BIOSENSORS FOR BLOOD GLUCOSE AND DIABETES DIAGNOSIS: EVOLUTION, CONSTRUCTION, AND CURRENT STATUS

Diabetes mellitus is a worldwide health problem and complications associated with the disease are a significant cause of death in the world. Monitoring the blood glucose level is the first step during diagnosis of diabetes mellitus; hence, rapid and accurate methods of diagnosis is necessary for prevention of lethal complications. Current research is directed toward miniaturization of analytical equipment and also toward a decrease in consumption of biological materials and chemical substances. As a result, biosensors are available for sensitive, accurate, and low cost measurements. The first glucose enzymatic biosensor was proposed by Clark and Lyons (1962). Many different applications and innovations of biosensor have been performed since this work. Biosensors consist of a biorecognition element and physicochemical transducer providing a measurable signal. In case of glucose biosensors, enzyme glucose oxidase is used as a biorecognition element (or biotransducer in some sources) converting glucose to gluconic acid. An electrochemical device was the most common physicochemical transducer for many years, but the optical transducers are becoming more common now. In spite of the advantages of enzymatic glucose biosensors, many disadvantages also were encountered. Consequently, some researchers developed nonenzymatic glucose biosensors. This review covers evolution of glucose biosensors, construction of traditional and marketed types of biosensors, and promising applications.