An electrochemical biosensor is a technology that converts a chemical signal generated by a reaction with a specific biometric recognition unit into an electrical signal. It has the advantages of high sensitivity, fast response speed, low cost, and small size. It is used in clinical medicine, environmental detection and inspection. Quarantine plays an important role. High catalytic activity metal oxide recognition unit is one of the important development directions of electrochemical biosensor technology. However, the low conductivity of the metal oxide recognition unit severely hinders the electron transfer process in the reaction process, and the sensing performance is poor. Therefore, from the perspective of designing efficient electrochemical biosensor electrode structures, constructing highly conductive nano-film structure conversion units to support high catalytic activity recognition units has become the focus and difficulty of research in this field.
Jiang Xin, a researcher of the Thin Film Materials and Interface Group of the Joint Research Department of the National Research Center for Materials Science, Institute of Metal Research, Chinese Academy of Sciences Nano-walled CuO three-dimensional grid-like electrochemical sensing electrodes are used for glucose molecule detection. The electrochemical sensing electrode exhibits a wide linear detection range (0.5 × 106-4 × 103 M), high sensitivity (1650 μA cm-2 mM-1), low detection limit, and good selectivity and excellent reproduction. And long-term stability, further research found that the electrode showed a good recovery rate (94.21-104.18%) in actual analysis of human serum, and has a high ability to recognize biomolecules.
Fig.1 Three-dimensional mesh diamond / carbon nanowall-loaded CuO nanoparticle electrochemical sensing electrode structure and schematic diagram of biosensor detection
The analysis shows that the excellent electrochemical sensing performance is mainly derived from the diamond / carbon nanowall film electrode with excellent physicochemical properties. On the one hand, carbon nanowalls consist of dozens of layers of graphene sheets grown almost perpendicular to the substrate. Quality open-cell structure, not easy to reunite, stable structure and so on. On the other hand, high Young's modulus diamond penetrates the entire thin film electrode in the form of nano-sheets, which further improves the mechanical structure stability of the electrode in the application process. This unique three-dimensional network structure can accelerate the mass transfer of glucose molecules and timely transfer the electrons generated by the catalytic reaction back to the electrochemical circuit, thereby exhibiting excellent electrical analysis performance and long-term stability.
Fig. 2 Sensitivity, anti-interference, selectivity, and long-term stability test of CuO electrochemical sensor with 3D mesh diamond / carbon nanowall
In addition, the three-dimensional grid-shaped electrochemical sensing electrode is also suitable for carrying other biometric identification units, and shows great potential in the field of high-performance electrochemical biosensors. The carbon nanostructures will also have research value in the fields of electrochemical energy storage and conversion, electrocatalysis and other fields.