An amperometric glucose biosensor based on layer-by-layer GOx-SWCNT conjugate/redox polymer multilayer on a screen-printed carbon electrode

Abstract

An amperometric glucose biosensor based on a multilayer made by layer-by-layer assembly of single-walled carbon nanotubes modified with glucose oxidase (GOx-SWCNT conjugates) and redox polymer (PVI-Os) on a screen-printed carbon electrode (SPCE) surface was developed. The SPCE surface was functionalized with a cationic polymer by electrodeposition of the PVI-Os, followed by alternating immersions in anionic GOx-SWCNT conjugate solutions and cationic PVI-O solutions. The purpose is to build a multilayer structure which is further stabilized through the electrodeposition of PVI-Os on the multilayer film. The electrochemistry of the layer-by-layer assembly of the GOx-SWCNT conjugate/PVI-Os bilayer was followed by cyclic voltammetry. The resultant glucose biosensor provided stable and reproducible electrocatalytic responses to glucose, and the electrocatalytic current for glucose oxidation was enhanced with an increase in the number of bilayers. The glucose biosensor displayed a wide linear range from 0.5 to 8.0 mM, a high sensitivity of 32 μA mM −1 cm −2, and a response time of less than 5 s. The glucose biosensor proved to be promising amperometric detectors for the flow injection analysis of glucose.