The applications and types of nanosensors are numerous, so to get an overview it can help to divide them into different categories depending on what they measure and how they work. The main three categories of measurements are physical, chemical, and biological. Furthermore, a useful distinction between the signals of the sensor is electrical vs optical. This article will shortly present each type and some of the applications.
- Physical Nanosensors
- Chemical Nanosensors
- Electrical VS Optical Nanosensors
- Outlook on Market
Physical nanosensors aim at measuring changes in physical quantities such as temperature, velocity, electric forces, etc. This has many applications in everyday life and in industries as these measurements, if analyzed by an algorithm, can tell whether a production line is working optimally, or a patient is sick or getting better. One company that uses physical nanosensors is Nanowear Inc., making wearable undergarments for finding a potential heart failure before it happens in chronically ill patients by looking at changes in the electric signals from our bodies.
Chemical nanosensors are used to detect different chemicals or chemical properties such as pH value. This is for instance useful when looking at environmental pollution or for pharmaceutical analysis. Typically, they are fabricated from different nanomaterials such as graphene or metal nanoparticles as these react to the presence of specific target chemicals that need to be measured[i].
An example of a chemical nanosensor is one used to detect the pH value of a liquid. By using polymer brushes coated with gold nanoparticles, a research group managed to build such a sensor that can detect the pH value using a spectroscopic method[ii].
In medicine and healthcare, biosensors can precisely detect tumors, pathogens, toxins, and biomarkers. They do that by converting the reaction of molecules into electrical or optical signals and have the advantage of being able to target very specifically what is wanted to be measured[iii]. When shrinking the size of an object, its surface to volume ratio becomes bigger, which is why nano-biosensors have a big advantage to larger biosensors, offering better sensing as the reaction with the targeted molecules happen more frequently.
The Taiwanese start-up Instant NanoBiosensors Co., Ltd. is an example of one within this domain. They use an optical fiber coated with gold nanoparticles and antibodies to detect various biological compounds[iv].
Electrical Vs Optical Nanosensors
The signals from nanosensors are often either electrical as with Nanowear Inc. or optical as with Instant NanoBiosensors Co., Ltd. One measures changes in the current or voltage, whereas the other measures changes in the properties of light which is then converted to an electric signal.
Optical nanosensors sometimes have the advantage of interacting little with samples as light of the ‘right’ wavelength can move more freely through them than a current can. This can reduce changes such as unwanted heating of what is being measured.
Many biosensors rely on optical signals such as biocompatible photoluminescent molecules for in vivo purposes which changes the light they send out when detecting an analyte. In addition, optical nanosensors have been developed to detect various ions such as oxygen, Ca2+, Mg2+, and more.[v]
On the contrary, a chemiresistor is an excellent electrical sensor, which works very well in detecting specific molecules by applying a current between two metallic electrodes to then observe changes in the current when a target molecule binds to organic ligands between the electrodes. This allows vast possibilities of engineering the sensor to target specific molecules as different properties such as the type of organic ligands can easily be changed.[vi]
Outlook on market Between physical, chemical, and biosensors, the market for biosensors is expected to experience the most growth within the next 6 years followed by the market for chemical nanosensors, according to AlliedMarketResearch[vii]. Based on that a lot of biosensors rely on using optical signals, it could be argued that optical sensors will experience more growth than electrical sensors. However, this will depend on many factors about the sensing abilities, price, and convenience of the sensor. The startup, Nanowear Inc., is a great example of where physical nanosensors using electrical signals offers great applications within a large sector in the market of healthcare.
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[i] Kurbanoglu et al., New Developments in Nanosensors for Pharmaceutical Analysis, 2019, Pages 141-170, accessed at: https://www.sciencedirect.com/science/article/pii/B9780128161449000055
[ii] Iryna Tokareva, Sergiy Minko, Janos H. Fendler, and Eliza Hutter, Journal of the American Chemical Society 2004 126 (49), 15950-15951, accessed at: https://pubs.acs.org/doi/abs/10.1021/ja044575y
[iii] Solaimuthu et al., Nano-biosensors and their relevance in tissue engineering, 2019, accessed at: https://www.sciencedirect.com/science/article/pii/S2468451119300790
[v] Benjaminsen, Rikke Vicki, Design and application of optical nanosensors for pH imaging in cell compartments, 2012, accessed at:
[vi] Hossam Haick, Introduction to Nanotechnology, Isreal Institute of Technology
[vii] Nanosensors Market Outlook – 2026, accessed at: https://www.alliedmarketresearch.com/nanosensors-market