options. thermal vapour deposition while leaving
the distal end uncoated. Once thermal vapour deposition the fibre is secured in a thermal evaporation chamber this is to ensure uniform silver coating. Once this step in complete there are only two steps left as explained by the image below
The problems with Nano Fabrication and some solutions
Problems
1 Gold and silver are both rare and expensive as well as usually unsustainably sourced
2 Poor packaging makes it risky to ship Nanosensors
3 special lasers have to be used to heat the fibre as the fibre is very delicate
4 special machines are needed to pull the fibre.
Solutions
1 Use other materials to find cheaper and easier to find ones instead of aluminium, gold or silver.
Test better packaging in difrent enviourments.
source
Madekufamba, Melerin. Fabrication and Derivatisation of Nanosensors. Their Applications in Nano-Medicine.
