Development and Characterization of a Visual Eco-Friendly, Cost Effective Glucose Biosensor Using Immobilized Glucose Oxidase on Natural Fibers

Enzymes must be immobilized into a matrix in order to construct a biosensor. The matrix that immobilizes enzyme permits exchange of substrate-containing media. For immobilization of enzymes number of matrices are available. Glucose oxidase, used in the food industry to measure glucose in processed foods, is used in our effort to fabricate and characterize a glucose biosensor. Synthetic materials are generally used to immobilize enzyme but are not biodegradable and produces large amount of waste. We have utilized natural materials as matrices for immobilization of enzyme, including pomelo shell, coconut fiber, onion inner membrane, eggshell inner- membrane, sugarcane fiber, and Luffa cylindrica. Nafion is utilized to attach the enzyme by cross linking to the matrix. Immobilized enzymes activity is monitored by employing substrates such as starch, glucose, honey, and sugarcane juice. The sugarcane juice atpH7.5-8.5, elicits the maximum activity, whereas glucose atpH6- 8, elicits the lowest activity. Matrices exhibit their maximum stability at higher pH values and lower substrate concentrations. With glucose substrate, the stability of the matrices was consistent for six hours. Additionally, we have tried to develop a color-changing optical glucose biosensor using the immobilized GOx enzyme, transforms from blue to colourless with glucose.