Biosensor is an analytical device that has a combination of biological detecting elements such as a sensor system and a transducer(sensor). In simple words, it is a scientific device that converts a biological response into an electrical signal.
A biosensor is the short form for a biological sensor. The biological element in this sensor could be an enzyme, a nucleic acid or an antibody. How does it work? The bioelement communicates with the analyte being tested and the biological response is converted into an electrical signal by the transducer(sensor).
Medical biosensors play a huge role in medical diagnostics and patient monitoring. Biosensors are uniquely suited to many diagnostic and real-time detection challenges due to their use of biological molecules, tissues, and organisms.
In medical field, Glucose biosensors are widely used in clinical applications for diagnosis of diabetes and its usage at home accounts for 85% of the world market.
Biosensor field has grown widely into different ranges of sensors based on their application, right from immunosensors to thermal biosensors. So, let's understand 7 different types of biosensors and their uses among them.
1. Electrochemical Biosensors
Due to the use of electrodes, these biosensors are simple and cost effective. And they can be easily miniaturized for fabrication of implantable biosensors. This technique is commercially used for DNA detection, enzyme-based tests such as glucose and in-field monitoring.
In general, an electrochemical biosensor is based on an enzymatic catalysis reaction that consumes or generates electrons. These enzymes are known as Redox Enzymes. This biosensor's substance typically includes three electrodes: a counter, a reference, and a working type.
Moreover, there are four types of electrochemical biosensors: Amperometric, Potentiometric, Impedimetric and Voltammetric Biosensors.
Immunosensors were identified based on the fact that antibodies have a high affinity for their specific antigens, such as antibodies that specifically combine to toxins or pathogens or interact through host immune system components. These biosensors are based on affinity solid-state devices in which the immunochemical reaction can be connected to a sensor.
Because of the specific binding between antibody and corresponding antigen, immunosensors have high selectivity and sensitivity that makes them a suitable platform for a variety of applications, particularly in the medical and bioanalysis fields.
There are four types of immunosensors based on the type of transducer: electrochemical, optical, microgravimetric, and thermometric. Electrochemical immunosensors have been more perfected among immunosensors due to their simplicity and ability to be portable and for automated detection.
3. Thermal Biosensors
Thermal detection biosensors use one of the fundamental biological reaction properties, such as heat production or absorption for changing the temperature when the reaction occurs.
This sensor can be created by connecting the molecules of an immobilized enzyme with temperature sensors. When the analyte and approaches come into contact, the enzyme's heat reaction can be measured and adjusted in relation to the analyte concentration.
The total heat generated can be proportional to the molar enthalpy and total number of molecules in the reaction. Temperature is normally measured using a thermistor known as an enzyme thermistor. Since they are sensitive to thermal changes, temperature sensors are ideal for some applications.
Unlike other types of transducers, thermal sensors do not require regular calibration and are insensitive to the sample's electrochemical and optical properties. These sensors detect pathogenic and pesticide bacteria.
4. Thermometric Biosensors
There are multiple biological reactions related to the production of heat, and these serve as the foundation for thermometric biosensors. These sensors are commonly known as thermal biosensors.
These are used to measure serum cholesterol. When cholesterol is oxidized by the enzyme cholesterol oxidize, heat is produced that can be calculated. These biosensors can also be used to measure glucose, urea, uric acid and penicillin G.
5. Wearable Biosensors
The wearable biosensor is a digital device worn on the human body in various wearable systems such as smartwatches, smart shirts, and tattoos that measures blood glucose, blood pressure, heart rate and other parameters.
Nowadays, we can see that these sensors are sending a signal of progress to the world. Their improved usability and ease of use can provide an authentic level of insight into a patient's real-time fitness status. This data accessibility will allow for better clinical decisions, improved health outcomes and more capable use of healthcare systems.
For humans, these sensors may help in the early detection of health issues and the prevention of hospital treatment. The potential for these sensors to reduce hospital stays and readmissions will surely raise positive awareness in the upcoming future.
6. DNA Biosensors
The development of DNA biosensors can be based on nucleic acid identification techniques for analysis of simple, rapid, and cost-effective genetic and infectious disease testing. Furthermore, the exact detection of DNA series is important in a variety of fields such as food analysis, clinical and so on.
When compared to traditional hybridization, these sensors and gene chips have numerous advantages due to their enormous potential for obtaining specific data in a simpler, cheaper and faster manner.
Furthermore, these sensors have been increased but fundamental research is still required to improve sensor technologies, detection plans, analytical instruments and procedures.
7. Optical Biosensors
The optical biosensor is a device that measures using an optical principle. They make use of fiber optics and optoelectronic transducers. The term optrode is a combination of the words optical and electrode. These sensors are primarily composed of antibodies and enzymes like transducing elements.
Optical biosensors enable equipment sensing that is secure, non-electrical and inaccessible. Another advantage is that they frequently do not require reference sensors because the comparative signal can be produced using a light source similar to the sampling sensor.
Direct optical detection biosensors and labelled optical detection biosensors are the two types of optical biosensors.
Lastly, we conclude that biosensors have been used for a wide range of healthcare and diagnostic purposes. The medical biosensor is a highly relevant and effective tool for measuring glucose levels and blood pressure. In the future, biosensors will be crucial for clinical diagnosis, health management, and research so that people can live normal lives and clinicians can make informed decisions about treatment.