Nov 30, 2011
Graphene oxide-multiwalled carbon nanotube composite provides electrochemical platform for biosensing
Carbon nanotubes (CNTs) are a promising candidate for the construction of electrochemical biosensors with improved performance. Since pristine CNTs are chemically inert, surface activation is an essential prerequisite. Moreover, the successful immobilization of enzyme onto the modified CNTs is an important step for the assembly of electrochemical biosensors. Based on a multi-step assembly method, researchers at Liaoning University and Tsinghua University, both in China, have come up with a graphene oxide functionalized nanocomposite-based biosensor that paves the way for the immobilization and biosensing of redox enzyme.
The graphene oxide-multiwall carbon nanotubes (GO-MWNTs) were synthesized via a simple self-assembly strategy. As shown in the figure, the pristine MWNTs are assembled onto a graphene oxide nanosheet to form an integrated nanocomposite via the π–π interaction.
The adsorption of the GO nanosheet onto pristine MWNTs not only stabilized the hydrophobic nanotubes, allowing them to disperse well in aqueous solution, but also endowed the MWNTs with a negative charge – further immobilizing the positive charge of redox horseradish peroxidase (HRP) via electrostatic assembly under mild conditions.
Because of the large surface area and conductivity of the nanocomposite, the direct electron transfer between the immobilized HRP and glassy carbon (GC) electrode can be successfully achieved at the HRP/GO-MWNTs/GC electrode. What's more, the biosensor also exhibits an excellent analytical performance towards the reduction of hydrogen peroxide.
The team's results provide a new, simple and efficient method for the fabrication of electrochemical biosensors. In addition, the applications of such a novel nanocomposite in the field of biomedical devices and bioelectronics can also be envisioned.
More information can be found in the journal Nanotechnology.
About the author
This work is a collaboration between the groups of Prof. Xi-Ming Song (Liaoning University, Shenyang, China) and Prof. Jinghong Li (Tsinghua University, Beijing, China). Prof. Li's current research interests include electroanalytical chemistry, bioelectrochemistry and sensors, physical electrochemistry and interfacial electrochemistry, material electrochemistry and graphene. Dr Qian Zhang is an associate professor in the College of Chemistry at Liaoning University, whose research activity covers a wide range of nanostructured materials and their applications. This work is sponsored by the National Basic Research Program of China.