Written by Georgia Vasiliki Gkountana and Maria Ines Berrojo R.M.

So, we keep hearing about biosensors, which have jumped in our lives for good know, providing easy, highly sensitive and rapid measurements, and combining low costs, and time- and trouble-saving. Since biosensors are an important aspect in science, for example they are used as tools in medical, environmental, food, and pharmaceutical field and since SensUs is all about biosensors, we thought it would be nice to give you an idea about what the biosensors are.

So, if we are looking for a definition, a biosensor is an analytical device that is sensitive to a physical or chemical stimulus that converts a biological response into an electrical signal.

Some physical stimuli: temperature, pressure, electric potential, light intensity.

The most prominent example for a chemical stimulus is the glucose concentration in the blood. Glucose biosensors are widely used by many people, especially diabetics, offering a very instant knowledge about their glucose levels, which can prevent the unwanted effects of blood glucose increase in these people.

The biosensor consists of three main components (as seen in the figure 1):

  1. A biological component for sensing the presence and concentration of a substance (detector).
  2. A transducer device.
  3. Output system.

The “stimuli” we want to detect using a biosensor are called biomarkers (= a measurable indicator of some biological state or condition) or analytes (i.e. substances being analyzed). Examples of biomarkers: glucose, ethanol, drugs, pollutants, proteins, nucleic acids.

Then, we have the biorecognition molecules (detectors), which are used to detect the specific target analyte. The biorecognition molecules can bind their targets with specificity and affinity. Examples of biorecognition molecules: enzymes, antibodies, aptamers, nucleic acids.

The recognition of the biomarker by the biorecognition molecule, will lead to the production of a signal, which can be either optical, electronic or magnetic, and finally this signal is measured by the device and gives a certain information that can be read and understood by the user.

Feel free to contact us for more information or for any interpretation; we will be glad to help!

Figure 1: Main parts of a biosensor.

References used:

  1. Bhalla N, Jolly P, Formisano N, Estrela P. Introduction to biosensors. Essays Biochem. 2016 Jun 30;60(1):1–8.
  2. SensUsCompetition. What is a biosensor? [Internet]. 2019 [cited 2020 Dec 6]. Available from: https://www.youtube.com/watch?v=W95w3D2ZtUk.
  3. Karunakaran C, Rajkumar R, Bhargava K. Chapter 1 – Introduction to Biosensors. In: Karunakaran C, Bhargava K, Benjamin R, editors. Biosensors and Bioelectronics [Internet]. Elsevier; 2015 [cited 2020 Dec 6]. p. 1–68. Available from: http://www.sciencedirect.com/science/article/pii/B9780128031001000013.
  4. Bhattarai P, Hameed S. Basics of Biosensors and Nanobiosensors. In: Nanobiosensors [Internet]. John Wiley & Sons, Ltd; 2020 [cited 2020 Dec 6]. p. 1–22. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1002/9783527345137.ch1.
  5. Fatoyinbo HO, Hughes MP. Biosensors. In: Bhushan B, editor. Encyclopedia of Nanotechnology [Internet]. Dordrecht: Springer Netherlands; 2012 [cited 2020 Dec 6]. p. 329–45. Available from: https://doi.org/10.1007/978-90-481-9751-4_129.

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