Interfacial Langmuir-Blodgett Layer of Functionalized Single-Walled Carbon Nanotubes for Efficient Glucose Sensing

The interfacial layer of single-walled carbon nanotubes (CNTs) introduced between the surface of the electrode and bio-ligands can enhance sensing performance by establishing amplified physical and chemical interaction between them. In this article, we report that an efficient glucose-sensing nanostratified layer can be created on the surface of the working electrode (gold surface) of an electrochemical platform by immobilizing glucose oxidase (GOx) on the highly organized Langmuir–Blodgett (LB) film of octadecylamine functionalized single-walled CNTs (ODACNTs). The amine group of ODACNTs provides stability to the Langmuir monolayer (LM) at the air-water (a/w) interface which is essential for the fabrication of highly ordered LB film. The sensing of glucose was performed in an aqueous medium using GOx immobilized layer onto the LB film and drop-casted film of ODACNTs modified working electrodes. The sensor fabricated using LB film modified electrodes offers a very wide concentration range (10 pM–1 mM), a very low limit of detection (LOD) (10 pM), and a sensitivity $2.8\times $ better than that of drop-casted modified electrodes. The enhanced performance of LB film modified electrode is due to some coherent performance of organized nanotubes in the LB film as compared to a random network of the nanotubes in drop-casted film. The electrodes were characterized at different stages of sensing using grazing incidence X-ray diffraction, field emission scanning electron microscope (FESEM), Raman, and attenuated total internal reflection (ATR)-FTIR spectroscopies.