Glucose biosensor based on glucose oxidase and gold nanoparticles of different sizes covered by polypyrrole layer

Different glucose biosensors based on glucose oxidase (GOx) immobilised on bare carbon rod electrode (CR) modified with gold nanoparticles (Au-NPs) of (i) 3.5 nm (GOx/3.5Au-NPs/CR), (ii) 6 nm (GOx/6Au-NPs/CR) and (iii) 13 nm (GOx/13Au-NPs/CR) were investigated and compared with biosensors based on GOx immobilised on bare CR (GOx/CR). Enzymatic polymerisation of pyrrole was applied to increase linear detection range of biosensors. The influence of the formed polypyrrole layer on sensitivity and Michaelis–Menten kinetics of designed electrochemical biosensors was investigated. The linear glucose detection interval for GOx/CR and GOx/Au-NPs/CR electrodes was dependent on the duration of polymerisation.