Direct electron transfer: Electrochemical glucose biosensor based on hollow Pt nanosphere functionalized multiwall carbon nanotubes

Herein, a novel third-generation glucose biosensor based on unique hollow nanostructured Pt decorated multiwall carbon nanotubes (HPt-CNTs) composites was successfully constructed. The HPt-CNTs composites were successfully prepared and cast on the glassy carbon electrode (GCE) surface directly. With the help of electrostatic adsorption and covalent attachment, the negative l-cysteine (l-cys) and the positive poly(diallydimethylammonium) chloride (PDDA) protected gold nanoparticles (PDDA-Au) were modified on the resulting electrode surface subsequently, which provided further immobilization of glucose oxidase (GOD). Exploitation of the unique properties of HPt-CNTs composites led to the achievement of direct electron transfer between the electrode and the redox active centers of GOD, and the electrode exhibited a pair of well-defined reversible redox peaks with a fast heterogeneous electron transfer rate. In particular, the detection limit (4 × 10−7 M) of this biosensor was significantly lower and the linear range (1.2 μM–8.4 mM) was much wider than similar carbon nanotubes (CNTs) and Pt-based glucose biosensors. The resulted biosensor also showed high sensitivity and freedom of interference from other co-existing electroactive species, indicating that our facile procedure of immobilizing GOD exhibited better response and had potential application for glucose analysis.

Graphical abstractHollow nanostructured Pt decorated multiwall carbon nanotubes (HPt-CNTs) composites, which led to the achievement of direct electron transfer between the electrode and the redox active centers of GOD, cast on the glassy carbon electrode (GCE) directly, Then negative charged L-cys was bounded to the resulting electrode, facilitating the adsorption of positively charged PDDA-Au to the electrode via electrostatic adsorption and chemisorption. Finally, GOD was self-assembled on the electrode surface firmly. Amperometric experiments and cyclic voltammetric experiments were performed on a workstation by adopt a conventional three electrode system.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Highlights of our research can be summed up in three points. Firstly, hollow nanostructured Pt decorated multiwall carbon nanotubes give prominence to the controlled highly sensitive surface area and low electrical resistance pathway of the biosensor. Secondly, the amplified property of positively charged gold nanoparticles with predefined size and large specific surface areas served as an excellent support for the adsorption of GOD. Lastly, a pair of well-defined reversible redox peaks of GOD exhibited in this biosensor.