A growing problem in the population is the increasing number of individuals suffering from forms of liver disease. In liver disease such as hepatitis and cirrhosis, early detection will dramatically increase the odds of survival or severity of disease management. Detection and diagnosis of liver disease would benefit greatly from the development of a rapid and easy detection method. Such a method would be especially vital in economically disadvantaged areas of the world where millions are suffering. In countries such as Egypt, Rwanda and Tanzania levels of hepatitis C infection are estimated to be present in more than 10% of the population with no effective means to monitor due to costs of diagnosis and limited access to medical facilities.
In this research, the ability to detect the presence of liver disease using a quick, low-cost, thick-film, screen-printed biosensor is presented. The sensors utilize a platform sensor technology based on a three-electrode system with the working and counter electrode composed of 5% iridium deposited on Vulcan CX-72R carbon and a Ag/AgCl ink as the reference electrode. Using this sensor technology, two sensors were constructed for the detection of the key biomarkers adenosine deaminase and total bile acid.
The sensor design is based on the immobilization of the enzymes 3α-hydroxysteriod dehydrogenase, for total bile acid, and xanthine oxidase and purine nucleoside phosphorylase, for adenosine deaminase. The enzymatically formed electro-active species H2O2 and NADH are measured using constant potential methods at a potential of +0.27V, versus the Ag/AgCl reference electrode.
Construction of the sensors is described, and their testing in a variety of conditions including: temperature, enzyme level, substrate levels and combinations, and physiological testing fluids are reported. The testing results show that the sensors are suitable for detection of their corresponding biomarkers over the entire testing range with good linear behavior.
In addition to the above research, the versatility of the sensor is shown through its ability to detect the key biomarkers glucose, pyruvate, lactate and phenol. Integration of the sensor with ferricyanide containing liposomes also shows the possible utility of the sensor for detecting viral RNA using a low-cost quick approach.