Self-assembled perylene-tetracarboxylic acid/multi-walled carbon nanotube adducts based modification of screen-printed interface for efficient enzyme immobilization towards glucose biosensing

Abstract

Enzyme mediated electrodes have been potentially employed to miniature implantable biosensors. The foremost challenge associated with miniaturization is the reduced electrode active surface area for enzyme immobilization, leading to poor output signals. This study aims to maximize glucose oxidase (GOx) loading onto the integrated interface, thereby amplifying the sensing signals. Here we report a sensitive, path-selective, enzyme-mediated glucose biosensor based on self-assembly of perylene-tetracarboxylic acid (PTCA) onto multi-walled carbon nanotubes (MWCNT). Controlled immobilization of GOx onto PTCA decorated MWCNT was accomplished through carbodiimide chemistry to build unprecedented bio-nanohybrid featured with enhanced direct electron transfer (DET) of GOx. This disposable transducing interface was exploited to electrochemical quantification of glucose giving higher glucose sensitivity (0.58 µAmMcm−2) and superior detection limit (35 µM) in the linear range of 1–19 mM. This strategy achieved a larger electrochemical active surface area, providing ample active sites for enhanced enzyme coverage density to eventually result in a superior electrocatalytic activity. The fabricated biosensor paves the way to clinically track fluid-borne glucose with selectivity by impeding the generation of overlapping signals. It was eventually tested for real sample analysis using human blood serum spiked with glucose. It is anticipated that such a design will provide a reliable method for the development of bio-implantable miniaturized sensing interfaces for sensitive and selective detection of glucose even in oxygen saturated media.