Electrochemical biosensors have been researched for a long time. There are several different types of electrochemical biosensors being researched or already in the market. Techniques, methods, and materials all play a factor in the creation of electrochemical biosensors. Technology constantly moves forward, and the advances in other arenas are sparking change inside of the healthcare field. There advances are being made to ensure this technology evolves as new breakthroughs are made, and it’s important to stretch the current research boundaries for the continuation of those breakthroughs.
Biosensors were first considered by Leland Clark and he brought the principle to the attention of the science community in 1962 (Pohanka and Skladal 57). In 1975, the first commercial biosensor entered the market (Pohanka and Skladal 57). Converting biological information into an electronic signal that can be easily analyzed is a very complicated and complex endeavor (Grieshaber et. al. 1401). This is a blending of biological systems to an electronic device; its taking something foreign and making it operate inside the same parameters so that information can be gather and analyzed. In the biosensor, the bioelectrochemical element is the main component of transduction, which allows the use of electrical properties for information extraction from biological systems (Grieshaber et. al. 1404).
There are several types of biosensors, and they use different types of methods to achieve the same result: a measurable signal (Pohanka and Skladal 58). The types of electrochemical biosensors are potentiometric, amperometric, conductometric, and impedimetric (Grieshaber et. al. 1404). Field affect has also been used as a variation of the standard potentiometric that uses a gate electrode (Grieshaber et. al. 1405). It is also important to mention the method of Cyclic Voltammetry, which is technically the use of the amperometric technique, because it is an umbrella term that includes a variety forms: polarography, normal pulse, linear sweep, reverse pulse, differential staircase, and differential pulse, to just name a few (Grieshaber et. al. 1409). Each type of technique has its own strengths and weaknesses, and practical applications, which on occasion can overlap each other (Grieshaber et. al. 1418).
There are several characteristics that all biosensors have in common. First, the biocatalyst needs to be very specific for analysis, be able to be maintain stability under traditional conditions, and show assays with a low level of variation (Grieshaber et. al. 1402). Also, the reaction shouldn’t be disturbed by or require things such as stirring, changes in temperature, or a PH shift, to minimize the need to pre-treat samples (Grieshaber et. al. 1402). Lastly, the response must be accurate, reproducible, precise, linear, and the sensor itself should be inexpensive, as small as feisable, portable, and should not be overly complex (Grieshaber et. al. 1402).
Even with all the established techniques and methods, researchers are continuing to find new ways to improve electrochemical biosensors. One of the biggest areas of advancement has been the use of nano-objects, more specifically nanowires, to create faster, more efficient, and smaller devices (Grieshaber et. al. 1415). Nanowires are highly-sensitives electrodes with nanometer range diameters, which is why they are being used more for biosensing (Grieshaber et. al. 1415). Because of their miniscule diameter, when compared with their length scale, they are sometimes called quantum wires or one-dimensional structures (Grieshaber et. al. 1415). Nanowires have an unprecedented thinness, which results in having a lesser amount of unaffected volume, that decreases the chances of uninterrupted conduction (Grieshaber et. al. 1416). Nanowires have been a great advancement for electrochemical biosensors because they are so comparable in size to the biochemical analytes they interact with, and they also are sensitive to surface disturbances (Grieshaber et. al. 1416).
Over the course of the lifeline of the biosensor field, it has changed and made use of various techniques and methodologies. As everything has progressed and technology has evolved, the complexity of the field has expanded in ways no-one suspected. When considering what type of new experimentation could be explored inside this field, the possibilities seem endless. If it is considered that biosensors can be used to examine bodily fluids, environmental samples, food samples, and cell cultures (Grieshaber et. al. 1402), it’s not much of a leap to consider that a biosensor could be created that would monitor a patient’s blood to ensure medications that require very specific dosage level stay at the proper medicinal level. In fact, it would not be that much different than biosensors used for glucose. It would come down to finding which enzyme would be most productive; the enzyme is very likely to be different for each type of medication that would be monitored.
There are many different types of electrochemical biosensor technologies and methodologies. However, there is common thread between them all, especially when it comes to purpose. This field will continue to see more and more advancements as the technology evolves and new technologies are introduced. Nano-objects, specifically nanowires, have already shown what a large impact a new technology can have on the biosensor field. Currently, the research of biosensors is the catalyst for the increased pace of those seeking to make smaller, less expensive, more efficient, and overall faster devices; these sensors may just be the key to the successful integration of biological and electronic systems (Grieshaber et. al. 1439). Healthcare and diagnostics will benefit greatly from any advancements made in the biosensor field (Grieshaber et. al. 1439).
- Grieshaber, Dorothee et al. “Electrochemical Biosensors – Sensor Principles and Architectures.” Sensors (Basel, Switzerland) 8.3 (2008): 1400–1458. Print.
- Pohanka, Miroslav, and Petr Skladal. “Electrochemical biosensors – principles and applications.” Journal of Applied Biomedicine, no. 6, 2008, pp. 57-64. Accessed 30 Apr. 2017.